Inside Chernobyl (2012)

Inside Chernobyl (2012)



公開日: 2012/04/26
           

EXPAND THIS BOX FOR MORE INFORMATION!

A short film based on current conditions in Chernobyl & Pripyat. Please note, I am an amateur documentary filmmaker and this documentary was made on no budget. The only cost involved were just the travel expenses to the Ukraine.

Follow my next projects on Facebook - http://www.facebook.com/adrianmustofilm

New Directors Cut - https://vimeo.com/77972051

Some frequently asked questions:

Where can I get the music? Purchase it here now! - http://arkitekture.bandcamp.com/album...

What is that bashing sound around the 15 minute mark? The foundations for the new shelter are being bashed into the ground as the soil is too dangerous and radioactive to dig up. The new shelter will cover the crumbling one that currently covers reactor 4. The new shelter will be completed in 2015.

Was I exposed to lots of radiation? In short, no. My dosage of radiation would of been about the same as I would have received on a long haul flight. You also get checked for contamination on the way out of the zone.

Did I have to wear any protective clothing? No, but you are not allowed to wear shorts or short sleeve shirts. You must wear long trousers and jumpers, boots or other hard wearing shoes. Open shoes like sandals are not allowed.

How did I get access to Chernobyl? You can arrange a visit through a company called Solo-East. Google them! A private tour like I took costs $500 a day. I recommend 2-3 days if you can afford it. You will see hardly nothing in just one day. Unfortunately, you are no longer allowed inside buildings.

What camera did I use? It was a Canon 7D with a Canon 17-40mm L & Sigma 10-22mm. Sound was captured with a Sennheiser wireless radio mic and recorded on a Roland R05.

What did you edit this video with? Adobe Premiere CS5 and After Effects CS5.

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Chernobyl power plant in pictures: 25 years since the world's worst nuclear accident

http://www.telegraph.co.uk/news/picturegalleries/worldnews/8461299/Chernobyl-power-plant-in-pictures-25-years-since-the-worlds-worst-nuclear-accident.html

 

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26 April 1986: A photo of the destroyed fourth reactor of the Chernobyl nuclear power plant taken by the plant's official photographer Anatoliy Rasskazov in the first hours after the deadly explosion. A highly radioactive vapour trail is seen coming from the heart of the destroyed reactor. Rasskazov got some 300 Roentgen (fatal is 500 Roentgen) while taking photos of the plant. He died of cancer in 2010.
Picture: AP

© Copyright of Telegraph Media Group Limited 2014

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Chernobyl (2014)

Photographs of Chernobyl and the ghost town of Pripyat by Michael Day

Thursday 13 March 2014

http://www.telegraph.co.uk/news/picturegalleries/worldnews/9128776/Photographs-of-Chernobyl-and-the-ghost-town-of-Pripyat-by-Michael-Day.html

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Haunting images of a once-busy city now abandoned and preserved in time look like a scene from a post-apocalyptic horror film. Pripyat city in the Ukraine once housed the families of thousands of men and women working at the nearby Chernobyl Nuclear Power Plant. But on 26 April 1986 disaster struck when an explosion at the plant caused radiation to leak from its nuclear rector.
An abandoned room inside the Soviet-era Palace of Culture
Picture: Michael Day / Barcroft USA

© Copyright of Telegraph Media Group Limited 2014

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Chernobyl remembered around the world

http://www.telegraph.co.uk/news/picturegalleries/worldnews/8474756/Chernobyl-remembered-around-the-world.html?image=1
  

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© Copyright of Telegraph Media Group Limited 2014
 

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Chernobyl Children International  

http://www.chernobyl-international.com/

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Chernobyl ：google.com/maps

https://www.google.com/maps/@51.3821282,30.1016509,4134m/data=!3m1!1e3?hl=en

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Seconds From Disaster - Meltdown at Chernobyl - FULL - NuclearAdvisor

)

公開日: 2013/02/14

The Chernobyl disaster (Ukrainian: Чорнобильська катастрофа, Chornobylska Katastrofa -- Chornobyl Catastrophe) was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine (then officially Ukrainian SSR), which was under the direct jurisdiction of the central authorities of the Soviet Union. An explosion and fire released large quantities of radioactive particles into the atmosphere, which spread over much of Western USSR and Europe.

The Chernobyl disaster is widely considered to have been the worst nuclear power plant accident in history, and is one of only two classified as a level 7 event on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster in 2011) The battle to contain the contamination and avert a greater catastrophe ultimately involved over 500,000 workers and cost an estimated 18 billion rubles. The official Soviet casualty count of 31 deaths has been disputed, and long-term effects such as cancers and deformities are still being accounted for.


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The Place You Must Always Remember to Forget - Nuclear Waste

)

公開日: 2012/09/15

Documentary on Underground Storage of Nuclear Waste.
Outlines the pros and cons of this method of storage for the tons of waste
produced by the Nuclear Power Industry. Interesting the most difficult threat to
mitigate is the human one.....*sigh. Great Footage, Creative Commons Universal 1.0
Shows building of repository and internal workings at plant.
Spooky Film! When and if we stop nuclear power we are going to need a lot of repositories like Onkalo, (Hiding Place) Perfect name but imperfect solution.
The guy from the Finish Nuclear Authority reminds me of Dr. Strangelove! (50:40)

 

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Chernobyl Nuclear Power Plant

http://en.wikipedia.org/wiki/Chernobyl_Nuclear_Power_Plant

The Chernobyl Nuclear Power Plant or Chornobyl Nuclear Power Station (Ukrainian: Чорнобильська атомна електростанція, Russian: Чернобыльская АЭС) is a decommissioned nuclear power station near the city of Pripyat, Ukraine, 14.5 km (9.0 mi) northwest of the city of Chernobyl, 16 km (9.9 mi) from the Ukraine–Belarus border, and about 110 km (68 mi) north of Kiev. Reactor No. 4 was the site of the Chernobyl disaster in 1986 and the power plant is now within a large restricted area known as the Chernobyl Exclusion Zone.

The nuclear power plant site is to be cleaned by 2065. On January 3, 2010, a Ukrainian law stipulating a programme toward this objective came into effect.^[1]
Construction

The V.I. Lenin Nuclear Power Station (Russian: Чернобыльская АЭС им. В.И.Ленина) as it was known during the Soviet times, consisted of four reactors of type RBMK-1000, each capable of producing 1,000 megawatts (MW) of electric power (3.2 GW of thermal power), and the four together produced about 10% of Ukraine's electricity at the time of the accident.^[2]

The Chernobyl station is 18 km (11 mi) northwest of the city of Chernobyl, 16 km (9.9 mi) from the border of Ukraine and Belarus and about 100 km (62 mi) north of Kiev. Construction of the plant and the nearby city of Pripyat, Ukraine to house workers and their families began in 1970, with Reactor No. 1 commissioned in 1977. It was the third nuclear power station in the Soviet Union of the RBMK-type (after Leningrad and Kursk), and the first ever nuclear power plant on Ukrainian soil.
The completion of the first reactor in 1977 was followed by Reactor No. 2 (1978), No. 3 (1981), and No. 4 (1983). Two more reactors, Nos. 5 and 6, capable of producing 1,000 MW each, were under construction at the time of the accident. Reactor No. 5 was about 70% complete at the time of the accident and was scheduled to start operating in November 7, 1986. However, the works were halted on January 1, 1988 leaving most of the machinery behind.

Reactor Nos. 3 and 4 were second generation units, whereas Nos. 1 and 2 were first-generation units (like those in operation at Kursk Nuclear Power Plant). Second-generation RBMK designs were fitted with a more secure accident localization system, as can be seen in pictures. It is fortunate that the accident happened in a second-generation unit; if it had happened in a first-generation unit, it could have been even more devastating. Today, many countries that were in the Soviet Union have been paid money from the European Union to shut down such first-generation units, as they pose a threat to the environment.^{[citation needed]}

Electrical systems
The power plant is connected to the 330 kV and 750 kV electrical grid. The block has two electrical generators connected to the 750 kV grid by a single generator transformer. The generators are connected to their common transformer by two switches in series. Between them, the unit transformers are connected to supply power to the power plant's own systems; each generator can therefore be connected to the unit transformer to power the plant, or to the unit transformer and the generator transformer to also feed power to the grid.^[3]

The 330 kV line is normally not used, and serves as an external power supply, connected by a station transformer to the power plant's electrical systems. The plant can be powered by its own generators, or get power from the 750 kV grid through the generator transformer, or from the 330 kV grid via the station transformer, or from the other power plant block via two reserve busbars. In case of total external power loss, the essential systems can be powered by diesel generators. Each unit transformer is connected to two 6 kV main power boards, A and B (e.g. 7A, 7B, 8A, 8B for generators 7 and 8), powering principal non-essential drivers and connected to transformers for the 4 kV main power and the 4 kV reserve busbar.^[3]

The 7A, 7B, and 8B boards are also connected to the three essential power lines (namely for the coolant pumps), each also having its own diesel generator. In case of a coolant circuit failure with simultaneous loss of external power, the essential power can be supplied by the spinning down turbogenerators for about 45–50 seconds, during which time the diesel generators should start up. The generators are started automatically within 15 seconds at loss of off-site power.^[3]

Turbo generators
The electrical energy is generated by a pair of 500 MW hydrogen-cooled turbo generators. These are located in the 600 m (1,969 ft)-long machine hall, adjacent to the reactor building. The turbines—the venerable five-cylinder K-500-65/3000—are supplied by the Kharkiv turbine plant; the electrical generators are the TBB-500. The turbine and the generator rotors are mounted on the same shaft; the combined weight of the rotors is almost 200 t (220 short tons) and their nominal rotational speed is 3000 rpm.^[4]

The turbo generator is 39 m (128 ft) long and its total weight is 1,200 t (1,300 short tons). The coolant flow for each turbine is 82,880 t/h. The generator produces 20 kV 50 Hz AC power. The generator's stator is cooled by water while its rotor is cooled by hydrogen. The hydrogen for the generators is manufactured on-site by electrolysis.^[4] The design and reliability of the turbines earned them the State Prize of Ukraine for 1979.

The Kharkiv turbine plant (now Turboatom) later developed a new version of the turbine, K-500-65/3000-2, in an attempt to reduce use of valuable metal. The Chernobyl plant was equipped with both types of turbines; Block 4 had the newer ones. The newer turbines, however, turned out to be more sensitive to their operating parameters, and their bearings had frequent problems with vibrations.^[5]

Reactor Fleet
Four RMBK reactors were at Chernobyl, NPP. Chernobyl-3 performed a total power loss test like the kind that caused the accident at #4. Reactors #1-3 continued to operate until their shutdown in the 1990s. #5-#6 were cancelled, and partially completed.

Accidents

1982
In 1982, a partial core meltdown occurred in Reactor No. 1 at the Chernobyl plant. The extent of the accident was not made public until years later, in 1985. The reactor was repaired and put back into operation within months.

1986
Main articles: Chernobyl disaster and Chernobyl disaster effects

On Saturday, April 26, 1986, a disaster occurred at Reactor No. 4, which has been widely regarded as the worst accident in the history of nuclear power. As a result, Reactor No. 4 was completely destroyed and is being enclosed in a concrete and lead sarcophagus to prevent further escape of radioactivity. Large areas of Europe were affected by the accident. The radioactive cloud spread as far away as Norway.

1991 fire
The Chernobyl Nuclear Plant utilized one large, open turbine hall for all four reactors without any separating walls.^{[citation needed]} Each reactor had two turbines. On October 11, 1991, a fire broke out in the turbine hall of Reactor No. 2.^[6] The fire began in Reactor No. 2's Turbine 4^{[citation needed]} (ТГ-4 in Russian) while the turbine was being idled for repairs. A faulty switch caused a surge of current to the turbine, igniting insulating material on some electrical wiring.^[7] This subsequently led to hydrogen, used as a turbine coolant, being leaked into the turbine hall "which apparently created the conditions for fire to start in the roof and for one of the trusses supporting the roof to collapse." ^[8] The adjacent reactor hall and reactor were unaffected.

Ukraine's 1991 independence from the Soviet Union generated further discussion on the Chernobyl topic, because the Rada, Ukraine's new parliament, was composed largely of young reformers. Discussions about the future of nuclear energy in Ukraine helped move the government toward the political decision to cancel the operation of Reactor No. 2.^{[citation needed]} 2013 collapse
On February 12, 2013, a 604 square metre (6,500 square foot) portion of the roof and wall adjacent to the covered part of the turbine hall collapsed into the entombed area of the turbine hall. The collapse did not affect any other part of the Object Shelter or the New Safe Confinement. No variances in radiation levels as a result of the incident were detected.^[9] The roof which collapsed was built after the Chernobyl disaster.^[10]

Decommissioning
After the explosion at Reactor No. 4, the remaining three reactors at the power plant continued to operate. In 1991, Reactor No. 2 suffered a major fire, and was subsequently decommissioned.^[11] In November 1996, Reactor No. 1 was shut down, followed by Reactor No. 3 on December 15, 2000, making good on a promise by Ukrainian president Leonid Kuchma that the entire plant would be closed.^[11]

Even after the last reactor shutdown, people continue to work at the Chernobyl plant until Reactor Nos. 1, 2, and 3 are totally decommissioned, which is expected to take years. The first stage of decommissioning is the removal of the highly radioactive spent nuclear fuel, which is placed in deep water cooling ponds. However, storage facilities for this are not suitable for long term containment, and those on site do not have the capacity for all the spent fuel from Nos. 1, 2 and 3. A second facility is planned for construction that will use dry storage technology suitable for long term storage and have the required capacity.^[12]

Removal of uncontaminated equipment has begun at Reactor No. 1 and this work could be complete by 2020–2022.^[13]

Main article: Chernobyl disaster#Radioactive waste management

The remains of Reactor No. 4 will remain radioactive for some time. The isotope responsible for the majority of the external gamma radiation dose at the site is caesium-137, which has a half-life of about 30 years. It is likely that with no further decontamination work the gamma ray dosage at the site will return to background levels in about 300 years. However, most of the alpha emitters are longer lived, and the soil and many surfaces in and around the plant are likely to be contaminated with transuranic metals such as plutonium and americium, which have much longer half-lives. It is planned that the reactor buildings will be disassembled as soon as it is radiologically safe to do so.

Sarcophagus replacement
Main article: New Safe Confinement

Originally announced in June 2003, a new steel containment structure named the New Safe Confinement (NSC) would be built to replace the aging and hastily-built sarcophagus that currently protects Reactor No. 4. Though the project's development has been delayed several times, construction officially began in September 2010. The New Safe Confinement is financed by an international fund managed by the European Bank for Reconstruction and Development (EBRD), is being designed and built by the French-led consortium Novarka, which includes the companies Bouygues and Vinci. Novarka is building a giant arch-shaped structure out of steel, 190 m (623 ft) wide and 200 m (656 ft) long to cover the old crumbling concrete dome that is currently in use.

This steel casing project is expected to cost $1.4 billion (£700 million, €1 billion), and expected to be completed in 2015.^[14] A separate deal has been made with the American firm Holtec to build a storage facility within the exclusion zone for nuclear waste produced by Chernobyl.^[15][16][17]

The shelter replacement will require demolition of the tall red and white exhaust chimney which was used for both Reactors No. 3 and 4. A shorter stack has been constructed adjacent to it that will be used to ventilate the new shelter.^{[citation needed]} Demolition of the original chimney started in November of 2013.

Tours to Chernobyl
The Chernobyl zone administration allows tourists to visit Chernobyl exclusion zone as well as the teritorry of Chernobyl nuclear power plant. There are many agencies selling these tours, however for save booking and maximum program with official permissions it is advised to contact Chernobyl tour operators. You can find some of them at Wikivoyage ^[18] or at Chernobyl Tour Operator Association website ^[19]

See also 
Chernobyl articles:
Chernobyl compared to other radioactivity releases
Chernobyl disaster
Chernobyl disaster effects
Chernobyl Heart
Cultural impact of the Chernobyl disaster
List of Chernobyl-related articles
List of Chernobyl-related charities
Zone of alienation

Other accidents:
List of civilian nuclear accidents
List of military nuclear accidents
Three Mile Island accident

Nuclear safety:
International Nuclear Event Scale
Loss-of-coolant accident
Nuclear meltdown
Radioactive contamination

General:
List of nuclear reactors
Nuclear power
Radiotrophic fungus

External links
Chernobyl Nuclear Power Plant – official website (Ukrainian) English icon on home page
Chernobyl Nuclear Power Plant at Google Maps
Steel Sarcophagus Announcement.
«Zone – virtual walk with comments» (Russian) by Nataliya Monastirnaya

This page was last modified on 11 March 2014

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Comparison of Chernobyl and other radioactivity releases

http://en.wikipedia.org/wiki/Comparison_of_Chernobyl_and_other_radioactivity_releases

This article compares the radioactivity release and decay from the Chernobyl disaster with various other events which involved a release of uncontrolled radioactivity.

Chernobyl compared to background radiation
Natural sources of radiation are very prevalent in the environment, and come from cosmic rays, food sources (bananas have a particular high source), radon gas, granite and other dense rocks, and others. The collective radiation background dose for natural sources in Europe is about 500,000 man Sieverts per year. The total dose from Chernobyl is estimated at 80,000 man sieverts, or roughly 1/6 as much.^[1] However, some individuals, particular in areas adjacent the reactor, received significantly higher doses.

Chernobyl's radiation was detectable across Western Europe. Average doses received ranged from 0.02 mrem (Portugal) to 38 mrem (portions of Germany).^[1]

Chernobyl compared with an atomic bomb
Far fewer people died as an immediate result of the Chernobyl event than the immediate deaths from radiation at Hiroshima. Chernobyl is eventually predicted to result in up to 4,000 total deaths from cancers, sometime in the future, according to the WHO and create ~ 41,000 excess cancers according to the International Journal of Cancer, with, depending on treatment, not all cancers resulting in death.^[2][3] Due to the differences in half-life the different radioactive fission products undergo exponential decay at different rates. Hence the isotopic signature of an event where more than one radioisotope is involved will change with time.

Some comments have been made in which the radioactive release of the Chernobyl event is claimed to be 300^[4] or 400^[5] times that of the bomb dropped on Hiroshima. The work of SCOPE^[6][7] suggests that the two events can not be simply compared with a number suggesting that one was XX times larger than the other.

The radioactivity released at Chernobyl tended to be more long lived than that released by a bomb detonation hence it is not possible to draw a simple comparison between the two events. Also, a dose of radiation spread over many years (as is the case with Chernobyl) is much less harmful than the same dose received over a short period. The relative size of the Chernobyl release when compared with the release due to a hypothetical ground burst of a bomb similar to the Fat Man device dropped on Nagasaki.

Isotope	Ratio between the release due to the bomb and the Chernobyl accident
90Sr	1:87
137Cs	1:890
131I	1:25
133Xe	1:31

A comparison of the gamma dose rates due to the Chernobyl accident and the hypothetical nuclear weapon.

The graph of dose rate as a function of time for the bomb fallout was done using a method similar to that of T. Imanaka, S. Fukutani, M. Yamamoto, A. Sakaguchi and M. Hoshi, J. Radiation Research, 2006, 47, Suppl A121-A127. Our graph exhibits the same shape as that obtained in the paper. The bomb fallout graph is for a ground burst of an implosion-based plutonium bomb which has a depleted uranium tamper. The fission was assumed to have been caused by 1 MeV neutrons and 20% occurred in the ²³⁸U tamper of the bomb. It was assumed, for the sake of simplicity, that no plume separation of the isotopes occurred between the detonation and the deposit of radioactivity. The following gamma-emitting isotopes are modeled ¹³¹I, ¹³³I, ¹³²Te, ¹³³I, ¹³⁵I, ¹⁴⁰Ba, ⁹⁵Zr, ⁹⁷Zr, ⁹⁹Mo, ^99mTc, ¹⁰³Ru, ¹⁰⁵Ru, ¹⁰⁶Ru, ¹⁴²La, ¹⁴³Ce, ¹³⁷Cs, ⁹¹Y, ⁹¹Sr, ⁹²Sr, ¹²⁸Sb and ¹²⁹Sb. The graph ignores the effects of beta emission and shielding. The data for the isotopes was obtained from the Korean table of the isotopes.
The graphs for the Chernobyl accident were computed by an analogous method.

A ground burst of a nuclear weapon creates considerably more local deposited fallout than the air bursts used at Hiroshima or Nagasaki. This is due in part to Neutron activation of ground soil and greater amounts of soil being sucked into the nuclear fireball in a ground burst than in a high air burst. In the above neutron activation is neglected, and only the fission product fraction of the total activity resulting from the ground burst is shown.


Chernobyl compared with Tomsk-7
The release of radioactivity which occurred at Tomsk-7 (an industrial nuclear complex located in Seversk rather than the city of Tomsk) in 1993 is another comparison with the Chernobyl release. During reprocessing activities, some of the feed for the second cycle (medium active part) of the PUREX process escaped in an accident involving red oil. According to the IAEA it was estimated that the following isotopes were released from the reaction vessel:^[8]

● ¹⁰⁶Ru 7.9 TBq
● ¹⁰³Ru 340 GBq
●　⁹⁵Nb 11.2 TBq
●　⁹⁵Zr 5.1 TBq
●　¹³⁷Cs 505 GBq (estimated from the IAEA data)
●　¹⁴¹Ce 370 GBq
●　¹⁴⁴Ce 240 GBq
●　¹²⁵Sb 100 GBq
●　²³⁹Pu 5.2 GBq

It is important to note that the very short lived isotopes such as ¹⁴⁰Ba and ¹³¹I were absent from this mixture, and the long lived ¹³⁷Cs was only at a small concentration. This is because it is not able to enter the tributyl phosphate/hydrocarbon organic phase used in the first liquid-liquid extraction cycle of the PUREX process. The second cycle is normally to clean up the uranium and plutonium product. In the PUREX process some zirconium, technetium and other elements are extracted by the tributyl phosphate. Due to the radiation induced degradation of tributyl phosphate the first cycle organic phase is always contaminated with ruthenium (later extracted by dibutyl hydrogen phosphate).

Because the very short lived radioisotopes and the relatively long lived caesium isotopes are either absent or in low concentrations the shape of the dose rate vs. time graph is different from Chernobyl both for short times and long times after the accident.

The size of the radioactive release at Tomsk-7 was much smaller, and while it caused moderate environmental contamination it did not cause any early deaths.

Chernobyl compared with the Goiânia accident
While both events released ¹³⁷Cs, the isotopic signature for the Goiânia accident was much simpler.^[9] It was a single isotope which has a half-life of about 30 years. To show how the activity vs. time graph for a single isotope differs from the dose rate due to Chernobyl (in the open air) the following chart is shown with calculated data for a hypothetical release of ¹⁰⁶Ru.

Chernobyl compared with the Three Mile Island accident

Main article: Three Mile Island accident
Three Mile Island-2 was an accident of a completely different type from Chernobyl. Chernobyl was a design flaw-caused power excursion causing a steam explosion resulting in a graphite fire, uncontained, which lofted radioactive smoke high into the atmosphere; TMI was a slow, undetected leak that lowered the water level around the nuclear fuel, resulting in over a third of it shattering when refilled rapidly with coolant. Unlike Chernobyl, TMI-2's reactor vessel did not fail and contained almost all of the radioactive material. Containment at TMI did not fail. A small quantity of radioactive gases from the leak were vented into the atmosphere through specially designed filters under operator control. A government report concluded that the accident caused no increase in cancer rates for local residents.^[10]

Chernobyl compared with criticality accidents
During the time between the start of the Manhattan project and the present day, a series of accidents have occurred in which nuclear criticality has played a central role. The criticality accidents may be divided into two classes. For more details see nuclear and radiation accidents. A good review of the topic was published in 2000, "A Review of Criticality Accidents" by Los Alamos National Laboratory (Report LA-13638), May 2000. Coverage includes United States, Russia, United Kingdom, and Japan. Also available at this page, which also tries to track down documents referenced in the report.

● Press release on a report on criticality accidents from Los Alamos National Laboratory
● List of radiation accidents
● U.S. report from 1971 on criticality accidents to date

Process accidents
In the first class (process accidents) during the processing of fissile material, accidents have occurred when a critical mass has been created by accident. For instance at Charlestown, Rhode Island, United States on July 24, 1964 one death occurred and at Tokaimura, Japan, nuclear fuel reprocessing plant, on September 30, 1999^[11] two deaths and one non fatal overexposure occurred as result of accidents where too much fissile matter was placed in a vessel. These accidents tend to lead to very high doses due to direct irradiation of the workers within the site, but due to the inverse square law the dose suffered by members of the general public tends to be very small. Also very little environmental contamination normally occurs as a result of these accidents. A release of radioactivity occurred as a result of the Tokaimura event. The building in which the accident occurred was not designed as a containment building, yet it was able to retard the spread of radioactivity. Because the temperature rise in the nuclear reaction vessel was small, the majority of the fission products remained in the vessel.

Reactor accidents
In this type of accident a reactor or other critical assembly releases far more fission power than was expected, or it becomes critical at the wrong moment in time. The series of examples of such events include one in an experimental facility in Buenos Aires, Argentina, on September 23, 1983 (one death)^[12] and during the Manhattan Project several people were irradiated (two, Harry K. Daghlian and Louis Slotin, fatally) during "tickling the dragon's tail" experiments. These accidents tend to lead to very high doses due to direct irradiation of the workers within the site, but due to the inverse square law the dose suffered by members of the general public tends to be very small. Also very little environmental contamination normally occurs as a result of these accidents. For instance at Sarov according to the IAEA report (2001)^[13] the radioactivity remained confined to within the actinide metal objects which were part of the experimental system. Even the SL-1 accident failed to release much radioactivity outside the building in which it occurred.

See also
●  Chernobyl
●  Chernobyl Children's Project International
●  Chernobyl disaster effects
●  Chernobyl Heart
●  Chernobyl Shelter Fund
●  Liquidator (Chernobyl)
●  List of Chernobyl-related articles
●  Nuclear power debate
●  International Nuclear Event Scale
●  Fukushima Daiichi nuclear disaster 

This page was last modified on 19 February 2014 

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チェルノブイリ原発周辺住民の急性放射線障害に関する記録

http://www.rri.kyoto-u.ac.jp/NSRG/Chernobyl/saigai/Lupan-j.html

ウラジーミル・ルパンディン

ロシア科学アカデミー・社会学研究所（ロシア）

1992年の３月と６月にわれわれは，1986年４月26日に事故を起こしたチェルノブイリ原発にほど近いベラルーシ共和国ゴメリ州ホイニキ地区の地区中央病院において，事故当時に作成された医療記録の調査を行なった．
その結果，事故から数週間の間に記録された82件の放射線被曝例を発見したことは以前に報告した¹．そのうち８件は急性放射線症と認められるものであった．

われわれの報告は，ベラルーシ，米国，日本において関心を惹き起こした^2,3．
しかしながら，それら1986年５月から６月にかけての医療記録を詳しく分析することは，事故直後のホイニキ地区における放射線状況や被曝量に関する情報がなかったり（また歪曲されたり）していたため困難であった．事故の規模を検討する上で最も基本的な情報である，事故直後の放射線状況に関するすべてのデータは，当時の慣例に従って，ソ連水理気象委員会によって秘密にされていた．ホイニキ地区のデータは（すべてのデータはミンスクの共和国記録局へ送られていた），ベラルーシの水理気象委員会によって秘密にされた．

1996年にわれわれは，ホイニキ地区の事故直後の放射線状況に関して信頼できる情報を得ることができた．ホイニキ地区の民間防衛隊の班長が個人的なメモとして保管していたデータである．その民間防衛隊のデータを，ホイニキ地区の衛生管理センターに別途保管されていたデータと照らし合わせてみると，よく一致することが判明した．

個人や地方レベルで得られたデータを否定するため，それらの測定は，よく訓練されていない人が信頼性の不確かな測定器を用いたものである，という指摘がしばしば行なわれる．しかし，今回われわれが得たデータにこのことは当てはまらない．

ホイニキ地区民間防衛隊の班長であるアレクサンドル・カユーダは，1983年まで原子力潜水艦に技師として勤務していた．彼の任務は，原子炉の保守に加えて，原子炉区画の放射線を測ることであった．1983年から彼は，ホイニキ地区民間防衛隊の班長をつとめていた．チェルノブイリ事故以前にも彼は，原発から10～20㎞地域の放射線量の測定をDP-5（訳注・ガイガーカウンター式放射線測定器）で行なっていた．1985年６月には，ラージン村の近くで240～250マイクロレントゲン／時という値を測定している（同じ測定器による潜水艦の原子炉区画の測定は40マイクロレントゲン／時程度であった）．ラージン村の放射線量上昇の原因は，チェルノブイリ原発からの放射能洩れ以外に考えられない．

民間防衛隊のデータに基づくと，1986年４月26日と27日の段階ではホイニキ地区において，組織的な放射線測定は，軍隊も含め行なわれていない．民間防衛隊本部による最初の放射線測定が行なわれたのは４月28日午前８時であった．そのときの各居住区の放射線量は以下のようであった．

• ホイニキ市：８ミリレントゲン／時
• ストレリチェボ村：14ミリレントゲン／時
• ドゥロニキ村：30ミリレントゲン／時
• オレビチ村：89ミリレントゲン／時
• ボルシチェフカ村：120ミリレントゲン／時
• ラージン村：160ミリレントゲン／時
• ウラーシ村：300ミリレントゲン／時
• チェムコフ村：330ミリレントゲン／時
• マサニ村：500ミリレントゲン／時

４月28日夕方に開かれた地区の評議会で地区民間防衛隊は，住民の多くが数100レムにも及ぶ全身被曝をうける恐れがあるので，当時の住民に対する放射線防護の指針に照らして，地区住民の大部分を速やかに避難させるべきである，と報告した．ゴメリ州民間防衛隊本部長のジューコフスキー（エネルギー工学の技師）と，オブニンスク原発から駆けつけてきていた核物理学者たちが，地区民間防衛隊の意見を支持した．しかし，地区の行政責任者は，地区や州の民間防衛隊の要請を却下したのであった．

５月１日になって，周辺30㎞圏内の子供と妊婦の避難が開始され，５月５日には残りの住民の避難が始まった．結局，地区では5200人の住民が避難した．すべての避難住民は，地区中央病院で検査をうけたが，病院は５月５日から野戦病院として軍組織に組み込まれた．つまり，その日から地区中央病院では，セベロモルスク，セベロドゥビンスク，極東などからやってきた軍医や専門家たちが活動をはじめた．

野戦病院に入院させる基準は以下のとおりであった．

• 甲状腺からのガンマ線量が1000マイクロレントゲン／時以上，
• 上着，靴，皮膚および下着の汚染が100マイクロレントゲン／時以上，
• ガンマ線に基づく体内の汚染（甲状腺，肝臓，腎臓，生殖器）が800～1000m Ci．

これらの基準に従い，約１万2000人のホイニキ地区住民が野戦病院で入院検査をうけた（事故当時の地区の人口は３万2000人）．

ホイニキ地区中央病院の記録保管室から（約１万2000件の）入院カルテが盗まれたのは，1990年の11月のことであった．盗難の後，記録保管室の整理はされず，われわれの調査によって，残されていたカルテが隣接建屋の屋根裏から見つかった．すでに述べたように，それらの中から，1986年５月１日から６月中旬にかけて放射能汚染地域から地区中央病院にやってきた，82件の放射線被曝例が見つかった．この82件という数字は，正体不明の犯人によるカルテ盗難の後に残されていた数であり，全体のごく一部分にすぎないであろう．そのうち22例は，隣のブラーギン地区住民であり，ここでの検討からは除外する．

軍野戦病院
病院から見つかった60例のカルテを検討する．カルテの記述はすべて，きわめて簡単である．このことは，当時の仕事量の膨大さと検閲への配慮をうかがわせる．とりわけ検閲が厳しかったことをうかがわせるのは，退院時に記入されている診断名である．放射線障害に関連する診断をわれわれは１件も見つけることができなかった．

しかしながら，放射能汚染地域から病院へやってきた理由を記した入院指令票の記述は検閲をうかがわせず，われわれの興味を惹くのは，カルテの中に残っていたその指令票の内容である．

入院指令票に記されていた入院理由は，たとえばつぎの通りである．

1. 第２度急性放射線障害
2. 甲状腺からの放射線レベル－10～16ミリレントゲン／時
3. 全身の衰弱，頭痛，腹痛，吐き気，おう吐，下肢のむくみ
4. 汚染地域の幼児
5. 放射線量上昇地域の滞在と血液検査値の変化（白血球数2500）のための検査入院
6. 吐き気，おう吐，唾液分泌の増大，甲状腺からのガンマ線3000マイクロレントゲン／時以上
7. 放射能汚染，甲状腺3000マイクロレントゲン／時以上
8. 白血球減少：白血球数2300，頭痛
9. 放射能汚染との結論で救護所から転送．甲状腺３ミリレントゲン／時以上，白血球数2900
10. 事故時にチェルノブイリ原発から300mの地点に滞在，白血球数2900
11. 放射能汚染，肝臓５～10ミリレントゲン／時，甲状腺1.5ミリレントゲン／時
12. 顔，手首の放射線火傷
13. 放射線障害，鼻血

　野戦病院へ送られてきた理由の記述とともに，患者の自覚症状についての記述も注目される．頭痛，急な衰弱，吐き気をともなう複合症状がもっとも多く，全体の患者の30％以上に達している．これは，自律神経失調症と呼ばれる症状である．つぎに多い複合症状は，おう吐，腹痛，めまい，食欲不振，心臓部の痛み，口内の乾きや苦みといった症状で，10%程度である．さらに，神経・循環系失調（自律神経失調＋心臓部の痛み）といった症状が認められる（13％）．
カルテに記されている患者の訴えを一覧にまとめると，

• 頭痛（30例），急な衰弱（29），おう吐（20），めまい（10），心臓部の痛み（８），吐き気（７），食欲不振（７），口の渇き・苦み（７），唾液分泌増加（３），関節痛（３），喉のがらがら（３），眠気（２），下痢（２），睡眠障害（２），右の肋骨下部（肝臓）の痛み（２）．１例ずつ記録されているのはつぎの症状：高熱，便秘と排尿困難，行動の遅鈍，鼻血，出血，耳鳴，皮膚痒症，発汗，から咳．

患者たちが送られてきた居住区は以下の通りである．ホイニキ市，プリピャチ市，ボルシチェフカ村，オレビチ村，ウラーシ村・ポゴンノエ村，モロチキ村，カジュシキ村，ドゥロニキ村，フボシチェフカ村，チェムコフ村，ベリーキーボル村，ビソーカヤ村，ブドーブニク村，ノボセルキ村，ロマチ村，マレシェフ村，ノボパクロフカ村，クリビ村，アメリコフシチナ村，エラポフ村，プダコフ村，トゥリゴボチ村，ベレチン村，チェヒ村，ドゥボリシチェ村，ルドノエ村．
　カルテの分析の結果，60例をつぎの３グループに分類した．
　１．急性放射線症：８例
　２．放射線被曝症状：20例
　３．明瞭な臨床症状のない甲状腺からの高ガンマ線量例：32例
　以下，急性放射線症と放射線被曝症状の個々の症例について紹介する．

急性放射線症
１．クリチェンコ，ニコライ・アレクセイビッチ（仮名）20歳男性，ボルシチェフカ村より．
病院へ入院時期：５月１日午前２時．入院のときの訴え：何度も繰り返される嘔吐，全身衰弱，胃痛（上腹部，左側），頭痛，口渇．

経過：日光浴と魚釣りをするためボルシチェフカ村の親類宅にやってきた．４月26日27日の両日をプリピャチ河畔で過ごした．４月28日に嘔吐が生じ（１昼夜に６度），吐き気，胃痛，高熱（39度）．便秘が認められた．４月30日医師の指示で解毒剤を服用．
医師の診察結果：無気力．舌の白濁．３日間便秘．体温：36.6度．ガンマ線の測定結果：衣服がひどく汚染．肝臓からのガンマ線量５～10ミリレントゲン／時，甲状腺からのガンマ線量1.5ミリレントゲン／時．

５月１日午前５時30分の診察結果：全身衰弱，吐き気，嘔吐（病院へ入院時から１度），尿閉と便秘．５月１日日中の患者の容体：会話困難．頭痛，めまい，何度も繰り返される嘔吐に対する訴え．

血液検査結果：白血球数3600，血小板数26万．尿検査結果：蛋白量4.56ｇ／㍑．５月３日，ゴメリ州立病院に転院．

患者に関する追加情報：４月29日，民間防衛隊医療班長のＶ・Ｉ・コビルコが患者を村で診察．会話困難，頭痛，衰弱，何度も繰り返される嘔吐に対する訴え．村にきて，４月26日と27日プリピャチ河畔で魚釣りをしたと述べる．５月１日，地区中央病院で再びコビルコの診察をうける．重症の状態が続き，会話困難．診断：第２度または第３度急性放射線症．

　患者がやってきたボルシチェフカ村は，チェルノブイリ原発の北方17.5㎞，プリピャチ川右河畔にある．1986年１月１日の住民数は311人．

　ボルシチェフカ村の放射線量の測定：ホイニキ地区民間防衛隊のデータによると，４月28日のボルシチェフカ村の放射線レベルは120ミリレントゲン／時であった．５月20日，ボルシチェフカ村高度300ｍの大気中の測定は28ミリレントゲン／時，地上では50ミリレントゲン／時．ホイニキ地区衛生管理センターのデータによると，４月29日のボルシチェフカ村のガンマ線量率は60～100ミリレントゲン／時，ストロンチウム90の汚染密度は13.4Ci/km²．

筆者の見解：患者の臨床経過は，第３度急性放射線症に相当している．彼の被曝量はおそらく300レムを越えているだろう．患者が被曝したのは，主に４月26日と27日の２日間であるから，このことは，この２日間，ボルシチェフカ村周辺の放射線レベルが非常に高かったことをもの語っている．４月28日の放射線レベルが120ミリレントゲン／時であったことを考えると，非常に高いレベルの放射線をもたらしたのは，かなり短い半減期の放射能であったと結論できる．

重篤な被曝症状に至ったのは，放射線レベルが高かったことのみならず，患者が日光浴をしたこととも関連している（暑い天気が続いた）．1986年4月26月と27日の両日，プリピャチ川の河畔で休暇を過ごしていたのが患者一人だけでなかったことは容易に想定できる．この両日，野外で上着を脱いで過ごし大きな被曝をうけた人々が，ホイニキ地区から遠く離れた地域に至るまで大勢いたことであろう．

２．カルテ№2505/467．（氏名略）ボルシチェフカ村住民，男性47歳，コルホーズ「５月１日」の搾乳係．５月２日２時45分，地区中央病院入院．ポゴンノエ村診療所長からの転送．入院理由：第２度急性放射線症．入院時に，吐き気，嘔吐，脱力感，胃痛に対する訴え．５月１日，上腹部の痛み，吐き気と嘔吐が生じて発病と述べる．５月２日16時30分の診察：嘔吐は繰り返されず，容体好転．胃の痛み．血液検査：白血球4700．
　５月４日，患者は無断で退院．

３．カルテ№7539/464．（氏名略）男性82歳，ボルシチェフカ村住民．５月３日，地区中央病院入院．全身衰弱，頭痛，胃の痛み，嘔吐に対する訴え．夜までに，下肢のむくみが現れた．５月４日，病院から退去．

４．カルテ№2520/476．（氏名略）女性48歳．５月３日，モロチキ村から入院．４月28日，発病の徴候．吐き気，嘔吐，激しい全身衰弱，１日４回の水っぽい便．４月30日，医師に相談．
５月３日の診察：患者は，上腹部の痛み，吐き気，嘔吐，流涎を訴える．甲状腺からの放射線3000マイクロレントゲン／時（５月７日）．白血球，3500（５月９日）．５月13日退院．
筆者の見解：第１度から第２度の急性放射線症を，臨床経過，放射能汚染地域への滞在，甲状腺からの放射線量ならびに白血球減少症が示している．患者の容体中，腸の障害が注目される．４月28日に急性放射線症の最初の徴候が現れたことは，彼女が４月26日と27日にかけて100レム以上の被曝をうけたことをもの語っている．患者はチェルノブイリ原発から20㎞，住民数124人のモロチキ村に住んでいた．民間防衛隊のデータによれば，４月28日のモロチキ村の放射線量は280ミリレントゲン／時（ボルシチェフカ村の２倍）．衛生管理センターのデータでは，４月29日に130～190ミリレントゲン／時，４月30日は60～70ミリレントゲン／時でストロンチウムの汚染は25Ci/km²．

５．（氏名略）男性35歳，ドゥロニキ村住民，ソフホーズ「オレビッチィ」で働く．５月３日，地区中央病院入院．訴え：脱力感，めまい，吐き気，嘔吐．４月28日発病．脱力感，吐き気，嘔吐が生じた．これらの症状が１週間（４月28日から５月２日まで）消えなかった．５月３日容体が悪化した．５月３日の診察：患者は行動が若干鈍化，60ラドの被曝をうけたと述べる．５月６日退院．
　ドゥロニキ村は原発から35㎞，住民数232人．民間防衛隊のデータによれば，４月28日の放射線量は30ミリレントゲン／時．衛生管理センターのデータによれば，同じ日に26～28ミリレントゲン／時，ストロンチウム90の汚染は2.7Ci/km²．

６．カルテ № 8977/438．（氏名略）男性55歳，アメリコフシチナ村住民．５月10日入院．５月４日発病．全身衰弱，胃の痛み，下痢，吐き気，嘔吐が生じた．患者の訴え：水っぽい便，胃の痛み，脱力感．血液検査：白血球3200．

７．カルテ№ 8302/602．（氏名略）女性57歳，クリビ村（原発から70㎞）住民．放射能汚染地域に滞在していたため６月11日に入院．病状が１ヶ月前から継続．訴え：右肋骨下部の痛み，吐き気，嘔吐，めまい，全身衰弱，胃，背中，頸，足の痛み．５月20日に１回嘔吐．６月10日の血液検査：白血球2500，血小板16.5万，赤血球363万，血圧210/115．

８．カルテ№7588．（氏名略）２歳７ヶ月の幼女，ポゴンノエ村．５月４日入院．入院理由：潰瘍性口内炎，高汚染地域からの子供．訴え：食事拒否，流涎．また，唇，口内，頬の腫れ・炎症．体温37.8度．５月６日，口内炎が消えない，州立こども病院に転院．
　ポゴンノエ村（住民数1503人）は，チェルノブイリ原発から27㎞．衛生管理センターのデータによれば，４月28日，放射線量は30～35ミリレントゲン／時，ストロンチウム汚染は10Ci/km²．
患者の症状に嘔吐は認められなかったが，われわれはこのケースを急性放射線症に加えた．潰瘍性口内炎はベータ線被曝による障害と解釈されるし，食物拒否，高熱，流涎は容体の深刻さを物語っている．
　以上の医療記録から以下のように言える．患者たちは1986年４月26日から汚染地域に滞在し，かなりの放射線被曝をうけた．すべての患者に，急性放射線症を特徴づける臨床状態が共通して認められる．われわれのリストの中で，患者クリチェンコの症例はきわだっており，彼のケースは，チェルノブイリ原発周辺30㎞圏内での急性放射線症の典型例と言えるであろう．

放射線被曝症状
放射線被曝症状はつぎに述べる臨床症状に分類される．
　１．血液像症状：血球減少症，白血球減少症
　２．自律神経失調症
　３．神経・循環系失調症
　４．咽頭部障害
　５．粘液・皮膚のベータ線障害
  ６．甲状腺の高レベル被曝

白血球減少症：
９．カルテ7784.（氏名略）女性65歳，アメリコフシチナ村住民．５月12日入院．入院理由：放射能汚染．５月15日の放射線測定：衣服500マイクロレントゲン／時．甲状腺1200マイクロレントゲン／時．血液検査：白血球数2200．５月20日退院．

10．カルテ8011/554.（氏名略）男性21歳，ホイニキ市住民．５月23日，「放射能高汚染地域の滞在，血液検査の変化のため検査入院」．血液検査：白血球2500．甲状腺の放射線量130マイクロレントゲン／時．第１度の急性放射線症に対応する治療：グルコン酸カルシウム，レモン酸，総合ビタミン剤，ミネラル・ウォーター，イゾフェニン，胆汁排出剤．６月２日退院．

11．カルテ№ 8318/604.（氏名略）男性41歳，運転手，ホイニキ市住民．５月13日入院．肝臓の放射線量80マイクロレントゲン／時．甲状腺35マイクロレントゲン／時．血液検査：白血球2300，血小板14.4万．訴え：頭痛．

12．カルテ №7641/318.（氏名略）女性33歳，ポゴンノエ村住民．放射能汚染地域から入院．訴え：中程度の頭痛，口渇，苦味．５月６日の血液検査：白血球2200．５月７日の甲状腺1400マイクロレントゲン／時．

自律神経失調症：

13．カルテ№7868/533.（氏名略）男性64歳，ウラーシ村住民．コルホーズ「新生活」労働者（５月５日ストレリチェボ村へ避難）．５月20日地区中央病院入院．入院のときに全身衰弱，眠気，病気ぎみ，腰の痛みに対する訴え．病院へ送られてきた理由は，放射能汚染．居住の村は最高汚染地域．村での甲状腺放射線量は1.9～2.0ミリレントゲン／時．入院のときの甲状腺放射線量は３ミリレントゲン／時以上．５月27日の血液検査で白血球2900．６月５日退院．
　４月26日より５月５日まで患者は，４月28日に300ミリレントゲン／時が記録されているウラーシ村に居住，５月５日より15日までストレリチェボ村に滞在．

14．カルテ№7805/496/539.（氏名略）女性６３歳，ノボセルキ村．５月13日入院．入院理由：放射能汚染．放射線量：肝臓1000マイクロレントゲン／時，甲状腺3000マイクロレントゲン／時．患者は３日の間（５月10日より12日まで）原発から65㎞の野外に滞在．頭痛，吐き気，食欲不振，全身衰弱，病気ぎみ，眠気に対する訴え．５月19日の血液検査：白血球3200．５月27日退院．

15．カルテ№7795/491.（氏名略）女性59歳，ノボセルキ村住民．５月13日入院．入院理由：自律神経失調症．５月14日の衣服の放射線，700マイクロレントゲン／時．甲状腺2000マイクロレントゲン／時．頭痛，吐き気，のどのイガラに対する訴え．患者は原発から60㎞の野外で長時間を過ごした．５月21日退院．

16．カルテ№7818/495.（氏名略）女性49歳，ノボセルキ村．５月13日入院．病院へ送られてきた理由は放射能汚染．５月14日の衣服の放射線量900マイクロレントゲン／時，甲状腺3000マイクロレントゲン／時．５月10日に発病の徴候．原発から65㎞の所に滞在．衰弱，吐き気，食欲不振，頭痛に対する訴え．５月21日退院．

17．カルテ№7818/502.（氏名略）女性57歳，ノボセルキ村．５月15日入院．衣服のガンマ線量700マイクロレントゲン／時，甲状腺2600マイクロレントゲン／時．５月19日の血液検査，白血球2900．原発から65㎞の野外に滞在．自宅の家畜の牛のミルクを飲用．頭痛，衰弱，病気ぎみ，心臓部の痛みに対する訴え．

ベータ線による皮膚炎，やけど：

18．カルテ№7587/1060.（氏名略）男性35歳，ベリーキーボル村住民．５月４日入院．顔，手首の放射線やけどのため病院へ送られてきた．身体表面のガンマ線量300マイクロレントゲン／時，甲状腺700マイクロレントゲン／時．不快感，頭痛の訴え．

19．カルテ№7655/461.（氏名略）女性43歳，搾乳婦，ビソーカヤ村住民．５月６日23時入院．放射能による外傷（？），鼻血のため病院へ送られてくる．患者は５月１日より５日まで，チェムコフ村～ウラーシ村付近で牛の搾乳にたずさわった．５月５日，頭痛，吐き気，鼻血が出現．客観的症状：顔の皮膚，頸，手首の黒っぽい日焼け，頬が充血．血液検査：白血球3000．５月８日無断退院．

20．カルテ№7794/540.（氏名略）女性64歳，ノボセルキ村住民，５月13日入院．入院理由：放射能汚染．衣服のガンマ線1700マイクロレントゲン／時，甲状腺3000マイクロレントゲン／時以上．頭痛，吐き気，上腹部の痛みの訴え．チェルノブイリ原発から60㎞の所に居住．自宅の菜園で働いき，身体の外部に露出した部分が日焼け．５月26日の血液検査：白血球2800．５月29日退院．

神経・循環系失調症：

21．カルテ№8013.（氏名略）女性21歳，ホイニキ市住民．ブラーギン地区の衛生管理センターに勤務．５月23日入院．入院の１週間前から病気の兆候．患者は再三，高放射能汚染地域で働いた．頭頂部の激しい痛み，吐き気，衰弱，関節痛，心臓部の痛み，不眠，食欲欠如に対する訴え．６月２日退院．

22.カルテ№8060/550.（氏名略）女性49歳，ホイニキ市住民．５月23日入院．病気の徴候は５月３日に初めて発生．衰弱，吐き気が生じて，微熱．５月20日体温が39度に上がり，容体が悪化．頭痛，激しい衰弱，不快感，食欲欠如，吐き気，腰痛，頭頂部の痛み，口渇の訴え．

23.カルテ№7806/498.（氏名略）男性67歳，マレシェフ村（ホイニキ市のはずれ）．５月14日入院．入院理由：放射能汚染．甲状腺のガンマ線量1700マイクロレントゲン／時．血液検査：白血球2400，血小板10万．衰弱，頭痛，心臓部のうずくような痛みの訴え．５月21日退院．

咽頭部障害：

24．カルテ№7783/512.（氏名略）男性50歳，ボルシチェフカ村．５月12日放射能汚染の理由で入院．甲状腺のガンマ線量3000マイクロレントゲン／時以上．頭痛，から咳，気管入口のイガラの訴え．検査結果：口腔・咽頭粘膜の明白な充血．５月23日退院．

25．カルテ№7785/490.（氏名略），女性47歳，ネビトフ村．５月13日入院．理由：放射能汚染．原発から65kmの所に滞在．ソフホーズで働く．身体の露出した部分が日焼け．頭痛，衰弱，皮膜のむずがゆさ，口の焼けるようなひりひりした痛み，から咳に対する訴え．甲状腺放射線量300マイクロレントゲン／時． 血液検査：白血球2800，血小板14万．

26．カルテ№ 3637/363.（氏名略）女性36歳，ポゴンノエ村．５月５日入院．血液検査：白血球3400．甲状腺放射線量1400マイクロレントゲン／時．痛み，のどのイガラ，刺激感．５月12日退院．

甲状腺の高レベル被曝：

27．カルテ№8239/588.（氏名略）男性57歳，ロマチ村，巡回警備員．５月14日入院．甲状腺からのガンマ線量16ミリレントゲン／時．全身衰弱，口渇，頭痛の訴え．６月14日退院．

28．カルテ№8011/554.（氏名略）男性21歳，ホイニキ市住民．５月23日，医療衛生隊救護所から「放射線レベル測定不能（？）」との理由で転送されてくる．甲状腺のガンマ線量13ミリレントゲン／時．血液検査：白血球2500．

まとめ
　チェルノブイリ原発周辺の住民に急性放射線症がなかったという，IAEA（国際原子力機関），赤十字，WHO（世界保健機関）その他の見解を論理的に否定するためには，１件の症例（患者クリチェンコ）をあげれば十分である．しかし，患者クリチェンコのケースが単独で発生していたわけではない．もしボルシチェフカ村住民の１％に急性放射線症があったとすれば，マサーニ村，ウラーシ村などでは，その割合はもっと大きかったはずである．ホイニキ地区の30㎞圏からは5200人が避難したが，30㎞圏全体では10万人以上が避難した．われわれは1000件以上の急性放射線症があったと考えねばならない．

　これまでに明らかにされたデータは，1986年４月26日から27日にかけて放射線レベルが非常に高かったことを物語っている．この２日の間に，（野外での労働とか日光浴といった）特定の条件にあった人々は，100から300レムにも及ぶ被曝をうけることになった．休日（４月26日と27日）を過ごすために来ていた人々を加えると，その２日間に30㎞圏内で被曝した人々の数は，そこで暮らしていた住民の数よりかなり多かったことも明らかである．

さらに，４月26日，27日の非常に強烈な放射線状況は，30㎞圏から遠く離れた地域まで，とりわけ，日光浴をしたり自宅の菜園で働いたりしながら野外に長くいた人々がかなりの被曝をうけた可能性を示している．

1986年の４月から６月にかけて記録されたベラルーシ住民の病気とその特殊性を分析するにあたって，われわれはこうした要因を考慮する必要がある．
文献

1. V. Lupandin, "Invisible Victims", NABAT 36, October 1992. （和訳：「隠れた犠牲者たち」，技術と人間，1993年４月号）

2. 広河隆一，「チェルノブイリ：失われた医療記録」，現代，1993年９月号．

3. Los Angeles Times, April 14, 1992.

===============================================================

ヴァレリー・レガソフ

http://ja.wikipedia.org/wiki/%E3%83%B4%E3%82%A1%E3%83%AC%E3%83%AA%E3%83%BC%E3%83%BB%E3%83%AC%E3%82%AC%E3%82%BD%E3%83%95

ヴァレリー・アレクセーエヴィチ・レガソフ（レガーソフ、ロシア語: Вале́рий Алексе́евич Лега́сов、ラテン文字転写の例：Valeriy Alekseyevich Legasov、1936年9月1日 - 1988年4月27日）は、ソビエト連邦の化学者、ソビエト連邦科学アカデミー会員。チェルノブイリ原子力発電所事故の調査委員会責任者を務めた。

経歴
● ロシア西部のトゥーラで、労働者の家庭に生まれる
● モスクワのメンデレーエフ記念化学工科大学工業物理化学科を卒業
● ロシアの原子力研究の中心と位置づけられているモスクワのクルチャトフ原子力研究所で核燃料加工に関する卒業論文執筆
● シベリアの放射性化学工場で2年間勤務
● クルチャトフ研究所の大学院でいくつもの技術的プロセスの開発に携わる
● 1967年　博士候補
● 1972年　博士の学位を取得
● クルチャトフ研究所副所長、のちに第一副所長^[1]
● 1978-83年 モスクワ物理工科大学ru:Московский физико-технический институт教授
● 1981年　ソ連科学アカデミー正会員に選出される
● 1983年　モスクワ大学化学部化学工学科長 チェルノブイリ原子力発電所事故への対応
ソ連政府の事故調査委員会の中心人物であったレガソフは、隠さずに情報公開する姿勢が政府の反感を呼び、さまざまな問題に悩まされた。その間も放射線は彼の身体をむしばんでいった。
レガソフは、事故2周年にあたる1988年4月26日に、チェルノブイリ事故発生直後から災害防止の活動ぶりや住民避難を生々しく記述した告発文をソ連共産党機関紙 「プラウダ」 の幹部に極秘に手渡した。これはソ連の最高機密であった事故の真相をはじめ以下のような内容を含むものであった。
● 「チェルノブイリの事故について、私は明確な結論を下した。それは何年もの間続いてきたわが国の経済政策の貧困がこの事故を引き起こした、ということである。」
● ある原発幹部は「原発はサモワールのようなものだ」とうそぶいていた。
● チェルノブイリ型原子炉は欠陥炉だ、との指摘。
● 欧米の原発と比較して、装置の概念は基本的にはほとんど差異はないが、制御システムや診断システムが貧弱であること。
● 設備に多量の黒鉛、ジルコニウム、水が入っていること。
● 緊急時に作用すべき防護システムの作り方が異様であること。
● 感知器の一つからの指示で自動的に入るにせよ、手動でするにしても、緊急防護の制御棒を扱うことができるのはオペレーターだけ。
● 防護システムはオペレーターとは関係なく、装置の状況によってのみ作動しなければならないのに、そのように作動するシステムはなかった。
● 主要配管の継ぎ目を溶接するにあたり、正規の溶接法ではなく、手抜きの溶接をした。接続部分を検査した検査員による正しい施工を確認したとのサインがなされていた。
● 事故発生前日のオペレーター同士の会話記録。「マニュアルには、やることが色々と書いてあるのに、それらの多くが消されているが、どうしたらいいのか」という問いかけに対し、相手のオペレーターの返事は 「消された通りやればいい。」

翌4月27日、レガソフは自宅で遺体で発見され、一本の録音テープが残されていた。事故後に唱え続けた原子炉の安全対策が受け入れられずに絶望したなど、死の理由には諸説がある。
さきの告発文は同年5月20日付のプラウダで公表された。
1996年9月20日、エリツィン大統領はレガソフにロシア連邦英雄の称号を授与した。
イギリスBBCは、残された録音テープをもとにドキュメンタリー番組『チェルノブイリ原発事故』"Surviving Disaster: Chernobyl Nuclear Disaster" を制作、2006年1月24日に放映した。

外部リンク
YouTube動画 " Cleaning Up Chernobyl: Tragedy of Valery Legasov " 死後20年にあたってつくられた映像、ロシアトゥデイ2008年4月28日（英語）

最終更新 2014年2月20日 (木) 22:05

==============================================================

http://www.rri.kyoto-u.ac.jp/NSRG/tyt2004/annex-1.pdf

付録１： 本稿は1988 年5 月20 日付『プラウダ』に掲載され、「技術と人間」1988 年７月号、８月号に訳出された．

「これを語るのは私の義務･････」

Ｖ・レガソフ（松岡信夫・訳）


＜上＞
５０年の人生を生きただけだというのに、回想記を書かされるなど、私には思いもよらないことだった。けれどもあれほどの大事故が起きてしまい、真っ向から対立する利害を持ち、その事件の原因についてさまざまな異なる解釈を持つ多数の人たちが、事件のかかわりをもった。したがってここで私に求められているのは、あのできごとついて私が知り、理解し、見たことについて語ることだろう。

１９８６年４月２６日のことだった。土曜日ですばらしい天気だった。大学の研究室に行くのもやめて（土曜日は私が研究室に出る日だった）、また朝１０時から予定されていた党・経営活動者会議に行くのもよしにして、妻と友人とともに、どこかへ休息に出かけたいなどと思っていた。だが私の性格と、長年の間つちかった習慣からして、私は党・経営活動者会議へ出かけた。

会議が始まる前に、チェルノブイリ原発で事故が起こったことを聞いた。それを私に告げたのは、私たちの研究所を管轄している役所の幹部だった。かれはいまいましそうな口ぶりだったが、落ち着いて話してくれた。

会議の報告が始まった。正直に言って、その報告はきまり文句の、もう沢山というものだった。われわれの役所では万事順調でうまくいっている、業績指標はいいし、目標もりっぱに遂行している、といった報告には、馴れっこになっていた。報告は勝った戦闘の報告に似ていた。

原子力発電をほめたたえ、達成された大きな成果をうたい上げた報告者は、チェルノブイリで何か事故が起こったらしいことを、そそくさと付け加えた（チ原発は電力電化省の管轄だった）。「チェルノブイリで何かまずいことをしでかしたようです。事故だと言っていますが、それが原発の発展をおしとどめるようなものではありません」と言ったものだ。

１２時ごろ会議は中断された。私は二階の学術書記の部屋へ上がった。そこで私は政府委員会が設置され、私もその一員になったことを知った。委員は４時までにヴヌコヴァ空港へ集まるように言われた。

私はすぐに研究所にとって返した。誰か原子炉の専門家がいないかと思ったのだ。さんざん苦労した末、原子炉部長を見つけることができた。かれ―Ａ・カルーギン―はチェルノブイリ原発にあるＲＢＭＫ炉をもつ原発を開発し、運営したことのある人物である。かれもすでに事故のことを知っていた。というのは、夜中にチェルノブイリから「一、二、三、四」という暗号通信がとどいていたからだ。

これは原発で核、放射能、火災、爆発の危険が発生したこと、すなわちあらゆる種類の危険が存在することを告げる暗号だった。

私は研究所からすぐ帰宅した。妻も急いで仕事から帰ってきた。私は出張しなければならないこと、情況はまだはっきりしないし、向こうでいったい何が起こるのかわからない、と妻に言った。

ヴヌコヴォに着くと、シチュルビナ副首相が政府委員会の責任者に任命されたことを聞いた。かれは政府の燃料エネルギー問題本部長である。かれはその時、モスクワの外で、党・経営活動者会議を指導していた。かれが現われると、われわれはすでに支度のできあがった飛行機に乗り、キエフヘ飛んだ。キエフからは車で事故現場へ向かった。

機内では事故のなりゆきを案じる会話が交わされた。
私はシチエルビナ副首相に１９７９年米国のスリーマイル島原発で起こった事故のことを話した。といっても、スリーマイル島の事故原因は、チェルノブイリ事故には何の関係もなかった。両者の間には設備構造に基本的なちがいがあるからだ。ああだこうだと議論したり、臆測したりしているうちに、１時間の飛行時間が過ぎていった。

キエフに着き機外に出た時、最初に私の目を射たのは黒塗りの公用車の大群と、心配そうな表情を隠しきれない多数のウクライナの指導者たちだった。かれらは正確な情報をつかんでいないが、事態は思わしくないと語った。われわれは急いで車に乗り、原発へ向かった。正直に言っておかねばならないが、その時私の頭には、ポンペイの滅亡あるいはそれに匹敵する名だたる火山の噴火のように、人類の歴史に永遠に記録されるはどの地球的な規模の事件現場へ向いつつあるのだという意識はなかった。

上空は真紅の空焼けだった
その原発はチェルノブイリという名前だったが、実際は緑豊かで心なごませる農村型都市のチェルノブイリから、１８キロ離れたところにあった。その町はわれわれに心地よい印象を残した。そこでは静かで平和な日常生活がいとなまれていた。しかし、プリビャチ市に入ると、ここではもう不安が感じられた。われわれは市の中央広場に面した党市委員会の建物に着いた。地元の党・政府機関の幹部たちが出迎えてくれた。そこでの報告によると、第４発電所で規定を外れたタービンの慣性回転実験が行なわれていた。その過程で２回の爆発が起こり、原子炉建屋が破壊され、数百人が放射線を浴びたという。また２名が死亡し、他に市内の病院に収容されている者もあり、第４ブロックの放射線の状態は相当やっかいなものとなっていることが報告された。プリビヤチ市内の放射線の状態は平常のレベルを大幅に上回っているが、しかし、住民に大きな危険をもたらすまでにはいたっていなかった。

政府委員会はシチェルビナ副首相の独特の流儀で、大変精力的に会議を行ない、すぐに委員会の全員をいくつかのグループに分けた。各グループがその課題を解決しなければならなかった。
私が責任を負ったグループの課題は、事故を局部化するための対策を立てることだった。

われわれが原発に近づいていった時、空の様子にどきっとした。原発の８～１０キロ手前から、真っ赤な色の照り返しが目に入ったのだ。原発の設備やパイプからは、目に見える形では何も外部に放出されず、外見は非常に清潔できちんと整っているというのが常識である。ところが突然ここでは、金属工場や大化学工場と同じように、上空に真紅の大きな空焼けができているのだ。

事故現場には発電所の幹部とエネルギー省の幹部がいたが、かれらが矛盾した行動をしていることにすぐ気づいた。一面では発電所の多くの要員と幹部、エネルギー省の幹部は勇敢に行動していた。第１、第２ブロックの運転要員は職場を離れなかったし、第３ブロックで働いていた人たちも職務を放棄していなかった。第４号炉の建物の内部にさえ、さまざまな任務を実行する意思をもった人がいたし、どんな任務でもやりこなす人を見つけられる可能性があった（実際、それらの任務は遂行されたのだ）。しかし、４月２６日の夜８時、政府委員会がそこに到着するまで、どんな命令や任務をあたえて、状況をいかに正確に把握するかについてきちんと整った計画はまだできていなかった。そうしたことはすべて委員会がしなければならなかった。

まず第１に、第３ブロックが原子炉の運転停止と冷却を命じられた。第１、第２ブロックの内部では、放射能汚染がかなり高いレベルに達していたにもかかわらず、操業が続けられていた。第１、第２ブロックの内部汚染は、事故が起こったときすぐにスウィッチを切らなかったため、汚染された空気が室内に流れ込んできて生じたものだった。

黒鉛火災への対応策
シチュルビナ前首相はすぐにピカロフ大将が率いる国防省化学部隊、および空軍のヘリコプター部隊を呼び寄せた。かれらはきわめて迅速に現地に到着した。アントシキン少将がヘリコプター部隊の指揮をとった。飛行が始まり、第４ブロックの状態を空から観測した。最初の飛行で原子炉が完全に破壊され、原子炉室を覆っていた蓋は、吹き飛ばされて隅の方にほとんど垂直につっ立っているのが見えた。原子炉の蓋がこうまで空いた状態になるには、やはり相当な力が働いたことを思わせた。原子炉室の上部は完全にこわれ、機械室の屋上、原発サイトには黒鉛ブロックの断片――なかには原型をとどめているものもまじっていた――がころがっていた。

この破壊の特徴から見て、相当大きな爆発だったことがうなずけた。原子炉の上にあいた穴から、数百メートル上空までたえまなく白い煙が立ち上っていた。明らかに黒鉛の燃焼による産物である。原子炉の炉心内部には、白く光っているいくつかの大きな斑点が見えた。炉内に残った黒鉛が白熱してそう見えるのか、それとも黒鉛の燃焼で大量の炭素酸化物など、白味を帯びた物質が放出されているのが白く見える原因なのか、断定するのが困難だった。それでも空に照り返した色、それは黒鉛の高熱とそれが白熱状態にあることを示すものだった。

われわれの気をもませた第一の問題は、原子炉またはその一部が働いているかどうか、つまり半減期の短い放射性アイソトープの核分裂反応が続いているかどうかということだった。最初の測定は、あたかも強力な中性子の放射が存在しているかのような結果を示した。これは多分原子炉が働いていることを意味するものであった。

しかし、中性子の放射がないことを確信するためには、私は装甲車に乗って原子炉の近くまで行かねばならなかった。

４月２６日の夕刻までに、事故現場に放水して炉内の火を消し止めるあらゆる方法が試みられたが、いずれも役に立たなかった。ただ大量の蒸気が発生し、隣の第３ブロックに通じる各輸送通路が水浸しになっただけだった。

消防隊員は事故が発生した夜、機械室の火災の中心部を消しとめた。それはとても迅速で正確な仕事ぶりだった。消防隊員の一部が高い線量を浴びたのは、新しい火災の目が生じるのを監視するために、一カ所に立ち続けていたからだと言う人がいる。しかし、それはちがっている。機械室には発電機に大量の油脂、水素や線源があり、火災だけでなく、爆発を誘引するような物質が沢山
あった。爆発すれは第３ブロックの破壊は免れなかっただろう。

こうした具体的状況の下で消防隊員たちがとった行動は、英雄的であったばかりか、正しい、その場に適した、有効なものだった。かれらは事故を局所化し、その拡大を防ぐための、最初の正確な措置をとったのである。

次の問題は、破壊された４号炉の開口部から、放射性微粒子の強い流れが放出されていることが明らかになった時に生じた。黒鉛が燃焼して生じた粒子が、かなり多くの放射能を運び出すのだ。困難な任務ができた。黒鉛の通常の燃焼速度は１時間でおよそ１トンである。４号炉には約２５００トンの黒鉛が積んである。したがって黒鉛が２４０時間通常の速度で燃えれば、放射能が広い
地域に拡散し、強度に汚染されることになる。

水、泡、その他の消火材で黒鉛の火を消しとめる適当な方法はなかった。原子炉の上空２００メ－トル以上のところからだけ、有効な手を打つことができる。いずれにせよ、これまでにない新しい解決方法をさがさねばならない。それについて考えはじめた。われわれはたえずモスクワと連絡をとりながら考えを進めていった。モスクワ側にはＡ・アレクサンドロフ（クルチャートフ原子力研究所所長）、原子力研究所の同僚たち、それにエネルギー省の専門家たちが控えていた。翌日早くも諸外国から、さまざまな混和物を使って黒鉛火災を鎮火させる方法が、電報で提案されてきた。

それらを検討し、何度も相談を繰り返した結果、温度の安定剤として二つの物質－－鉛とドロマイトが選ばれた。

避難決定のいきさつ政府委員会が解決したさらに重要な問題は、プリビャチ市の運命に関するものだった。４月２６日の夜、市内の放射線は毎時１から数１０ミリレントゲンが測定され、それほど心配の要らない状態だった。もちろん、これは決して健全な状態ではなかったが、しかし、まだ何らかの対策を考えるゆとりは残されていた。一般人の被曝線量が２５レム／人になる危険がある時に、避難を開始できるという規制があった。被災地域に滞在中に被曝線量が７５レムになると、避難を義務づけられる。２５～７５レムの間で避難を決定する権利は地元機関がもつ。まさにこうした事情の下で議論が行なわれた。放射線状況の変動がよい方向へ変化しないことを予感した物理学者たちは、避難が必要であることを強く主張した。医学者たちはこの場面で物理学者たちに譲歩した。４月２６日の夜１０時か１１時ころだった。われわれの議論に耳を傾けていたシチェルビナ議長は物理学者の予測を信じて、強制避難の決定を下した。

避難は翌日実行された。この情報は口コミや掲示によって広められたが、残念ながら全員にゆきわたらなかった。というのは４月２７日の朝、町の通りでは乳母車を押す母親や遊んでいる子どもたちの姿が見えた。それはふだんの日曜日の風景と変わらなかった。

午前１１時、全市民の避難が正式に発表された。午後２時に必要なバスがそろい、バスの進路が定められた。

避難はかなり正確かつ迅速に実施された。異常な事態の中で、予期せぬタイヤのパンクだとか、予定外のことがあるにはあったが……。たとえば相当数の市民が政府委員会に対して、マイカーでの避難を申請してきた。市内には数千台の自家用車があった。しばらく考慮した後、それは許可されたが、自動車が汚染されていることを思うと、その決定はやはり正しくなかった。しかし、放射能汚染の測定所と車輌の洗浄地点が設けられたのは、それより後のことだった。

まあくり返して言うが、避難が実行された時点で、市内の汚染のレベルはまだそれほど高くなかった。これは後でわかったことだが、事故当時原発にいた者を別として、約５万人の市民のうちでなんらかの重大な健康障害を受けた者はいなかった。

次の対策はより綿密な放射線測定管理を実施することだった。この仕事は国家水文学気象委員会、ピカロフ大将指揮下の化学部隊、原発の勤務員、物理学者たちによってなされた。放射性物質の組成も詳細に研究された。

軍隊の放射線測定隊もなかなかよくやってくれたが、放射性物質の組成、その活動分布の特徴について最も正確な情報を提供してくれたのは、被災地域に設置された研究室だった。そこから得られるデータに基づいて、対策が決められた。

それにしても最初の何日間かは、空気の動きの変化、４号炉の燃焼とそれにともなう物質の放出にともなって、状況はたえず移り変わった。

いくつかの〝ひどい話〃その当時のことについて、いくつかの個人的な印象を語っておきたい。

まず発電所の所員のことから。われわれはいついかなる時でも、どんな任務にも応じられる用意をしておくことを、人びとに求めた。けれどもあの状況下で、仕事の計画を立て組織化するといったことに対応できる能力をもった者は、原発の幹部にも、エネルギー省の指導部にもいなかった。あらかじめ書かれた指示も参考文献もなしに状況を判断し、必要な行動を指示する機能を負わねばならなかったのは、政府委員会だった。

あきれるほどこまごまとしたことにまで気を使わねばならなかった。政府委員会がプリピャチ市に着いたはじめのころ、放射能防護マスク、個人用線量計が必要な数だけそろっていなかった。あのあまり信頼できないエンピツと呼ばれていた線量計、全員に渡るだけの数がなかった。またチェルノブイリ原発には、周辺数キロ範囲の放射線レベルを自動的に測定記録する装置さえなかった。

したがって測定データを得るために、多くの人を組織しなければならなかった。放射線測定器を積んだ無人飛行機もなかった。そのため測定・探査飛行のため相当数の飛行士が必要だった。

ひどい話だが、最初のころは基本的な衛生知識さえもなかった。４月２７、２８、２９日といえば、プリビャチ市内の家の中はすっかり汚れているのに、ソーセージ、キウリ、びん入りペプシコーラ、ジュースなどが部屋の中にむき出しで並べられ、人びとはそれを裸の手でつかんだり、切ったりしていた。状況が多少とも正常になったのは、何日か後になってからのことだった。その時には食堂、売店に、非常に原始的なものだったが衛生施設がととのい、汚れた手や食物を少なくとも洗うことができるようになった。

くい違う情報の調整
５月２日、政府委員会がチェルノブイリへ移転した日、ルイシコフ首相とリガチョフ政治局員が現地を訪れた。

かれらの訪問は大きな重要性をもっていた。かれらは党チェルノブイリ地区委員会で会議を開いた。われわれの報告（私自身が主報告をすることになった）から、かれらは状況を把握し、これが部分的な事件ではなく大規模事故であり、きわめて長期的な影響をもち、巨大な仕事が待ち受けていることを理解した。

状況説明の報告が終わり、かれらが事情を掌握した後、今後の活動予定、規模、全省庁と企業のかかわり方などを定めた重要決議が採択された。ルイシコフ首相の指導下に作業グループが作られ、ソ連の全工業が事実上そのグループに編入された。その時点から政府委員会は、ソ連共産党中央委員会政治局の作業グループの指導下で行なわれる、大きな国家的活動を具体的に管理する機構になった。

私は政治局の作業グループの視野をはずれたような大小のできごとを、一つとして知らない。同グループの会議と決定は非常におだやかな、控え目なもので、いろいろな専門家の見解を並べてさまざまに対比しながら、専門家の視点に依拠しようと最大限努めていたことを、言っておかねばならない。それは私にとっては、正しく組織された仕事とはこういうものだ、という見本であった。

第一そこでは状況を少しでも早く制御し、発生した事態を緩和するためならば、自由に決定し取り組むことができた、と言うことができる。こんなことはかつてなかった。作業はすぐれた科学研究集団の中でやるように組織された。

第一にさまざまなところから流される情報、希望的な情報を注意深く分析した。軍隊から提供される情報が、民間の科学者から提供される情報とくいちがっていることがしばしばあった。もっとも初期段階では科学者のグループの方でも、グループごとにちがった情報を提供したものだったが。こうしたことでかなり神経のくたびれる状態が生まれた。しかし、政治局の作業グループ自体はそうした神経過敏の様子を見せたことがなかった。同グループはいつでも放射線の状況をはかり直し、正確なデータを入手し、ものごとの真実の状態をつかむよう努力した。しかも作業グループは何かを決定する場合には、人びとの利益をできるだけ守るよう努力した。たとえば汚染地帯は実に変化に富んだ分布を示したが、避難民たちが必要とした補償金の額は事故の被災者たちに有利に決められた。一事が万事、そういうふうに運ばれた。

除染作業に活躍した軍
軍隊の活動について若干述べておきたい。軍隊の活動範囲は非常に大きなものだった。先ず第一に化学部隊は放射線の状態を調査し、汚染地域を特定する作業をしなければならなかった。原発サイトでも、３０キロ・ゾーンにおいても、樹木、住宅、道路の除染作業は軍の双肩にかかっていた。軍隊はプリビャチ市の除染という大仕事をやりとげた。

軍または民間の専門家の中で、自分の仕事をいいかげんにしたり、困難で危険な仕事にむりやり参加させられたと感じている者を、一度も見たことはなかった。私自身も第４ブロックのきわめて危険な区域に何度も足を運んだ。私は人とに状況をありのままに説明し、自発的に私を助けたいと思う人とだけ、共同作業したいと言った。それを開いてしりごみしたり、志願するのをやめる
者は一人もいなかった。（続く）

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わが国には原子力出版所、医学文献出版所、「ズナーニエ」（知識）協会などがあるにもかかわらず、次のような問題について住民の間に手早く広め、説明できるような出来合いの文献が、まったくなかったことが明らかになった。すなわち人が比較的安心できる被曝線量、きわめて危険な被曝線量、放射線の危険性が高まっている地域に人がいる時、どのように行動すればいいのか、何をどのような方法で測り、野菜、果物などをどう取り扱えばいいのかについて、心得をあたえることができるような本である。部厚くて、中身の詰まった、正確な内容の専門家のための書物は沢山出されたが、しかし、いま述べたような手軽な小冊子、パンフレット類は事実上ないにひとしかった。

ソ連での原子力開発に思うさて、ここらでそろそろ、いかなるいきさつで私がこんな物語をする羽目になったのか、私とこの物語とのかかわりについて、また原子力開発の歴史とその特質とをいかに理解していたか、現在それをどう考えているかについて、若干の個人的な感想を述べる時がきたように思う。われわれの仲間でこのことに関して、本当に心を開いて、しかも正確に語った人はほとんどいなかったのではなかろうか。

私はメンデレーエフ記念モスクワ化学工科大学の工業物理化学科を卒業した。この学科は専門家、主として原子力工業技術部門で働くべき研究者を養成していた。つまり同位体分離作業や放射性物質の取り扱いができ、鉱石からウランを取り出し、それを必要な規格に仕上げ、それから核燃料を作ることができ、すでに強い放射性成分を含んでいる使用済み核燃料を再処理し、それによって利用可能な核分裂生成物質と危険な毒性物質を分離することができ、それが人間に害をもたらさないように処理処分できる技能をもった人材の養成である。いうなれば国民経済や医学のために、放射線源を有効利用することである。こうした多くの専門的な問題について、私は教育をうけたのだった。

その後私はクルチャートフ原子力研究所で核燃料加工に関する卒業論文をまとめた。Ⅰ・Ｋ・キコイン・アカデミー会員は、私の卒業論文が気に入り、私を大学院に残そうとした。しかし、私は仲間たちとともに、原子力産業の関連工場である期間働き、将来自分の研究対象となるような分野である程度の実際的経験を積むことを約束していた。そういう考え方を煽ったのは他ならぬ私自身であり、その当人が大学院に進むようにとの提案を受け入れるわけにもいかず、私はシベリアへ発ったのだった。そこで私はある放射性化学工場の運転開始に参加することになった。この現場への参加は、とても活気のある、面白い時期だった。そのエ場で２年間働いた後、私はやはりクルチャートフ研究所の大学院に「引き戻された」のだった。

私はそこでいくつもの技術的プロセスの開発にたずさわり、博士候補および博士の学位を得た。私はソ連科学アカデミー会員に選ばれ、研究成果を評価され、国家賞を授与された。それらはすべて私の専門的な活動である。

そうした活動に私はきわめて興味深い若者たちを引きつけることができた。よい感覚をもち、高い教養と豊かな理解力を備えた若いかれらは、今日までこの化学物理の分野を発展させてきたし、またそこから実用のためにも、事物の認識過程にとっても、多くのきわめて重要なことが生まれるものと、私は確信している。

この分野の活動の成果が注目を集めたものとみえて、私は研究所の副所長になった。その際、研究上の任務は、私自身の固有の研究課題に限られていた。私の職務分掌には、当時も今日までも変わりはないのだが、化学物理、放射線化学および工業目的の核とプラズマ源の利用に関する諸課題が入っている。Ａ・Ｐ・アレクサンドロフがソ連科学アカデミー総裁に選ばれて後、彼は私を研究所の第１副所長に推挙した。

私はソ連のエネルギー利用において、原子力が占めるべき比重、またそれが存在すべき理由について、関心を抱いていた。所定の目的のためにどのようなタイプの発電所を建てるべきか、それらをいかに合理的に利用するか、それらは発電だけにとどめるか、それとも水素など他のエネルギー源も生産すべきか、といった事柄に関するシステム的な研究を組織することもできた。それ以降、私は水素エネルギー利用の分野に、たえず目を配ってきた。これらはすべて、原子力を補完する異色の問題だった。

核エネルギー利用の安全性の問題が世界的な世論のさまざまな場で、最も鋭い論議の対象になっているため、当然私は原子力発電がともなう現実の危険性、現実の脅威を、それ以外の発電システムがもつ脅威と比較対照することに関心を持った。私はこの問題に熱心に取り組み、主として原子力に代替するエネルギー源の危険性の解明に力をそそいだ。

研究所の科学技術会議ではきわめて頻繁に、原子力利用の発展についての概念的問題は討議されてきたが、しかし、技術的な側面、つまりあれこれの原子炉の品質、燃料の品質といったことが取り上げられることは極端に少なかった。これらの問題も科学技術会議で討議されることはあった。にもかかわらず、私が得ている情報によると、原子力利用を発展させる仕事は、万事順調にいっているわけではないように思えた。素直な目で見れば、ソ連の機器はたとえば概念の上では、西側のそれと原理的にほとんど変わっていないし、一部の問題では西側よりすぐれているようにさえ思えたが、しかし、制御系や計測系は貧弱だった。

米国のラスムッセンは原発の安全解析を行ない、事故に結びつくあらゆる可能な異常事象源を順次見つけ出し、それらを系統立て、あれこれの事象の確率評価を行なった。つまりある事象がどんな確率で、外部への放射能漏れを起こすかを評価したのである。私たちはこのことを外国の文献から知ってはいた。だがソ連国内でこれらの問題について多少とも専門的に問題を提起し、検討したグループを私は知らない。

わが国で原子力利用の安全性について、最も積極的に発言してきたのはＶ・Ａ・シドレンコだった。かれの態度は真剣なものに思われた。かれは発電所の運転、製造された設備の品質、時として遭遇する異常などに関する実際を熟知していた。しかし、かれの努力は主としてこれらの異常を、第一に組織的な方策、第二に発電所および設計者が常備すべき文書の改善システムによって、解決することに向けられ、また第三には状況を管理する監視機関の創設に大変苦労していた。

かれとその同調者たちを非常に心配させていることに、発電所に納入される設備の品質問題があった。最近は誰もかれもが、原発を設計し、建設し、運転する要員の教育と訓練について、心配するようになった。設備の数は急激に増加したのに対して、そのプロセスに参加する要員の訓練度は逆に低下しているからだ。Ⅴ・Ａ・シドレンコは、これらの問題に関する指導者だった。残念ながら、かれは当然受けてしかるべき支持が得られなかった。

一片の書類を書き、一歩前に進むことが大きな苦痛をともなった。
心情的にはこれも理解できることだった。なぜならわれわれが働いていた役所は、原理的には、いかなる業務をも遂行できる最高の資格を有する人びとによって構成され、最高の責任をもたされていたからである。実のところ、熟達した人たちの手中にあれば、ソ連の設備機器も信頼ができ、安全に、運転されるように思えたものだった。原発の安全性向上についての不安は、こじつけた問題のように思われた。というのは、これは高度に訓練された専門家の世界のことであり、かれらは安全性の問題は熟練度と要員に対する指示の正確さによって、専ら解決できるものと信じていたからである。

原子力利用と直接関係のない設備の創設に、ますます多量の資源が費やされるようになった。燃料要素の製造設備、金属学関連の設備が作られ、役所の課題と関係のない施設を作るために、大量の建設資材が費やされた。

かつてはこの国で最強を誇った研究組織が弱体化しはじめ、近代設備の設備水準が低下し、要員の高齢化がはじまり、そして新しい方法は歓迎されなくなってきた。仕事のリズムがしだいに習慣化し、あれこれの問題解決の仕方がマンネリ化するようになった。

私にはこれらすべてのことが見えてはいたが、こうした成りゆきにとくに専門的に口をはさむのは難しいことだったし、こうした事柄についての一般的な意見というのは敵意をもって迎えられるのがおちだった。なぜなら専門外の者が、専門家の仕事に何らかの考え方を持ち込むことなど、到底受け入れられるところではなかったからだ。

自分の仕事に熟練はしているが、機器やその安全性を保障するシステムについては、批判的に対処しない技術者の世代か増えた。私は猜疑心に苦しめられた。というのは、私の専門的な視点からすれば、何か新しいことをしなければならない、方向を変えてこれまでとはちがったやり方を試さなければならないと思えたからだ。

私はこれまでかなり大きな危険を冒してきた。これまでの人生で１０件の研究用原子炉レベルのプロジェクトを行なってきた。そのうちの５件は失敗し、国家に２５００万ルーブル（訳注・約５０億円）の損害を及ぼすことになった。それらが失敗したのは、出だしからまちがっていたからではなかった。それらは心をとらえるような、興味深い仕事だったが、必要な資材がなかったり、あるいは、たとえばいくらか手のこんだコンプレッサーとか熱交換機とかの開発を引き受けてくれる組織がなかったりして、最初の興味深いアイデアが計画段階で高価で膨大なものになり、ついには最後まで実行されないまま終わってしまった。１０件のうち２件は、同じょうな理由で同様の運命が待っているのではないかと案じている。しかし３件は大きな成功をおさめた。よいパートナーが見つかったところでは、成立した３件の仕事のうち１件だけでも、投入した１７００万ループルの資金に対して、今日までまだうまくいっていない研究用原子炉に使った２５００万ルーブルに利息を払って、なおお釣りがくるほどの利益を毎年あげるようになっている。それでもなお私の仕事のリスク度はかなり高い方で、５０～７０％の範囲にある。
原子炉の分野では同じようなことを私は知らない。

原子力開発体制の欠陥
伝統的な原子炉建設は、なぜか私にはほとんど興味がなかった。もちろん、その危険度がどれ位のものか、当時としては想像もしなかった。不安な気持ちはあったものの、それでもまだ「しっかりした人たち」がいたし、大きな企業と経験に富んだ人材が揃っていたので、かれらがまさか異常を見逃すなど、思いもよらなかった。西側の機器とわが国のそれを比較検討することによって、現存の機器に安全上の問題は沢山あるとしても、なおかつそれらは伝統的な発電所より危険は少ないという結論を出すことができた。後者は大量の発ガン物質を大気中に放出し、石炭層からは放射性物質を大気中に放出しているのである。

RBMK 炉についていえば、原子炉関係者の間ではできの悪いものと考えられていた。できが悪いと考えられたのは、安全設備のせいではなかった。安全設備の点から見れば、それはむしろよい方に属していると判断された。

悪かったのは経済性、燃料の大量消費、投下資本の大きさ、その設備が工業的基盤をもたないことなどについてであった。これらの機器で多量の黒鉛、ジルコニウム、水が使われていることが、化学者である私には心配だった。極限的な状況で作動すべき防護システムが、私の見たところ異常なほど不十分な作りであることも気がかりだった。つまり、非常用制御棒は、センサーの一つからの信号で自動的にか、または手動でか、運転員が挿入できるだけだった。機械というものはうまく働くこともあれば、働かないこともある。運転員から独立して、機器が設置された場所の状況と無関係に作動するような、他の防護システムはなかった。私は、専門家たちが事故防護システムの変更を設計者に提案した、という噂を耳にした。その提案は拒絶はされなかったものの、その開発は遅々としたものだった。

私は自分が信じているが、同僚たちとは意見を異にし、したがってわれわれの間で摩擦を起こしている視点について、話しておきたいと思う。西側には、ソ連の航空機産業や、発達した工業部門における「科学指導者」や「設計者」という概念がないということである。たとえば、航空事業を発展させる戦略問題についての科学指導部が存在し得ることは認めよう。しかし、飛行機の設計についていうならば、そこには一人の主人がいなければならず、それが設計者であり、計画立案者であり、科学指導者であり、権力と責任はすべてその手中になければならない。これは私には自明のことに思えた。

原子力利用がはじまったはかりのときは、誰もが理性的だった。これは核物理、中性子物理など、新しい科学の分野であったため、科学指導部という概念は、機器建造の基本原理は設計者にゆだねられるということになったのだった。科学指導者はこれらの原理が物理的に正しく、物理的に安全であることに、責任をもった。一方、設計者はこれらの機器の建造が物理法則に反していないかどうかを、物理学者らと常に協議しながら、これらの原理を実現した。原子力産業が生まれたばかりのころは、これらすべてのことが実現されていたのだ。だが設計組織が成長し、かれらが独自の計算、物理部門をもつようになると、同じ一つの機器に対する二重権力（実際には、官庁内および官庁間の数多くの審議会があるので三重権力）の存在により、機器の品質に対する集団責任体制が作られた。こうした状況は今日でも見られるが、私に言わせれば、それは正しいことではない。私は依然として科学指導者機構というのは、あれこれの計画に専門的な検討を加え、そのなかからすぐれたものを選び、原子力を発展させる戦略を定める機構だと信じている。そこにこそ科学指導者の機能があるのであり、特定の性質を備えた具体的な機器を造ることに、その機能があるのではない。これらすべてのことがごちゃまぜになり、機器の品質に対する個人的責任が欠如したシステムが出現したことが、重大な無責任体制をもたらしたのであり、またチェルノブイリの経験がそのことを示したのだった。

Ｎ・Ｉ・ルイシコフ（ソ連首相）は、７月１４日の会
議の発言で、チェルノブイリ原発事故は偶然のできごとではなく、原子力発電は一定の不可避性を持ってこうした重大なできごとに向かっていたように思われる、と述べた。当時、私自身は問題をそのように定式化することはできなかったが、私はそのことばの正確さに心を打たれたものだった。私はある原発の主配管を溶接継ぎ目に沿って正しく溶接せず、溶接工が簡単に電極を取りつけて、上から軽く溶接していたケースを思い出した。大口径配管の破断、冷却水の完全喪失や炉心溶融などをともなうＲＢＭＫ炉の大事故が起こったかも知れない。要員が訓練された注意深くて正確な人だったからよかったが、運転員が見つけた孔は、顕微鏡でも見えないほどだったのだ。審理がはじまり、これは単に配管の溶接がいいかげんになされただけと説明された。書類の検査もはじまったが、そこには必要な署名がすべてそろっていた。上質の継ぎ目溶接をしたという溶接工の署名、自然には存在するわけのない継ぎ目を検査したという非破壊検査負の署名があった。すべてこれらのことは、継ぎ目をより多く溶接するという労働生産性の名においてなされたのだった。このずさんな仕事は、われわれの想像に一撃を加えた。後に多くの原発で該当箇所の検査が行なわれたが、結果はすべてのところで良好というわけではなかった。

しばしば重要な連絡に欠陥があったり、不良動作でＲＢＭＫ型炉の配水管構造から弁がはずれたりということは、毎年のように起こっていた。訓練の必要については１０年間も話されてきたし、装置状態の診断システムを作ることについては、少なくとも５年越しに議論が交わされてきたが、何一つ実行されなかった。技術者および原発の運転にかかわるその他の要員の質が、しだいに低下してきたことが想起される。原発の建設現場に行ったことのある誰もが、こんなにも重要な現場でこんなにもいいかげんな仕事がされていることに、おどろいたことだろう。すべてこれらのことは個々のエピソードとして頭の中にあったのだが、Ｎ・Ⅰルイシコフ（首相）が原 子力発電はチェルノブイリへの道を進んでいたと述べたとき、私の限前にこれらすべての情景が現われ、原発建設分野で起こるすべてのことに、きわめて具体的に、きわめて慣習的に対処していた私自身のいる研究所の専門家たちが、眼前に立ち現われたのだった。

これは私の性格の特徴に由来することだが、私はこの問題を、より注意深く研究しはじめたし、またあちこちで以前に増して積極的に、次世代の原子炉はより安全な高温ガス冷却炉または溶融塩炉でなければならないという立場を取り、そう発言するようになった。これは異常に激しい怒りを呼び、それはまったく別の事柄だとか、私は何も分かっていない人間だとか、他人の領域に口を出すだとか、ある型の原子炉を他の型と比較してはいけない、などと言われたものだ。状況はこんなにも難しかった。代替原子炉の開発も静かに進められていたし、現在の原子炉にもそれとは言わずに改善が加えられていた。

が、最も残念だったのは、事柄の真の状態に関する真剣な、客観的な、科学的な分析がどうしてもできないことであり、できごとのサイクル全体を組み立てて、起こり得るすべての異常を分析し、それを避ける手段を見つけることができなかったことである。チェルノブイリ事故の前夜、事態はこのように進み、しかも、原発設備の各種部品の製造を委託されている企業の数も増加していた。

アトムマシ（注：原子力機械製造企業、ポルゴドンスクに工場がある）の建設がはじまり、多くの若者がそこにおもむいた。工場の建設には大きな失敗をともなった。

自らの職業的専門性を高めるべき専門家の質には、改善すべき余地が多く残されている。このことは原発においても同様だった。

チェルノブイリ原発の事故処理に従事した後、私は次のような明解な結論に達していた。すなわち、チェルノブイリ事故はドラマの結末であり、数１０年にわたってわが国で行なわれてきた生産施設の誤った運用の頂点に位置するものだった。もちろん、チェルノブイリで起こったできごとには、抽象的でなく、具体的な責任者がいる。われわれは今日すでに、この原子炉の防護管理システムに欠陥があり、それは、それは多くの科学者には周知のことであり、かれらはその欠陥を除去する提案をしていたことを知っている。早急に余分の仕事をすることを欲しなかった設計者は、防護管理システムの変更を急がなかった。

チェルノブイリ原発で長年の間行なわれてきたのは、きわめてぞんざいに、不正確に作られた計画による実験の実施であり、実験開始前に起こり得る状況についての洗い出しもまったくなされなかった。設計者や科学的指導者の意見に対する軽視がゆきわたっていたので、すべての技術的規則を正しく遂行するために、大いに努力する必要があった。定期点検が行なわれるまで、機器や設備の状態に対する注意はまったく払われなかった。ある原発の所長が率直にこう言ったことがある。「何を心配しているんですか？原子炉なんてサモワール（ロシアの湯沸器）ですよ。火力発電所よりはるかに簡単です。経験に富んだ要員がいますし、何も起こっちゃいませんよ。」 事故の一連の経過を眺め、なぜあの人がああふるまい、この人はこうしたかを見てみると、罪を犯した責任者、事件のきっかけを作った人を、ただ一人に特定することはできない。なぜならばそれは両端が閉じられた鎖だからである。運転員たちは実験を必ずやりとげようとして過ちを犯した。かれらはこれを「名誉なこと」と考えていた。実験実施計画は大変質が低く、大ざっばで、専門家の承認を得る必要があったにもかかわらず、それを得てはいなかった。私の金庫には、事故発生前夜の運転員たちの電話による会話の記録が保管されている。この記録を読んでみると、背筋が寒くなる。

ある運転見が別の運転員を呼び出して尋ねる。「この計画にはやるべきことが書かれているが、後から多くの部分が消されている。いったいどうしたものかね？」そうすると相手は少しばかり考えた後、「じやあ、消してあるとおりにやればいい」と答える。

原発のような施設における重要文書の作成水準がこれなのだ。誰かが何かを削除する。運転員は削除部分が正しいか正しくないかいずれにも解釈でき、好き勝手な行動をとることができたのだった。といって、すべての罪の重さを、運転員にかぶせてしまうことはできない。なぜなら、誰かがその計画を作成し、その中のどこかを削り、誰かがそれに署名し、そして誰かがそれに同意しなかったのだから。原発の要員が、専門家の承認を得ていない何らかの行為を、自分だけの判断でなし得るという事実そのものが、この発電所と専門家の関係における欠陥なのである。発電所に国家原子力発電安全運転監視委員会の代表が駐在していたという事実、しかし、行なわれる実験の過程にも、計画作成の経過にも立会わなかったという事実、これは単にこの発電所の履歴上の事実だけではすまなくなるのである。

ふたたびチェルノブイリヘ
話が余りにも脇道へそれてしまったので、もう一度チェルノブイリのできごとに戻ることにしよう。空軍、ヘリコプター部隊は実に正確に働いた。これは高度の組織性を発揮した手本だった。あらゆる危険を無視し、すべての乗組員がいかに困難かつ複雑な任務であろうとも、常にそれを遂行すべく努力した。最初の日々はとくに困難だった。砂入りの袋を投下せよとの命令が出された。

なぜか地元機関は袋と砂を準備するのに十分な人数を、ただちに組織することができなかった。乗組員の若い将校が、砂袋をヘリコプターに積み込み、飛び立ってそれらを目標に投下し、舞い戻ってきて、再び同じ作業をするのを私はこの目で見た。もし私の記憶に誤りがなければ、その数は最初の一昼夜に数１０トン、次の３日目（昼夜）では数百トン、最後にはアントシキン少将が夕刻の報告で、一昼夜に１１００トンの資材を投下したというまでになった。

５月２日までに原子炉は事実上密封された状態になり、それ以後、炉心から放出される放射性核種の総量はいちじるしく減少した。

５月９日ごろ、第４ブロックは呼吸を止め、燃えつき、生きるのを止めているように見え、外見はおとなしくなったようだった。われわれは勝利の日（注＝５月９日は大祖国戦争の勝利をおさめた記念日）を迎えて、夕方からお祝いをしようとしていた。だが残念ながらまさにこの日、小さいがしかし明るく輝いている暗赤色の点を、第４ブロックの内部に発見したのだった。それはまだ高温が保たれていることをもの語るものだった。鉛やその他の資材を包んで投下したパラシュートが燃えているのか、判断が困難だった。私の見解ではこれはそんなことではなく、むしろ灼熱した砂、粘土、その他の投下物だった。祝日は台なしになり、そのかわり原子炉の穴にさらに８０トンの鉛を投下することが決められた。その後、光を発するものが消え、われわれは５月１０日にやや落ち着いた状態のなかで勝利の記念日を祝ったのだった。

当時すでに、あの重苦しい日々にあって、逆説的なことだが、われわれは高揚した気分になっているようだった。その気分は、これほど悲劇的な事件の処理に参加しているということと、結びつくものではなかった。基調をなしていたのは悲劇性であり、すべてはそのトーンで進んだ。しかし、人びとがあんなにまで働き、われわれの要請にあんなにまで反応があり、さまざまな技術的対策があんなにもはやく計算されたことが、ある種の高揚した気分を生み出し、われわれはすでにその場で、崩壊したブロックの上に築かれる円屋根の、最初の設計の計算をはじめたのだった。

（記録はここで中断されている：訳者）
（まつおかのぶお、市民エネルギー研究所）

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The Mystery of Valery Legasov Death HD Part 1 - 3

)

アップロード日: 2011/10/29

The Mystery of Valeri Legasov. El Misterio de la muerte de Valeri Legasov.

Valeri Alekséyevich Legasov (Валерий Алексеевич Легасов; 1 de septiembre de 1936, Tula, URSS — 27 de abril de 1988, Moscú, Unión Soviética) fue un prominente científico soviético en el campo de la química inorgánica, un miembro de la Academia de las Ciencias de la Unión Soviética. Es famoso por su trabajo a cargo del comité de investigación del desastre de Chernobyl del 26 de abril de 1986. Se suicidó en 1988, justo 2 años después, víctima de una depresión provocada por la exposición a la radiación, por la falta de reconocimiento internacional de la catástrofe y por la pérdida de vidas humanas.

Valeri Alekséyevich Legasov (Валерий Алексеевич Легасов;
September 1, 1936, Tula, USSR - April 27, 1988, Moscow, USSR) was a prominent Soviet scientist in the field of inorganic chemistry, a member of the Academy of Sciences of the Soviet Union. It is famous for his work by the research committee of the Chernobyl disaster of April 26, 1986. He committed suicide in 1988, just 2 years later, a victim of depression caused by exposure to radiation, lack of international recognition of the disaster and the loss of human lives.

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The Mystery of Valery Legasov Death HD Part 2 - 3

)


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The Mystery of Valery Legasov Death HD Part 3 - 3

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Cleaning Up Chernobyl: Tragedy of Valery Legasov



アップロード日: 2008/04/28

Its been exactly twenty years since Valery Legasov -- one of the Soviet Union's highly acclaimed scientists -- committed suicide. He headed the scientific group involved in the clear-up of the Chernobyl blast in 1986 and threw himself into finding what caused the disaster. However he met a lot of difficulties in his path, which - as some say -broke him . Russia Today's Alexey Yaroshevsky brings an XL report about Valery Legasov's life.

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CHERNOBYL DISASTER: Valery Legasov's battle, part 1

)

アップロード日: 2011/01/22

Valery Legasov, one of the Soviet Union's highly acclaimed scientists, headed the scientific group involved in the clear-up of the Chernobyl blast in 1986. He threw himself into finding what caused the disaster. He met a lot of difficulties in his path, which broke him: in 1988 he committed suicide.
Filmed in 2008.

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CHERNOBYL DISASTER: Valery Legasov's battle, part 2

)

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BBC Surviving Disaster Chernobyl Nuclear Disaster 2006



公開日: 2012/10/17

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アラ・ヤロシンスカヤ

http://ja.wikipedia.org/wiki/%E3%82%A2%E3%83%A9%E3%83%BB%E3%83%A4%E3%83%AD%E3%82%B7%E3%83%B3%E3%82%B9%E3%82%AB%E3%83%A4

アラ・ヤロシンスカヤ （ウクライナ語: Ярошинська Алла Олександрівна、1953年2月14日-）は、ウクライナのジャーナリスト、政治家。

ウクライナ西部のジトームィルに生まれた。キエフ大学卒業後、13年間地方紙の記者。1986年のチェルノブイリ原子力発電所事故ののち、情報統制の枠を破って取材を重ね、ソビエト連邦政府の事故対応の問題点を糾弾し続けた。

1989年、ソビエト連邦人民代議員大会の議員に当選。地域間代議員グループに所属して事故の真相と責任を追及、被害者救済のために活動した。

1991年のソ連崩壊後に公表された秘密文書を入手し、1992年に«Чернобыль. Совершенно секретно»（『チェルノブイリ極秘―隠された事故報告』和田あき子訳、平凡社、1994年4月）を出版、住民の苦難の実相とこれをもたらした背景、政府の意思決定の秘密、政治家・学者の無責任さを明らかにした。^[1]

イズベスチア、コムソモリスカヤ・プラウダ、ノーヴァヤ・ガゼータ、ニューズウィーク、ニューヨークタイムズなどに記事を書いているほか、著書・論文多数。
1992年10月28日、日本記者クラブで会見に応じた^[2]。

最終更新 2013年3月19日 (火)

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Nuclear lies of Chernobyl



公開日: 2014/02/07

Nuclear industry lies about Chernobyl
0:00 - song info about Chernobyl
2:43 - Dr. Alexey Yablokov interview about his book he co-authored http://www.scribd.com/doc/126681397/Y...
3:21 - Deputy of the Supreme Soviet Union Alla Yaroshinskaya discovers a huge government cover up of Chernobyl to save the nuclear industry.
4:57 - Youri Bandazhevsky goes to jail for corruption because he exposes the dangers of chernobyl contamination.

Some history for you about Chernobyl which tells us the nuclear industry controls the government. This is important to note as it explains how the genocide of japan is happening right now from Fukushima. Chernobyl was mass cover up and the same thing is happening now with Fukushima, except Fukushima is a million times worse for humanity then chernobyl was.

On Facebook
https://www.facebook.com/photo.php?v=...

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THE TRUTH ABOUT  CHERINOBYL

http://books.google.com.au/books?hl=en&id=VtmW082nSaIC&dq=%22truth+about+chernobyl&printsec=frontcover&source=web&ots=5_mZTcolaP&sig=OrxJNPprZdtigX9a9bvNAbPaV40&sa=X&oi=book_result&resnum=4&ct=result#v=onepage&q=%22truth%20about%20chernobyl&f=false

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Trinity Atomic Web Site

Nuclear Weapons: History, Technology, and Consequences in Historic Documents, Photos, and Videos

http://www.cddc.vt.edu/host/atomic/accident/critical.html

CRITICALITY ACCIDENTS

(from Operational Accidents and Radiation Exposure Experience Within the United States Atomic Energy Commission, 1943-1970, U.S. Government Printing Office: Washington, D.C., 1971.)
In the AEC's operational activities (not licensed) for the past 28 years there have been a total of 26 occasions (see Chart XV) when the power level of fissile systems became uncontrollable because of unplanned or unexpected changes in the system reactivity. On three occasions, the power excursions were planned; however, the fission energy released during the excursion was significantly larger than was expected. There have been a total of six deaths attributable to criticality accidents. The property damage resulting from these excursions has been approximately $4,455,000; however, 98% of the property loss was due to the SL-1 reactor excursion.

Further study of this accident record reveals that nine of the unplanned excursions occurred behind heavy shielding and three of them occurred in facilities remotely located with respect to personnel. Hence, the probability of injuries to people was reduced almost to the vanishing point. It is also noted that fourteen of the accidents occurred during experiments, six occurred in production or processing facilities, and five in reactor activities. In these laboratory, production, and reactor facilities there were, respectively, two, one, and three fatalities.

A review of these incidents has been made by W. R. Stratton, University of California, Los Alamos Scientific Laboratory, Los Alamos, N. Mex. All we have done below is to prepare a brief description of each incident.

CRITICALITY EXCURSION INCIDENT

Oak Ridge, Tenn., Jan. 30, 1968

Unexpected criticality was achieved in a volume of an aqueous solution of a salt of U²³⁵ during a series of routine critical experiments in progress in a well-shielded assembly area of a critical experiments facility. The criticality radiation alarm system functioned as designed, the evacuation of personnel from the building was prompt and orderly, and the excursion was terminated expeditiously by a negative coefficient of reactivity and was prevented from recurring by the action of the safety devices. The fission yield was 1.1 X 10¹⁶. Gamma-ray sensitive personnel dosimeters read immediately following the excursion showed no direct exposure greater than 5 mr to any person present. There was no property damage or loss of fissile materials. An estimated 100 cm, of solution (15 g of U) were spilled when a rubber-stoppered connection immediately above the sphere was dislocated.

The purpose of the particular experiment in progress was to establish the critical concentration of a sphere of the solution of uranyl nitrate surrounded by a thick water reflector. In the course of approaching criticality by incremental additions of solution, a small volume of air was observed entrapped in a flexible transparent tube. Supercriticality occurred during an attempt, by remote manipulation of liquid levels, to remove the air.

ACCIDENTAL CRITICALITY EXCURSION

Los Alamos, N. Mex., May 18, 1967

A nuclear excursion of 4 x 10¹⁶ fissions took place in the critical mockup of a high power density reactor. There was neither damage to the equipment nor significant exposure of persons; nevertheless, the incident indicated poor practice and an undesirable interpretation of operating procedures which has been corrected. The reactor mockup is fueled with elements composed of fully enriched uranium in a graphite matrix, and a smaller number of graphite moderating elements. This permits a relatively small core volume (250 liters). The core, housed in a graphite cylinder, drops out of its Be reflector for loading. Control and safety drums are within the annular reflector.

Before the incident, fuel along the core axis was replaced by additional moderating elements to investigate flux-trap effects. Instead of the usual step-wise interchange of elements, the entire moderating island was installed. Then, instead of stepwise multiplication measurements while inserting the core into the reflector, which is proper for initial approaches to criticality, there were no measurements during interrupted insertion. It had been inferred from the behavior of different moderating elements in an earlier mockup that the overall reactivity change would be minor. This was a serious mistake, for the actual change proved to be about $10. Before complete closure was achieved, a very short period and scram (dropping the core and actuating the safety drums) occurred.

NUCLEAR EXCURSION AND FIRE

Livermore, Calif., Mar. 26, 1963

A nuclear excursion and subsequent fire took place during a subcritical experiment in a shielded vault designed for critical assembly experiments. The excursion was estimated at 4 X 10¹⁷ fissions and was followed by oxidation of the enriched uranium metal in the assembly.

The cause of the excursion is believed to have been directly attributable to mechanical failure.
The total property loss was $94,881.

NUCLEAR EXCURSION

Richland, Wash., Apr. 7, 1962

An unplanned nuclear excursion occurred in a plutonium processing facility because of the inadvertent accumulation of approximately 1500 grams of plutonium in 45-50 liters of dilute nitric acid solution in a 69-liter glass transfer tank. The sequence of events which led to the accumulation of the plutonium the tank cannot be stated positively. However, it is believed that, when a tank valve was opened, the solution from another process vessel overflowed to a sump and was drawn into the transfer tank through a temporary line between this tank and the sump.

When the excursion occurred, radiation and evacuation alarms sounded. All but three employees left the building immediately, according to well-prepared and -rehearsed evacuation plans. Fortunately, they were not in close proximity to the involved system nor in a high radiation field.

The course of the nuclear reaction involved initial criticality (10¹⁶ fissions); a subsidence; one or more later peaks; and after approximately one-half hour, a declining rate of fission, which terminated in a subcritical condition 37 hours later. The total number of fissions was approximately 8 X 10¹⁷.
Of the 22 persons in the building at the time, only four employees, those who were in the room with the system, were hospitalized for observation. Three of them were the system operators, who were in close proximity to the excursion, and who received estimated radiation doses of 110, 43 and 19 rem. None of them showed symptoms definitely referable to their radiation exposures. The fourth was sent to the hospital only because he was in the room at the time of the incident.

Some fission product activity, airborne via the vent system and the exhaust stack, was detected in the atmosphere for a brief period after the accident. The physical damage amounted to less than $1,000. (See TID-5360, Suppl. 4, page 17.)

NUCLEAR EXCURSION

Oak Ridge, Tenn., Nov. 10, 1961

A criticality excursion occurred as enriched uranium metal, neutron-reflected and -moderated by hydrogen, was being assembled. The excursion was caused by a too rapid approach of the two pieces of metal used in the experiment.

There was no personnel exposure or property damage. The energy release was estimated to be between 10¹⁵ and 10¹⁶ fissions. Fission product contamination, both airborne and contained in the metal, decayed sufficiently overnight to allow unhindered continuation of the experiment.

The incident occurred in a critical experiment laboratory specifically designed to accommodate such occurrences, since events of this nature cannot be considered entirely unexpected in an experimental facility of this sort. (See TID-5360. Suppl. 4, p. 14.)

CRITICALITY ACCIDENT

Idaho Falls, Idaho, Jan. 25, 1961

A nuclear excursion of approximately 6 X 10¹⁷ fissions occurred in a first-cycle product evaporator at a chemical processing plant. The criticality accident resulted when a solution of enriched uranyl nitrate accidentally surged from a geometrically safe section of the evaporator into the upper critically unsafe, vapor disengagement section. The accident occurred behind thick concrete walls in a processing cell which is part of the first cycle for processing highly radioactive spent-fuel elements.
Personnel response to the radiation alarms and the evacuation signal was prompt and orderly.

Analyses of badges from 65 individuals indicated a maximum exposure of 55 millirem gamma and 0 beta. The maximum thermal neutron exposure detected in the badges analyzed was less than 10 millirem. Analyses of nuclear accident dosimeters indicated that there was negligible fast neutron flux associated with personnel exposures.

The radioactivity released to the atmosphere as a result of the accident was about twice normal background when it left the area. Loss of $6,000 resulted from cleanup of the, incident. (See TID-5360, Suppl. 4, p. 9; 1961 Nuclear Safety, Vol. 3, #2, p. 71.)

SL-1 EXCURSION

Idaho Falls, Idaho, Jan. 3, 1961

A nuclear excursion occurred within the reactor vessel, resulting in extensive damage of the reactor core and room, and in high radiation levels (approximately 500-1,000 rem/hr) within the reactor room.

At the time of the accident, a three-man crew was on the top of the reactor assembling the control rod drive mechanisms and housing. The nuclear excursion, which resulted in an explosion, was caused by manual withdrawal, by one or more, of the maintenance crew, of the central control rod blade from the core considerably beyond the limit specified in the maintenance procedures.

Two members of the crew were killed instantly by the force of the explosion, and the third man died within two hours following the incident as a result of an injury to the head. Of the several hundred people engaged in recovery operations, 22 persons received radiation exposures in the range of three to 27 rem gamma radiation total-body exposure. The maximum whole-body beta radiation was 120 rem.

Some gaseous fission products, including radioactive iodine, escaped to the atmosphere outside the building and were carried downwind in a narrow plume. Particulate fission material was largely confined to the reactor building, with slight radioactivity in the immediate vicinity of the building.
The total property loss was $4,350,000. (See TlD-5360, Suppl. 4, p. 8; 1962 Nuclear Safety. Vol. 3, #3, p. 64.)

CRITICALITY INCIDENT

Idaho Falls, Idaho, Oct. 16, 1959

A nuclear incident occurred in a process equipment waste collection tank when an accidental transfer was made of about 200 liters of uranyl nitrate solution, containing about 34 kilograms of enriched uranium (91 percent U²³⁵), from safe process storage tanks to a geometrically unsafe tank through a line formerly used for waste transfers.

Limited visual inspections and test that no significant, property damage or loss resulted beyond the approximately $60,000 cost to recover contaminated uranium solution resulting from the incident.
Of the 21 personnel directly involved in this incident, seven received external exposures to radiation. The exposures were 8, 6, 3.95, 1.50, 1.38, 1.17, and 1.17 rem. Two individuals also received external exposures to the skin of 50 rem and 32 rem. No medical treatment was required for the 21 personnel involved. (See TID-5360, Suppl. 3, p. 14; USAEC Serious Accidents Issue #163, 4-18-60.)

FATAL INJURY ACCOMPANIES CRITICALITY ACCIDENT

Los Alamos, N. Mex., Dec. 30, 1958

The chemical operator introduced what was believed to be a dilute plutonium solution from one tank into another known to contain more plutonium in emulsion. Solids containing plutonium were probably washed from the bottom of the first tank with nitric acid and the resultant mixture of nitric acid and plutonium-bearing solids was added to the tank containing the emulsion. A criticality excursion occurred immediately after starting the motor to a propeller type stirrer at the bottom of the second tank.

The operator fell from the low stepladder on which he was standing and stumbled out of the door into the snow. A second chemical operator in an adjoining room had seen a flash, which probably resulted from a short circuit when the motor to the stirrer started, and went to the man's assistance. The accident victim mumbled he felt as though he was burning up. Because of this, it was assumed that there had been a chemical accident with a probable acid or plutonium exposure. There was no realization that a criticality accident had occurred for a number of minutes. The quantity of plutonium which actually was present in the tank was about ten times more than was supposed to be there at any time during the procedure.

The employee died 35 hours later from the effects of a radiation exposure with the whole-body dose calculated to be 12,000 rem +.
Two other employees received radiation exposures of 134 and 53 rem, respectively. Property damage was negligible. (See TID-5360, Suppl 2, p. 30; USAEC Serious Accidents Issue #143, 1-22-59.)

NUCLEAR EXCURSION

Oak Ridge, Tenn., June 16, 1958

A nuclear accident occurred in a 55-gallon stainless steel drum in a processing area in which enriched uranium is recovered from various materials by chemical methods in a complex of equipment. This recovery process was being remodeled at the time of the accident.
The incident occurred while they were draining material thought to be water from safe 5-inch storage pipes into an unsafe drum.

Eight employees were in the vicinity of the drum carrying out routine plant operations and maintenance. A chemical operator was participating in the leak testing which inadvertently set off the reaction. He was within three to six feet of the drum, while the other seven employees were from 15 to 50 feet away.

Using special post hoc methods for determining the neutron and gamma exposures of the employees involved, it was estimated that the eight men received: 461 rem, 428 rem, 413 rem, 341 rem, 298 rem, 86 rem, 86 rem, and 29 rem.

Area contamination was slight, with decontamination costs amounting to less than $1,000.

During this incident 1.3 X 10¹⁸ fissions occurred. (See TID-5360, Suppl. 2, p. 25; USAEC Serious Accidents Issue #136, 8-25-59; USAEC Health and Safety Information Issue # 82, 9-5-58; 1959 Nuclear Safety, Vol. 1, #2, p. 59.)

GODIVA EXCURSION

Los Alamos, N. Mex., Feb. 12, 1957

The "Godiva" assembly was to be used to irradiate uranium-loaded graphite samples. The samples were to be heated in a shielded furnace, exposed to a "prompt" burst of neutrons and then transferred to a counter for evaluation. The experiments are conducted at an isolated site in a building separated from the control room and all personnel by about a quarter of a mile.

On the occasion of the accident, preliminary bursts were being produced. In the process of lowering the top safety block, an unexpected burst occurred that was estimated to have produced 1.2 X 10¹⁷ fissions. The energy was great enough to tear the uranium parts from the assembly, knocking one to the floor, and to distort the steel rods in the frame. The uranium was deformed and there was much more surface oxidation than usual.

There were no personal injuries or overexposures. No gamma radiation above background was detected outside the reactor building. Radiation levels in the building were high initially . . . seven roentgens per hour gamma just inside the door (12' from Godiva) and 5,000 to 20,000 counts per minute (per 55 cm² probe) alpha on horizontal surfaces about the room; therefore cleanup procedures were delayed 2-1/2 days until they could be completed without unnecessary exposure to cleanup personnel.

The total property loss was estimated at $2,400.
(See TID-5360, Suppl. 2, p. 18; USAEC Health and Safety Information Issue #75, 1-8-58.)

HONEYCOMB EXCURSION

Los Alamos, N. Mex., July 3, 1956

Too rapid assembly caused the system to become promptly critical. The burst yield was 3.2 X 10¹⁶ fissions.
There were no radiation exposures nor any property damage as a result of the incident.

EXPERIMENTAL REACTOR

Oak Ridge, Tenn., Feb. 1, 1956

A homogenous UO₂F₂, water-moderated critical assembly was made prompt critical by an overaddition of fuel to the assembly. Before reaching the critical point, the hand-operated valve was turned off. However, fuel continued to be added to the reactor because of air pressure in the line. Although the automatic safety system operated, assuring termination of the burst, considerable fuel was displaced from the reactor. The number of fissions in the burst was estimated to be about 1.6 X 10¹⁷.

No serious exposures resulted, since all personnel were shielded by a minimum of five feet of concrete. There was no significant property damage and all uranium was recovered. (See TID-5360, Suppl. 1, p. 5.)

CORE MELTDOWN

Idaho Falls, Idaho, Nov. 29, 1955

The Experimental Breeder Reactor (EBR-I) was undergoing a series of experiments.
Without modification, certain safety instrumentation. would not permit the conduct of the experiment; therefore, reliance was placed on manual control to shut down the reactor.

During an experiment, the scientist in charge told the operator to press the "emergency reactor off" button. This would have instantaneously removed sufficient reactivity. Owing to a misunderstanding, the operator began by withdrawing the control rods at normal speed. This allowed the reactor to reach a higher power than anticipated and resulted in consequent melting of the fuel elements.
Shortly after the accident, there was a rise in the radiation level in the building. The building was evacuated. There were no personnel injuries. There was minor contamination of the sodium potassium coolant. (See TID-5360, p. 30.)

BORAX 1 EXPLOSION

Idaho Falls, Idaho, July 22, 1954

Destruction of the Borax I Reactor released 135 MW-sec of fission energy.
More than 200 safety experiments were made on the Borax I Reactor simulating control rod accidents. For the last test, conditions were set up so that the reactor would be run to destruction.

The tests were carried out by withdrawing four of the five control rods far enough to make the reactor critical at a very low power level. The fifth rod was then fired from the core by means of a spring. In this test, the rod was ejected in approximately 0.2 seconds. After the control rod was ejected, an explosion took place in the reactor which carried away the control mechanism and blew out the core. At half a mile, the radiation level rose to 25 mr/hr. Personnel were evacuated for about 30 minutes.
No one was injured and the destruction of the reactor was part of the cost of the experiment. (See TID-5360, p. 29.)

EXCURSION IN AN ENRICHED URANIUM WATER SOLUTION

Oak Ridge, Tenn., May 26, 1954

The experiment in progress at the time of the incident was one in a series designed to study criticality conditions of uranium-water solutions in annular cylindrical containers.

The cause of the accident was a. displacement of the central tube, effectively a poison rod, to a region of less importance. This displacement resulted from a dislocation of the positioning spider by a pin, used to connect sections of the liquid level indicator rack, protruding beyond the side of the rack and engaging a leg of the spider as the indicator was raised. Removing the compressional force from the top of the central tube allowed it to fall against the inside of the 10-inch cylinder. Although the displacement was small, it was sufficient to cause a large increase in the effective neutron multiplication.

The safety system apparently operated normally and the reaction was stopped automatically. All personnel in the building during the incident, were protected by a minimum of five feet of concrete shielding; therefore, no serious exposures were incurred. (See TID-5360, p. 18.)

SUPERCRITICALITY EXPERIMENT

Los Alamos, N. Mex., Feb. 3, 1954

The incident occurred in the course of an extensive study of the properties of supercritical radiation bursts produced by an assembly of fissionable metal. This study was covered by a specific procedure. A reference check of critical conditions preceded each supercritical burst.

To attain rapidly sufficient power for a delayed critical check, it was customary to set control rods at the position of minimum reactivity and insert a reactivity booster in the form of a fissionable metal slug. This time, when the booster was inserted, radiation indicators and the assembly temperature recorded went offscale (to return in a few minutes), and scrams were actuated. The resulting shock separated parts of the assembly and damaged steel supporting members.

There was no injury. The property loss was an expenditure of $600 for repair of the assembly. (See TID-5360, p. 9.)

SUDDEN INCREASE IN REACTIVITY DURING CONTROL ROD TESTS

Lemont, Ill., June 2, 1952

Manual withdrawal of a control rod from a. critical assembly caused an accidental supercriticality.
The operation being conducted was the comparison of a series of newly-manufactured control rods. The assembly had been operated with the standard control rod. It was then shut down by inserting all control rods and draining the water moderator, a, standard safe method of shutting down the assembly when core changes are to be made. The standard rod was removed and the first of the series of control rods to be tested was inserted.

The assembly was filled with water with the test control rod fully in and the standard type control rods fully inserted. Withdrawal of one of the standard control rods 32 centimeters caused the assembly to become critical and the power was leveled off while the desired measurements were made. The control rod was then reinserted into the original "in" position.

With the water still in the assembly, the four members of the crew then went into the assembly room for the purpose of replacing the control rod which they had just tested. The group leader went up on the platform, reached out with his right hand and started to pull out the tested rod. As soon as he had withdrawn it about one foot, the center of the assembly emitted a bluish glow and a large bubble formed. Simultaneously, there was a muffled explosive noise. The group leader let go of the control rod which he was removing and it fell back into position. The crew left the assembly room immediately and went to the control room.

Four employees received radiation exposures ranging from 12 to 190 rem. (See TID-5360, p. 23.)

CRITICALITY RESULTS FROM ERROR IN CALCULATIONS

Los Alamos, N. Mex., Apr. 18, 1952

Two stacks of fissionable disks were being built up stepwise to give a slightly subcritical assembly with the two stacks brought together by remote control. The individual stacks were built up by hand in fixed assemblies and the two stacks brought together only by remote mechanisms.
After two members of the operating crew calculated erroneously from previous steps that one more disk could be added safely, the disk was added and, with attempted caution, the system was assembled remotely. Radiation indicators went offscale, actuating scrams, neutron counters jammed, and a puff of smoke was observed on the television viewer. Within three to five minutes indicators and counters returned to operating ranges.
There was no injury, no loss of material, no damage to facilities, and negligible loss of operating time. (See TID-5360, p. 7.)

EXCURSION IN A PLUTONIUM NITRATE SOLUTION

Richland, Wash., Nov. 16, 1951

Upon completion of volume measurements, it was thought that some additional information as to the required dilution could be determined by finding where criticality might occur on the rods. The control rod was pulled first with very minor reactivity effect. Following this, the safety rod was withdrawn intermittently at high speed (2.3"/sec). A waiting period for the delayed neutron effect of about 15 seconds was made just prior to the incident. This was too short a time to determine whether or not the assembly was critical. The operators next heard the safety controls actuate, instrument indicators moved offscale, scalers jammed, and the most startling manifestation was that of the breakdown of "counters" playing back through the public address system. The portable "Juno" in the control room was offscale. Presumably, a further rod withdrawal had been made.

There were no injuries. The building was successfully decontaminated, except for the test room and assembly. Before decontamination of this area was completed, a fire occurred and, subsequently, the building was abandoned because of the respread of contamination. (See TID-5360, p. 14.)

SCRAM MECHANISM CAUSES CRITICALITY

Los Alamos, N. Mex., Mar. 20, 1951

Interactions between two masses of fissionable material in water were measured at progressively decreasing horizontal separations. Remotely controlled operations established the desired horizontal separation of the two components and flooded the system.

After the final measurement, the system was "scrammed" (a rapid disassembly mechanism was actuated). Safety monitor indicators went offscale, neutron counters jammed, and the television viewer indicated steaming. Within a few minutes, indicators and counters returned to operating ranges and indicated a rapid decay of radiation.

There was no injury, no loss of material, and no damage to facilities. (See TlD-5360, p. 13.)

CRITICALITY DURING CONTROL ROD TESTS

Los Alamos, N. Mex., December 1949

The reactor was being remodeled for higher power operation. As part of the required alterations, two new control rods had been placed in the system in addition to the three existing control rods.
The employee who had built the rod control mechanism wanted to test the comparative fall times of these new rods. He opened the enclosure on top of the reactor and manually lifted the rods, neglecting the possibility that this would affect the reactivity of the reactor because of its higher power arrangement. Heretofore, the three existing rods were sufficient for safety.

Normally, rods are raised remotely from the control room when the control panel is activated by a key switch. Since the rods were pulled out manually with the panel being off, no equipment was turned on except a direct reading temperature meter. Therefore, there were no neutron sensitive devices to record or warn of a rise in the neutron level. It was not observed until after the incident that the reactor temperature had risen about 25 centigrade.

The removal of the two rods probably gave a delta-K of about 0.86 percent, producing an initial period of about 0.16 second. Since the measured temperature coefficient is approximately 0.034 percent k/C, the observed temperature rise indicates the rods were out sufficiently long so that the reactor was stopped by the negative temperature coefficient.

There were no injuries. The employee doing the work received 2.5 rem of gamma radiation according to his film badge. There was no damage done to the reactor and no loss of active material. (See TID-5360, p. 21.)

INADVERTENT SUPERCRITICALITY RESULTS IN DEATH

Los Alamos, N. Mex., May 21, 1946

A senior scientist [Louis Slotin] was demonstrating the technique of critical assembly and associated studies and measurements to another scientist. The particular technique employed in the demonstration was to bring a hollow hemisphere of beryllium around a mass of fissionable material which was resting in a similar lower hollow hemisphere.

The system was checked with two one-inch spacers between the upper hemisphere and the lower shell which contained the fissionable material; the system was subcritical at this time.

Then the spacers were removed so that one edge of the upper hemisphere rested on the lower shell while the other edge of the upper hemisphere was supported by a screwdriver. This latter edge was permitted to approach the lower shell slowly. While one hand held the screwdriver, the other hand was holding the upper shell with the thumb placed in an opening at the polar point.

At that time, the screwdriver apparently slipped and the upper shell fell into position around the fissionable material. Of the eight people in the room, two were directly engaged in the work leading to this incident.

The "blue glow" was observed, a heat wave felt, and immediately the top shell was slipped off and everyone left the room. The scientist who was demonstrating the experiment received sufficient dosage to result in injuries from which he died nine days later. The scientist assisting received sufficient radiation dosage to cause serious injuries and some permanent partial disability.

The other six employees in the room suffered no permanent injury. (See TID-5360, p. 4.)

FATALITY FROM CRITICAL MASS EXPERIMENTS

Los Alamos, N. Mex., Aug. 21, 1945

During the process of making critical mass studies and measurements, an employee [Harry Daghlian] working in the laboratory at night alone (except for a guard seated 12 feet away) was stacking blocks of tamper material around a mass of fissionable material.

As the assembly neared a, critical configuration, the employee was lifting one last piece of tamper material which was quite heavy. As this piece neared the setup, the instrument indicated that fission multiplication would be produced, and as the employee moved his hand to set the block at a distance from the pile, he dropped the block, which landed directly on top of the setup.

A "blue glow" was observed and the employee proceeded to disassemble the critical material and its tamper. In doing so, he added heavily to the radiation dosage to his hands and arms.

The employee received sufficient radiation dosage to result in injuries from which he died 28 days later.

The guard suffered no permanent injury. (See TID-5360, p. 2.)

UNANTICIPATED CRITICALITY IN WATER-SHIELDED ASSEMBLY

Los Alamos, N. Mex., June 4, 1945

An experiment was designed to measure the critical mass of enriched uranium when surrounded by hydrogenous material. The enriched uranium was in the form of cast blocks of the metal, 1/2" X 1/2" X 1/2" and 1/2" X 1/2" X 1". The blocks were stacked in a pseudospherical arrangement in 12 courses in a 6" X 6" X 6" polyethylene box. The voids in the courses were filled with polyethylene blocks of appropriate dimensions. The polyethylene box was supported by a 2-foot-high stool within a 3-foot cubical steel tank. The tank had a 2-inch opening in the bottom through which it could be filled and drained by means of supply and drain hoses attached to a 3/4-inch tee. The opening in the tank was fitted with a shutoff valve, as was the drain hose. A polonium-beryllium source of about 200 mc strength was placed on top of the assembly. A fission chamber and a boron proportional counter were used to follow the experiment.

The immediate supervisor was absent from the scene when the experiment was begun. According to one of the operators, the water level was raised above the polonium-beryllium source with the supply valve almost fully open. At this point, a slight increase counting rate was observed, which corresponded with what had been observed previously when the source alone was immersed in water.

A few seconds later, the counting rate began to increase at an alarming rate.

At this point, the supervisor returned, walked to within three feet of the tank and noted a blue glow surrounding the box. Simultaneously, the two operators were hastily closing the supply valve and opening the drain valve. The building was evacuated.

The three individuals involved received excessive radiation exposures, estimated in two cases as about 66.5 rem, and in the third as 7.4 rem. The doses delivered to the head and neck of these individuals may have been considerably greater. They were hospitalized for observation, but no untoward symptoms appeared. No significant changes in blood counts were observed, and sperm counts on one occasion, sometime after the incident, were normal. It is not believed that the individuals concerned received any significant radiation damage. There was no damage to equipment, no loss of active material, and no local contamination problem. (See TID-5360, p. 10.)

DRAGON REACTOR EXCURSION

Los Alamos, N. Mex., Feb. 11, 1945

This was the first reactor designed to generate prompt power excursions. Prompt critical was obtained by dropping a slug of UH₃ in styrex through a vertical hole in a small assembly of the same material, which was diluted with polyethylene and reflected by graphite and polyethylene. Near the end of the planned sequence of burst of increasing power, a 6 X 10¹⁵ fission burst blistered and swelled the small cubes comprising the assembly matrix. No material was lost, there was no contamination, and there were no exposures.

Contents

●　Trinity Atomic Test Site
●　Hiroshima and Nagasaki
●　Nuclear Weapon Physics and Technology
●　Effects of Nuclear Weapons and Nuclear War
●　The Years of Atmospheric Testing
●　Gallery of Test Photos
●　Civil Defense
●　Criticality and Radiation Accidents
●　Los Alamos Publications (no longer) Online
●　Other Online Sources
●　Annotated Bibliography

Related Links

●　Alsos Digital Library for Nuclear Issues: Nuclear Accidents
●　atomicarchive.com: Nuclear Weapons Accidents Interactive Map

---

Copyright © 1995-2005 Gregory Walker (trinatomic at earthlink dot net), Creator of Trinity Atomic Web Site.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1, or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

===============================================================

A Review of
Criticality Accidents
2000 Revision

http://www.orau.org/ptp/Library/accidents/la-13638.pdf

ＰＤＦ:１５８ｐ

Los Alamos
N A T I O N A L　 L A B O R A T O R Y
Los Alamos, New Mexico 87545

Los Alamos National Laboratory is operated by the University of California for the United States Department of Energy
under contract W-7405-ENG-36.

===============================================================

THE ATOMIC BOMBINGS OF HIROSHIMA AND NAGASAKI

http://www.cddc.vt.edu/host/atomic/hiroshim/hiro_med.html

THE ATOMIC BOMBINGS OF HIROSHIMA AND NAGASAKI

by The Manhattan Engineer District, June 29, 1946.

Index

• FOREWORD
• INTRODUCTION
• THE MANHATTAN PROJECT INVESTIGATING GROUP
• PROPAGANDA
• SUMMARY OF DAMAGES AND INJURIES
• MAIN CONCLUSIONS
• THE SELECTION OF THE TARGET
• DESCRIPTION OF THE CITIES BEFORE THE BOMBINGS

Hiroshima
Nagasaki

THE ATTACKS

Hiroshima
Nagasaki

• GENERAL COMPARISON OF HIROSHIMA AND NAGASAKI
• GENERAL DESCRIPTION OF DAMAGE CAUSED BY THE ATOMIC EXPLOSIONS
• TOTAL CASUALTIES
• THE NATURE OF AN ATOMIC EXPLOSION
• CHARACTERISTICS OF THE DAMAGE CAUSED BY THE ATOMIC BOMBS
• CALCULATIONS OF THE PEAK PRESSURE OF THE BLAST WAVE
• LONG RANGE BLAST DAMAGE
• GROUND SHOCK
• SHIELDING, OR SCREENING, FROM THE BLAST
• FLASH BURN
• CHARACTERISTICS OF INJURIES TO PERSONS
• BURNS
• MECHANICAL INJURIES
• BLAST INJURIES
• RADIATION INJURIES
• SHIELDING FROM RADIATION
• EFFECTS OF THE ATOMIC BOMBINGS ON THE INHABITANTS OF THE CITIES

APPENDIX: Father Siemes' eyewitness account
Figure 1: Probable position of rising cloud at intervals after explosion

FOREWORD

This report describes the effects of the atomic bombs which were dropped on the Japanese cities of Hiroshima and Nagasaki on August 6 and 9, 1945, respectively. It summarizes all the authentic information that is available on damage to structures, injuries to personnel, morale effect, etc., which can be released at this time without prejudicing the security of the United States.

This report has been compiled by the Manhattan Engineer District of the United States Army under the direction of Major General Leslie R. Groves. Special acknowledgement to those whose work contributed largely to this report is made to:

The Special Manhattan Engineer District Investigating Group,

The United States Strategic Bombing Survey,

The British Mission to Japan, and

The Joint Atomic Bomb Investigating Group (Medical). and particularly to the following individuals:

Col. Stafford L. Warren, Medical Corps, United States Army, for his evaluation of medical data,
Capt. Henry L. Barnett, Medical Corps, United States Army, for his evaluation of medical data,
Dr. R. Serber, for his comments on flash burn,
Dr. Hans Bethe, Cornell University, for his information of the nature of atomic explosions,

Majors Noland Varley and Walter C. Youngs, Corps of Engineers, United States Army, for their evaluation of physical damage to structures,

J. 0. Hirschfelder, J. L. Magee, M. Hull, and S. T. Cohen, of the Los Alamos Laboratory, for their data on nuclear explosions,

Lieut. Col. David B. Parker, Corps of Engineers, United States Army, for editing this report.

INTRODUCTION

Statement by the President of the United States: "Sixteen hours ago an American airplane dropped one bomb on Hiroshima, Japan, and destroyed its usefulness to the enemy. That bomb had more power than 20,000 tons of T.N.T. It had more than two thousand times the blast power of the British Grand Slam, which is the largest bomb ever yet used in the history of warfare".

These fateful words of the President on August 6th, 1945, marked the first public announcement of the greatest scientific achievement in history. The atomic bomb, first tested in New Mexico on July 16, 1945, had just been used against a military target.

On August 6th, 1945, at 8:15 A.M., Japanese time, a B-29 heavy bomber flying at high altitude dropped the first atomic bomb on Hiroshima. More than 4 square miles of the city were instantly and completely devastated. 66,000 people were killed, and 69,000 injured.

On August 9th, three days later, at 11:02 A.M., another B-29 dropped the second bomb on the industrial section of the city of Nagasaki, totally destroying 1 1/2 square miles of the city, killing 39,000 persons, and injuring 25,000 more.

On August 10, the day after the atomic bombing of Nagasaki, the Japanese government requested that it be permitted to surrender under the terms of the Potsdam declaration of July 26th which it had previously ignored.

THE MANHATTAN PROJECT ATOMIC BOMB INVESTIGATING GROUP

On August 11th, 1945, two days after the bombing of Nagasaki, a message was dispatched from Major General Leslie R. Groves to Brigadier General Thomas F. Farrell, who was his deputy in atomic bomb work and was representing him in operations in the Pacific, directing him to organize a special Manhattan Project Atomic Bomb Investigating Group.

This Group was to secure scientific, technical and medical intelligence in the atomic bomb field from within Japan as soon as possible after the cessation of hostilities. The mission was to consist of three groups:

1. Group for Hiroshima.
2. Group for Nagasaki.
3. Group to secure information concerning general Japanese activities in the field of atomic bombs.

The first two groups were organized to accompany the first American troops into Hiroshima and Nagasaki.

The primary purposes of the mission were as follows, in order of importance:

1. To make certain that no unusual hazards were present in the bombed cities.
2. To secure all possible information concerning the effects of the bombs, both usual and unusual, and particularly with regard to radioactive effects, if any, on the targets or elsewhere.

General Groves further stated that all available specialist personnel and instruments would be sent from the United States, and that the Supreme Allied Commander in the Pacific would be informed about the organization of the mission.

On the same day, 11 August, the special personnel who formed the part of the investigating group to be sent from the United States were selected and ordered to California with instructions to proceed overseas at once to accomplish the purposes set forth in the message to General Farrell. The main party departed from Hamilton Field, California on the morning of 13 August and arrived in the Marianas on 15 August.

On 12 August the Chief of Staff sent the Theater Commander the following message:
"FOR MACARTHUR, SIGNED MARSHALL:
"GROVES HAS ORDERED FARRELL AT TINIAN TO ORGANIZE A SCIENTIFIC GROUP OF THREE SECTIONS FOR POTENTIAL USE IN JAPAN IF SUCH USE SHOULD BE DESIRED.
THE FIRST GROUP IS FOR HIROSHIMA, THE SECOND FOR NAGASAKI, AND THE THIRD FOR THE PURPOSE OF SECURING INFORMATION CONCERNING GENERAL JAPANESE ACTIVITIES IN THE FIELD OF ATOMIC WEAPONS. THE GROUPS FOR HIROSHIMA AND NAGASAKI SHOULD ENTER THOSE CITIES WITH THE FIRST AMERICAN TROOPS IN ORDER THAT THESE TROOPS SHALL NOT BE SUBJECTED TO ANY POSSIBLE TOXIC EFFECTS ALTHOUGH WE HAVE NO REASON TO BELIEVE THAT ANY SUCH EFFECTS ACTUALLY EXIST. FARRELL AND HIS ORGANIZATION HAVE ALL AVAILABLE INFORMATION ON THIS SUBJECT."

General Farrell arrived in Yokohama on 30 August, with the Commanding General of the 8th Army; Colonel Warren, who was Chief of the Radiological Division of the District, arrived on 7 September. The main body of the investigating group followed later. Preliminary inspections of Hiroshima and Nagasaki were made on 8-9 and 13-14 September, respectively. Members of the press had been enabled to precede General Farrell to Hiroshima.

The special groups spent 16 days in Nagasaki and 4 days in Hiroshima, during which time they collected as much information as was possible under their directives which called for a prompt report. After General Farrell returned to the U.S. to make his preliminary report, the groups were headed by Brigadier General J. B. Newman, Jr. More extensive surveys have been made since that time by other agencies who had more time and personnel available for the purpose, and much of their additional data has thrown further light on the effects of the bombings. This data has been duly considered in the making of this report.

PROPAGANDA

On the day after the Hiroshima strike, General Farrell received instructions from the War Department to engage in a propaganda campaign against the Japanese Empire in connection with the new weapon and its use against Hiroshima. The campaign was to include leaflets and any other propaganda considered appropriate. With the fullest cooperation from CINCPAC of the Navy and the United States Strategic Air Forces, he initiated promptly a campaign which included the preparation and distribution of leaflets, broadcasting via short wave every 15 minutes over radio Saipan and the printing at Saipan and distribution over the Empire of a Japanese language newspaper which included the description and photographs of the Hiroshima strike.

The campaign proposed:

1. Dropping 16,000,000 leaflets in a period of 9 days on 47 Japanese cities with population of over 100,000. These cities represented more than 40% of the total population.
2. Broadcast of propaganda at regular intervals over radio Saipan.
3. Distribution of 500,000 Japanese language newspapers containing stories and pictures of the atomic bomb attacks.

The campaign continued until the Japanese began their surrender negotiations. At that time some 6,000,000 leaflets and a large number of newspapers had been dropped. The radio broadcasts in Japanese had been carried out at regular 15 minute intervals.

SUMMARY OF DAMAGES AND INJURIES

Both the Hiroshima and the Nagasaki atomic bombs exhibited similar effects.

The damages to man-made structures and other inanimate objects was the result in both cities of the following effects of the explosions:

A. Blast, or pressure wave, similar to that of normal explosions.

B. Primary fires, i.e., those fires started instantaneously by the heat radiated from the atomic explosion.

C. Secondary fires, i.e., those fires resulting from the collapse of buildings, damage to electrical systems, overturning of stoves, and other primary effects of the blast.

D. Spread of the original fires (B and C) to other structures.

The casualties sustained by the inhabitants of both cities were due to:

A. "Flash" burns, caused directly by the almost instantaneous radiation of heat and light at the moment of the explosion.

B. Burns resulting from the fires caused by the explosion.

C. Mechanical injuries caused by collapse of buildings, flying debris, and forceable hurling - about of persons struck by the blast pressure waves.

D. Radiation injuries caused by the instantaneous penetrating radiation (in many respects similar to excessive X-ray exposure) from the nuclear explosion; all of these effective radiations occurred during the first minute after initiation of the explosion, and nearly all occurred during the first second of the explosion.

No casualties were suffered as a result of any persistent radioactivity of fission products of the bomb, or any induced radioactivity of objects near the explosion. The gamma radiations emitted by the nuclear explosion did not, of course, inflict any damage on structures.

The number of casualties which resulted from the pure blast effect alone (i.e., because of simple pressure) was probably negligible in comparison to that caused by other effects.

The central portions of the cities underneath the explosions suffered almost complete destruction. The only surviving objects were the frames of a small number of strong reinforced concrete buildings which were not collapsed by the blast; most of these buildings suffered extensive damage from interior fires, had their windows, doors, and partitions knocked out, and all other fixtures which were not integral parts of the reinforced concrete frames burned or blown away; the casualties in such buildings near the center of explosion were almost 100%. In Hiroshima fires sprang up simultaneously all over the wide flat central area of the city; these fires soon combined in an immense "fire storm" (high winds blowing inwards toward the center of a large conflagration) similar to those caused by ordinary mass incendiary raids; the resulting terrific conflagration burned out almost everything which had not already been destroyed by the blast in a roughly circular area of 4.4 square miles around the point directly under the explosion (this point will hereafter in this report be referred to as X). Similar fires broke out in Nagasaki, but no devastating fire storm resulted as in Hiroshima because of the irregular shape of the city.

In both cities the blast totally destroyed everything within a radius of 1 mile from the center of explosion, except for certain reinforced concrete frames as noted above. The atomic explosion almost completely destroyed Hiroshima's identity as a city. Over a fourth of the population was killed in one stroke and an additional fourth seriously injured, so that even if there had been no damage to structures and installations the normal city life would still have been completely shattered. Nearly everything was heavily damaged up to a radius of 3 miles from the blast, and beyond this distance damage, although comparatively light, extended for several more miles. Glass was broken up to 12 miles.

In Nagasaki, a smaller area of the city was actually destroyed than in Hiroshima, because the hills which enclosed the target area restricted the spread of the great blast; but careful examination of the effects of the explosion gave evidence of even greater blast effects than in Hiroshima. Total destruction spread over an area of about 3 square miles. Over a third of the 50,000 buildings in the target area of Nagasaki were destroyed or seriously damaged. The complete destruction of the huge steel works and the torpedo plant was especially impressive. The steel frames of all buildings within a mile of the explosion were pushed away, as by a giant hand, from the point of detonation. The badly burned area extended for 3 miles in length. The hillsides up to a radius of 8,000 feet were scorched, giving them an autumnal appearance.

MAIN CONCLUSIONS

The following are the main conclusions which were reached after thorough examination of the effects of the bombs dropped on Hiroshima and Nagasaki:

1. No harmful amounts of persistent radioactivity were present after the explosions as determined by:

A. Measurements of the intensity of radioactivity at the time of the investigation; and
B. Failure to find any clinical evidence of persons harmed by persistent radioactivity.

The effects of the atomic bombs on human beings were of three main types:

A. Burns, remarkable for (1) the great ground area over which they were inflicted and (2) the prevalence of "flash" burns caused by the instantaneous heat radiation.

B. Mechanical injuries, also remarkable for the wide area in which suffered.

C. Effects resulting from penetrating gamma radiation. The effects from radiation were due to instantaneous discharge of radiation at the moment of explosion and not to persistent radioactivity (of either fission products or other substances whose radioactivity might have been induced by proximity to the explosions).

The effects of the atomic bombs on structures and installations were of two types:

A. Destruction caused by the great pressure from the blast; and

B. Destruction caused by the fires, either started directly by the great heat radiation, or indirectly through the collapse of buildings, wiring, etc.

4. The actual tonnage of T.N.T. which would have caused the same blast damage was approximately of the order of 20,000 tons.

5. In respect to their height of burst, the bombs performed exactly according to design.

6. The bombs were placed in such positions that they could not have done more damage from any alternative bursting point in either city.

7. The heights of burst were correctly chosen having regard to the type of destruction it was desired to cause.

8. The information collected would enable a reasonably accurate prediction to be made of the blast damage likely to be caused in any city where an atomic explosion could be effected.

THE SELECTION OF THE TARGET

Some of the most frequent queries concerning the atomic bombs are those dealing with the selection of the targets and the decision as to when the bombs would be used.

The approximate date for the first use of the bomb was set in the fall of 1942 after the Army had taken over the direction of and responsibility for the atomic bomb project. At that time, under the scientific assumptions which turned out to be correct, the summer of 1945 was named as the most likely date when sufficient production would have been achieved to make it possible actually to construct and utilize an atomic bomb. It was essential before this time to develop the technique of constructing and detonating the bomb and to make an almost infinite number of scientific and engineering developments and tests. Between the fall of 1942 and June 1945, the estimated probabilities of success had risen from about 60% to above 90%; however, not until July 16, 1945, when the first full-scale test took place in New Mexico, was it conclusively proven that the theories, calculations, and engineering were correct and that the bomb would be successful.

The test in New Mexico was held 6 days after sufficient material had become available for the first bomb. The Hiroshima bomb was ready awaiting suitable weather on July 31st, and the Nagasaki bomb was used as soon after the Hiroshima bomb as it was practicable to operate the second mission.

The work on the actual selection of targets for the atomic bomb was begun in the spring of 1945. This was done in close cooperation with the Commanding General, Army Air Forces, and his Headquarters. A number of experts in various fields assisted in the study. These included mathematicians, theoretical physicists, experts on the blast effects of bombs, weather consultants, and various other specialists. Some of the important considerations were:

A. The range of the aircraft which would carry the bomb.

B. The desirability of visual bombing in order to insure the most effective use of the bomb.

C. Probable weather conditions in the target areas.

D. Importance of having one primary and two secondary targets for each mission, so that if weather conditions prohibited bombing the target there would be at least two alternates.

E. Selection of targets to produce the greatest military effect on the Japanese people and thereby most effectively shorten the war.

F. The morale effect upon the enemy.

These led in turn to the following:
A. Since the atomic bomb was expected to produce its greatest amount of damage by primary blast effect, and next greatest by fires, the targets should contain a large percentage of closely-built frame buildings and other construction that would be most susceptible to damage by blast and fire.

B. The maximum blast effect of the bomb was calculated to extend over an area of approximately 1 mile in radius; therefore the selected targets should contain a densely built-up area of at least this size.

C. The selected targets should have a high military strategic value.

D. The first target should be relatively untouched by previous bombing, in order that the effect of a single atomic bomb could be determined.
The weather records showed that for five years there had never been two successive good visual bombing days over Tokyo, indicating what might be expected over other targets in the home islands.

The worst month of the year for visual bombing was believed to be June, after which the weather should improve slightly during July and August and then become worse again during September. Since good bombing conditions would occur rarely, the most intense plans and preparations were necessary in order to secure accurate weather forecasts and to arrange for full utilization of whatever good weather might occur. It was also very desirable to start the raids before September.

DESCRIPTION OF THE CITIES BEFORE THE BOMBINGS

Hiroshima

The city of Hiroshima is located on the broad, flat delta of the Ota River, which has 7 channel outlets dividing the city into six islands which project into Hiroshima Bay. The city is almost entirely flat and only slightly above sea level; to the northwest and northeast of the city some hills rise to 700 feet.

A single hill in the eastern part of the city proper about 1/2 mile long and 221 feet in height interrupted to some extent the spreading of the blast damage; otherwise the city was fully exposed to the bomb. Of a city area of over 26 square miles, only 7 square miles were completely built-up. There was no marked separation of commercial, industrial, and residential zones. 75% of the population was concentrated in the densely built-up area in the center of the city.

Hiroshima was a city of considerable military importance. It contained the 2nd Army Headquarters, which commanded the defense of all of southern Japan. The city was a communications center, a storage point, and an assembly area for troops. To quote a Japanese report, "Probably more than a thousand times since the beginning of the war did the Hiroshima citizens see off with cries of 'Banzai' the troops leaving from the harbor."

The center of the city contained a number of reinforced concrete buildings as well as lighter structures. Outside the center, the area was congested by a dense collection of small wooden workshops set among Japanese houses; a few larger industrial plants lay near the outskirts of the city.

The houses were of wooden construction with tile roofs. Many of the industrial buildings also were of wood frame construction. The city as a whole was highly susceptible to fire damage.

Some of the reinforced concrete buildings were of a far stronger construction than is required by normal standards in America, because of the earthquake danger in Japan. This exceptionally strong construction undoubtedly accounted for the fact that the framework of some of the buildings which were fairly close to the center of damage in the city did not collapse.

The population of Hiroshima had reached a peak of over 380,000 earlier in the war but prior to the atomic bombing the population had steadily decreased because of a systematic evacuation ordered by the Japanese government. At the time of the attack the population was approximately 255,000. This figure is based on the registered population, used by the Japanese in computing ration quantities, and the estimates of additional workers and troops who were brought into the city may not be highly accurate. Hiroshima thus had approximately the same number of people as the city of Providence, R.I., or Dallas, Tex.

Nagasaki

Nagasaki lies at the head of a long bay which forms the best natural harbor on the southern Japanese home island of Kyushu. The main commercial and residential area of the city lies on a small plain near the end of the bay. Two rivers divided by a mountain spur form the two main valleys in which the city lies. This mountain spur and the irregular lay-out of the city tremendously reduced the area of destruction, so that at first glance Nagasaki appeared to have been less devastated than Hiroshima.

The heavily build-up area of the city is confined by the terrain to less than 4 square miles out of a total of about 35 square miles in the city as a whole.

The city of Nagasaki had been one of the largest sea ports in southern Japan and was of great war-time importance because of its many and varied industries, including the production of ordnance, ships, military equipment, and other war materials. The narrow long strip attacked was of particular importance because of its industries.

In contrast to many modern aspects of Nagasaki, the residences almost without exception were of flimsy, typical Japanese construction, consisting of wood or wood-frame buildings, with wood walls with or without plaster, and tile roofs. Many of the smaller industries and business establishments were also housed in wooden buildings or flimsily built masonry buildings. Nagasaki had been permitted to grow for many years without conforming to any definite city zoning plan and therefore residences were constructed adjacent to factory buildings and to each other almost as close as it was possible to build them throughout the entire industrial valley.

THE ATTACKS

Hiroshima

Hiroshima was the primary target of the first atomic bomb mission. The mission went smoothly in every respect. The weather was good, and the crew and equipment functioned perfectly. In every detail, the attack was carried out exactly as planned, and the bomb performed exactly as expected.
The bomb exploded over Hiroshima at 8:15 on the morning of August 6, 1945. About an hour previously, the Japanese early warning radar net had detected the approach of some American aircraft headed for the southern part of Japan. The alert had been given and radio broadcasting stopped in many cities, among them Hiroshima. The planes approached the coast at a very high altitude. At nearly 8:00 A.M., the radar operator in Hiroshima determined that the number of planes coming in was very small - probably not more than three - and the air raid alert was lifted. The normal radio broadcast warning was given to the people that it might be advisable to go to shelter if B-29's were actually sighted, but no raid was expected beyond some sort of reconnaissance. At 8:15 A.M., the bomb exploded with a blinding flash in the sky, and a great rush of air and a loud rumble of noise extended for many miles around the city; the first blast was soon followed by the sounds of falling buildings and of growing fires, and a great cloud of dust and smoke began to cast a pall of darkness over the city.

At 8:16 A.M., the Tokyo control operator of the Japanese Broadcasting Corporation noticed that the Hiroshima station had gone off the air. He tried to use another telephone line to reestablish his program, but it too had failed. About twenty minutes later the Tokyo railroad telegraph center realized that the main line telegraph had stopped working just north of Hiroshima. From some small railway stops within ten miles of the city there came unofficial and confused reports of a terrible explosion in Hiroshima. All these reports were transmitted to the Headquarters of the Japanese General Staff.

Military headquarters repeatedly tried to call the Army Control Station in Hiroshima. The complete silence from that city puzzled the men at Headquarters; they knew that no large enemy raid could have occurred, and they knew that no sizeable store of explosives was in Hiroshima at that time. A young officer of the Japanese General Staff was instructed to fly immediately to Hiroshima, to land, survey the damage, and return to Tokyo with reliable information for the staff. It was generally felt at Headquarters that nothing serious had taken place, that it was all a terrible rumor starting from a few sparks of truth.

The staff officer went to the airport and took off for the southwest. After flying for about three hours, while still nearly 100 miles from Hiroshima, he and his pilot saw a great cloud of smoke from the bomb. In the bright afternoon, the remains of Hiroshima were burning.

Their plane soon reached the city, around which they circled in disbelief. A great scar on the land, still burning, and covered by a heavy cloud of smoke, was all that was left of a great city. They landed south of the city, and the staff officer immediately began to organize relief measures, after reporting to Tokyo.

Tokyo's first knowledge of what had really caused the disaster came from the White House public announcement in Washington sixteen hours after Hiroshima had been hit by the atomic bomb.

Nagasaki

Nagasaki had never been subjected to large scale bombing prior to the explosion of the atomic bomb there. On August 1st, 1945, however, a number of high explosive bombs were dropped on the city. A few of these bombs hit in the shipyards and dock areas in the southwest portion of the city. Several of the bombs hit the Mitsubishi Steel and Arms Works and six bombs landed at the Nagasaki Medical School and Hospital, with three direct hits on buildings there. While the damage from these few bombs were relatively small, it created considerable concern in Nagasaki and a number of people, principally school children, were evacuated to rural areas for safety, thus reducing the population in the city at the time of the atomic attack.

On the morning of August 9th, 1945, at about 7:50 A.M., Japanese time, an air raid alert was sounded in Nagasaki, but the "All clear" signal was given at 8:30. When only two B-29 superfortresses were sighted at 10:53 the Japanese apparently assumed that the planes were only on reconnaissance and no further alarm was given. A few moments later, at 11:00 o'clock, the observation B-29 dropped instruments attached to three parachutes and at 11:02 the other plane released the atomic bomb.

The bomb exploded high over the industrial valley of Nagasaki, almost midway between the Mitsubishi Steel and Arms Works, in the south, and the Mitsubishi-Urakami Ordnance Works (Torpedo Works), in the north, the two principal targets of the city.

Despite its extreme importance, the first bombing mission on Hiroshima had been almost routine. The second mission was not so uneventful. Again the crew was specially trained and selected; but bad weather introduced some momentous complications. These complications are best described in the brief account of the mission's weaponeer, Comdr., now Capt., F. L. Ashworth, U.S.N., who was in technical command of the bomb and was charged with the responsibility of insuring that the bomb was successfully dropped at the proper time and on the designated target. His narrative runs as follows:

"The night of our take-off was one of tropical rain squalls, and flashes of lightning stabbed into the darkness with disconcerting regularity. The weather forecast told us of storms all the way from the Marianas to the Empire. Our rendezvous was to be off the southeast coast of Kyushu, some 1500 miles away. There we were to join with our two companion observation B-29's that took off a few minutes behind us. Skillful piloting and expert navigation brought us to the rendezvous without incident.

"About five minutes after our arrival, we were joined by the first of our B-29's. The second, however, failed to arrive, having apparently been thrown off its course by storms during the night. We waited 30 minutes and then proceeded without the second plane toward the target area.

"During the approach to the target the special instruments installed in the plane told us that the bomb was ready to function. We were prepared to drop the second atomic bomb on Japan. But fate was against us, for the target was completely obscured by smoke and haze. Three times we attempted bombing runs, but without success. Then with anti-aircraft fire bursting around us and with a number of enemy fighters coming up after us, we headed for our secondary target, Nagasaki.

"The bomb burst with a blinding flash and a huge column of black smoke swirled up toward us. Out of this column of smoke there boiled a great swirling mushroom of gray smoke, luminous with red, flashing flame, that reached to 40,000 feet in less than 8 minutes. Below through the clouds we could see the pall of black smoke ringed with fire that covered what had been the industrial area of Nagasaki.

"By this time our fuel supply was dangerously low, so after one quick circle of Nagasaki, we headed direct for Okinawa for an emergency landing and refueling".

GENERAL COMPARISON OF HIROSHIMA AND NAGASAKI

It was not at first apparent to even trained observers visiting the two Japanese cities which of the two bombs had been the most effective.

In some respects, Hiroshima looked worse than Nagasaki. The fire damage in Hiroshima was much more complete; the center of the city was hit and everything but the reinforced concrete buildings had virtually disappeared. A desert of clear-swept, charred remains, with only a few strong building frames left standing was a terrifying sight.

At Nagasaki there were no buildings just underneath the center of explosion. The damage to the Mitsubishi Arms Works and the Torpedo Works was spectacular, but not overwhelming. There was something left to see, and the main contours of some of the buildings were still normal.

An observer could stand in the center of Hiroshima and get a view of the most of the city; the hills prevented a similar overall view in Nagasaki. Hiroshima impressed itself on one's mind as a vast expanse of desolation; but nothing as vivid was left in one's memory of Nagasaki.

When the observers began to note details, however, striking differences appeared. Trees were down in both cities, but the large trees which fell in Hiroshima were uprooted, while those in Nagasaki were actually snapped off. A few reinforced concrete buildings were smashed at the center in Hiroshima, but in Nagasaki equally heavy damage could be found 2,300 feet from X. In the study of objects which gave definite clues to the blast pressure, such as squashed tin cans, dished metal plates, bent or snapped poles and like, it was soon evident that the Nagasaki bomb had been much more effective than the Hiroshima bomb. In the description of damage which follows, it will be noted that the radius for the amount of damage was greater in Nagasaki than Hiroshima.

GENERAL DESCRIPTION OF DAMAGE CAUSED BY THE ATOMIC EXPLOSIONS

In considering the devastation in the two cities, it should be remembered that the cities' differences in shape and topography resulted in great differences in the damages. Hiroshima was all on low, flat ground, and was roughly circular in shape; Nagasaki was much cut up by hills and mountain spurs, with no regularity to its shape.

In Hiroshima almost everything up to about one mile from X was completely destroyed, except for a small number (about 50) of heavily reinforced concrete buildings, most of which were specially designed to withstand earthquake shock, which were not collapsed by the blast; most of these buildings had their interiors completely gutted, and all windows, doors, sashes, and frames ripped out. In Nagasaki, nearly everything within 1/2 mile of the explosion was destroyed, including heavy structures. All Japanese homes were destroyed within 1 1/2 miles from X.

Underground air raid shelters with earth cover roofs immediately below the explosion had their roofs caved in; but beyond 1/2 mile from X they suffered no damage.

In Nagasaki, 1500 feet from X high quality steel frame buildings were not completely collapsed, but the entire buildings suffered mass distortion and all panels and roofs were blown in.

In Nagasaki, 2,000 feet from X, reinforced concrete buildings with 10" walls and 6" floors were collapsed; reinforced concrete buildings with 4" walls and roofs were standing but were badly damaged. At 2,000 feet some 9" concrete walls were completely destroyed.

In Nagasaki, 3,500 feet from X, church buildings with 18" brick walls were completely destroyed. 12" brick walls were severely cracked as far as 5,000 feet.

In Hiroshima, 4,400 feet from X, multi-story brick buildings were completely demolished. In Nagasaki, similar buildings were destroyed to 5,300 feet.

In Hiroshima, roof tiles were bubbled (melted) by the flash heat out to 4,000 feet from X; in Nagasaki, the same effect was observed to 6,500 feet.

In Hiroshima, steel frame buildings were destroyed 4,200 feet from X, and to 4,800 feet in Nagasaki.

In both cities, the mass distortion of large steel buildings was observed out to 4,500 feet from X.

In Nagasaki, reinforced concrete smoke stacks with 8" walls, specially designed to withstand earthquake shocks, were overturned up to 4,000 feet from X.

In Hiroshima, steel frame buildings suffered severe structural damage up to 5,700 feet from X, and in Nagasaki the same damage was sustained as far as 6,000 feet.

In Nagasaki, 9" brick walls were heavily cracked to 5,000 feet, were moderately cracked to 6,000 feet, and slightly cracked to 8,000 feet. In both cities, light concrete buildings collapsed out to 4,700 feet.

In Hiroshima, multi-story brick buildings suffered structural damage up to 6,600 feet, and in Nagasaki up to 6,500 feet from X.

In both cities overhead electric installations were destroyed up to 5,500 feet; and trolley cars were destroyed up to 5,500 feet, and damaged to 10,500 feet.

Flash ignition of dry, combustible material was observed as far as 6,400 feet from X in Hiroshima, and in Nagasaki as far as 10,000 feet from X.

Severe damage to gas holders occured out to 6,500 feet in both cities.

All Japanese homes were seriously damaged up to 6,500 feet in Hiroshima, and to 8,000 feet in Nagasaki. Most Japanese homes were damaged up to 8,000 feet in Hiroshima and 10,500 feet in Nagasaki.

The hillsides in Nagasaki were scorched by the flash radiation of heat as far as 8,000 feet from X; this scorching gave the hillsides the appearance of premature autumn.

In Nagasaki, very heavy plaster damage was observed in many buildings up to 9,000 feet; moderate damage was sustained as far as 12,000 feet, and light damage up to 15,000 feet.

The flash charring of wooden telegraph poles was observed up to 9,500 feet from X in Hiroshima, and to 11,000 feet in Nagasaki; some reports indicate flash burns as far as 13,000 feet from X in both places.

Severe displacement of roof tiles was observed up to 8,000 feet in Hiroshima, and to 10,000 feet in Nagasaki.

In Nagasaki, very heavy damage to window frames and doors was observed up to 8,000 feet, and light damage up to 12,000 feet.

Roofs and wall coverings on steel frame buildings were destroyed out to 11,000 feet.

Although the sources of many fires were difficult to trace accurately, it is believed that fires were started by primary heat radiation as far as 15,000 feet from X.

Roof damage extended as far as 16,000 feet from X in Hiroshima and in Nagasaki.

The actual collapse of buildings was observed at the extreme range of 23,000 feet from X in Nagasaki.

Although complete window damage was observed only up to 12,000 feet from X, some window damage occurred in Nagasaki up to 40,000 feet, and actual breakage of glass occured up to 60,000 feet.

Heavy fire damage was sustained in a circular area in Hiroshima with a mean radius of about 6,000 feet and a maximum radius of about 11,000 feet; similar heavy damage occured in Nagasaki south of X up to 10,000 feet, where it was stopped on a river course.

In Hiroshima over 60,000 of 90,000 buildings were destroyed or severely damaged by the atomic bomb; this figure represents over 67% of the city's structures.

In Nagasaki 14,000 or 27% of 52,000 residences were completely destroyed and 5,40O, or 10% were half destroyed. Only 12% remained undamaged. This destruction was limited by the layout of the city. The following is a summary of the damage to buildings in Nagasaki as determined from a ground survey made by the Japanese:

(Compiled by Nagasaki Municipality)

Destruction of Buildings and Houses	Number	Percentage
Total in Nagasaki (before atomic explosion)	50,000	100.0
Blasted (not burned)	2,652	5.3
Blasted and burned	11,494	23.0
Blasted and/or burned	14,146	28.3
Partially burned or blasted	5,441	10.9
Total buildings and houses destroyed	19,587	39.2
Undamaged	30,413	60.8

In Hiroshima, all utilities and transportation services were disrupted for varying lengths of time. In general however services were restored about as rapidly as they could be used by the depleted population. Through railroad service was in order in Hiroshima on 8 August, and electric power was available in most of the surviving parts on 7 August, the day after the bombing. The reservoir of the city was not damaged, being nearly 2 miles from X. However, 70,000 breaks in water pipes in buildings and dwellings were caused by the blast and fire effects. Rolling transportation suffered extensive damage. The damage to railroad tracks, and roads was comparatively small, however. The electric power transmission and distribution systems were badly wrecked. The telephone system was approximately 80% damaged, and no service was restored until 15 August.

Despite the customary Japanese lack of attention to sanitation measures, no major epidemic broke out in the bombed cities. Although the conditions following the bombings makes this fact seem surprising, the experience of other bombed cities in both Germany and Japan show Hiroshima and Nagasaki not to be isolated cases.

The atomic explosion over Nagasaki affected an over-all area of approximately 42.9 square miles of which about 8.5 square miles were water and only about 9.8 square miles were built up, the remainder being partially settled. Approximately 36% of the built up areas were seriously damaged. The area most severely damaged had an average radius of about 1 mile, and covered about 2.9 square miles of which 2.4 were built up.

In Nagasaki, buildings with structural steel frames, principally the Mitsubishi Plant as far as 6,000 feet from X were severely damaged; these buildings were typical of wartime mill construction in America and Great Britain, except that some of the frames were somewhat less substantial. The damage consisted of windows broken out (100%), steel sashes ripped out or bent, corrugated metal or corrugated asbestos roofs and sidings ripped off, roofs bent or destroyed, roof trusses collapsed, columns bent and cracked and concrete foundations for columns rotated. Damage to buildings with structural steel frames was more severe where the buildings received the effect of the blast on their sides than where the blast hit the ends of buildings, because the buildings had more stiffness (resistance to negative moment at the top of columns) in a longitudinal direction. Many of the lightly constructed steel frame buildings collapsed completely while some of the heavily constructed (to carry the weight of heavy cranes and loads) were stripped of roof and siding, but the frames were only partially injured.

The next most seriously damaged area in Nagasaki lies outside the 2.9 square miles just described, and embraces approximately 4.2 square miles of which 29% was built up. The damage from blast and fire was moderate here, but in some sections (portions of main business districts) many secondary fires started and spread rapidly, resulting in about as much over-all destruction as in areas much closer to X.

An area of partial damage by blast and fire lies just outside the one just described and comprises approximately 35.8 square miles. Of this area, roughly 1/6th was built up and 1/4th was water. The extent of damage varied from serious (severe damage to roofs and windows in the main business section of Nagasaki, 2.5 miles from X), to minor (broken or occasionally broken windows at a distance of 7 miles southeast of X).

As intended, the bomb was exploded at an almost ideal location over Nagasaki to do the maximum damage to industry, including the Mitsubishi Steel and Arms Works, the Mitsubishi-Urakami Ordnance Works (Torpedo Works), and numerous factories, factory training schools, and other industrial establishments, with a minimum destruction of dwellings and consequently, a minimum amount of casualties. Had the bomb been dropped farther south, the Mitsubishi-Urakami Ordnance Works would not have been so severely damaged, but the main business and residential districts of Nagasaki would have sustained much greater damage casualties.

Calculations show that the structural steel and reinforced concrete frames which survived the blast fairly close to X could not have withstood the estimated peak pressures developed against the total areas presented by the sides and roof of the buildings. The survival of these frames is explained by the fact that they were not actually required to withstand the peak pressure because the windows were quickly knocked out and roof and siding stripped off thereby reducing total area and relieving the pressure. While this saved the building frame, it permitted severe damage to building interior and contents, and injuries to the building occupants. Buildings without large panel openings through which the pressure could dissipate were completely crushed, even when their frames were as strong as those which survived.

The damage sustained by reinforced concrete buildings depended both on the proximity to X and the type and strength of the reinforced concrete construction. Some of the buildings with reinforced concrete frames also had reinforced concrete walls, ceilings, and partitions, while others had brick or concrete tile walls covered either with plaster or ornamental stone, with partitions of metal, glass, and plaster. With the exception of the Nagasaki Medical School and Hospital group, which was designed to withstand earthquakes and was therefore of heavier construction than most American structures, most of the reinforced concrete structures could be classified only as fair, with concrete of low strength and density, with many of the columns, beams, and slabs underdesigned and improperly reinforced. These facts account for some of the structural failures which occured.

In general, the atomic bomb explosion damaged all windows and ripped out, bent, or twisted most of the steel window or door sashes, ripped doors from hinges, damaged all suspended wood, metal, and plaster ceilings. The blast concussion also caused great damage to equipment by tumbling and battering. Fires generally of secondary origin consumed practically all combustible material, caused plaster to crack off, burned all wooden trim, stair covering, wooden frames of wooden suspended ceilings, beds, mattresses, and mats, and fused glass, ruined all equipment not already destroyed by the blast, ruined all electrical wiring, plumbing, and caused spalling of concrete columns and beams in many of the rooms.

Almost without exception masonry buildings of either brick or stone within the effective limits of the blast were severely damaged so that most of them were flattened or reduced to rubble. The wreckage of a church, approximately 1,800 feet east of X in Nagasaki, was one of the few masonry buildings still recognizable and only portions of the walls of this structure were left standing. These walls were extremely thick (about 2 feet). The two domes of the church had reinforced concrete frames and although they were toppled, they held together as units.

Practically every wooden building or building with timber frame within 2.0 miles of X was either completely destroyed or very seriously damaged, and significant damage in Nagasaki resulted as far as 3 miles from X. Nearly all such buildings collapsed and a very large number were consumed by fire.

A reference to the various photographs depicting damage shows that although most of the buildings within the effective limits of the blast were totally destroyed or severely damaged, a large number of chimneys even close to X were left standing, apparently uninjured by the concussion. One explanation is that concrete chimneys are approximately cylindrical in shape and consequently offer much less wind resistance than flat surfaces such as buildings. Another explanation is that since the cities were subject to typhoons the more modern chimneys were probably designed to withstand winds of high velocity. It is also probable that most of the recently constructed chimneys as well as the more modern buildings were constructed to withstand the acceleration of rather severe earthquakes. Since the bombs were exploded high in the air, chimneys relatively close to X were subjected to more of a downward than a lateral pressure, and consequently the overturning moment was much less than might have been anticipated.

Although the blast damaged many bridges to some extent, bridge damage was on the whole slight in comparison to that suffered by buildings. The damage varied from only damaged railings to complete destruction of the superstructure. Some of the bridges were wrecked and the spans were shoved off their piers and into the river bed below by the force of the blast. Others, particularly steel plate girder bridges, were badly buckled by the blast pressure. None of the failures observed could be attributed to inadequate design or structural weaknesses.

The roads, and railroad and street railway trackage sustained practically no primary damage as a result of the explosion. Most of the damage to railroads occurred from secondary causes, such as fires and damage to bridges or other structures. Rolling stock, as well as automobiles, trolleys, and buses were destroyed and burned up to a considerable distance from X. Streets were impassable for awhile because of the debris, but they were not damaged. The height of the bomb explosion probably explains the absence of direct damage to railroads and roads.

A large part of the electric supply was interrupted by the bomb blast chiefly through damage to electric substations and overhead transmission systems. Both gas works in Nagasaki were severely damaged by the bomb. These works would have required 6-7 months to get into operation. In addition to the damage sustained by the electrical and gas systems, severe damage to the water supply system was reported by the Japanese government; the chief damage was a number of breaks in the large water mains and in almost all of the distributing pipes in the areas which were affected by the blast. Nagasaki was still suffering from a water shortage inside the city six weeks after the atomic attack.

The Nagasaki Prefectural report describes vividly the effects of the bomb on the city and its inhabitants:

"Within a radius of 1 kilometer from X, men and animals died almost instantaneously and outside a radius of 1 kilometer and within a radius of 2 kilometers from X, some men and animals died instantly from the great blast and heat but the great majority were seriously or superficially injured. Houses and other structures were completely destroyed while fires broke out everywhere. Trees were uprooted and withered by the heat.

"Outside a radius of 2 kilometers and within a radius of 4 kilometers from X, men and animals suffered various degrees of injury from window glass and other fragments scattered about by the blast and many were burned by the intense heat. Dwellings and other structures were half damaged by blast.

"Outside a radius of 4 kilometers and within a radius of 8 kilometers living creatures were injured by materials blown about by the blast; the majority were only superficially wounded. Houses were only half or partially damaged."

The British Mission to Japan interpreted their observations of the destruction of buildings to apply to similar construction of their own as follows:

A similar bomb exploding in a similar fashion would produce the following effects on normal British houses:

Up to 1,000 yards from X it would cause complete collapse.

Up to 1 mile from X it would damage the houses beyond repair.

Up to 1.5 miles from X it would render them uninhabitable without extensive repair, particularly to roof timbers.

Up to 2.5 miles from X it would render them uninhabitable until first-aid repairs had been carried out.
The fire damage in both cities was tremendous, but was more complete in Hiroshima than in Nagasaki. The effect of the fires was to change profoundly the appearance of the city and to leave the central part bare, except for some reinforced concrete and steel frames and objects such as safes, chimney stacks, and pieces of twisted sheet metal. The fire damage resulted more from the properties of the cities themselves than from those of the bombs.

The conflagration in Hiroshima caused high winds to spring up as air was drawn in toward the center of the burning area, creating a "fire storm". The wind velocity in the city had been less than 5 miles per hour before the bombing, but the fire-wind attained a velocity of 30-40 miles per hour. These great winds restricted the perimeter of the fire but greatly added to the damage of the conflagration within the perimeter and caused the deaths of many persons who might otherwise have escaped. In Nagasaki, very severe damage was caused by fires, but no extensive "fire storm" engulfed the city. In both cities, some of the fires close to X were no doubt started by the ignition of highly combustible material such as paper, straw, and dry cloth, upon the instantaneous radiation of heat from the nuclear explosion. The presence of large amounts of unburnt combustible materials near X, however, indicated that even though the heat of the blast was very intense, its duration was insufficient to raise the temperature of many materials to the kindling point except in cases where conditions were ideal. The majority of the fires were of secondary origin starting from the usual electrical short-circuits, broken gas lines, overturned stoves, open fires, charcoal braziers, lamps, etc., following collapse or serious damage from the direct blast.

Fire fighting and rescue units were stripped of men and equipment. Almost 30 hours elapsed before any rescue parties were observable. In Hiroshima only a handful of fire engines were available for fighting the ensuing fires, and none of these were of first class type. In any case, however, it is not likely that any fire fighting equipment or personnel or organization could have effected any significant reduction in the amount of damage caused by the tremendous conflagration.

A study of numerous aerial photographs made prior to the atomic bombings indicates that between 10 June and 9 August 1945 the Japanese constructed fire breaks in certain areas of the cities in order to control large scale fires. In general these fire breaks were not effective because fires were started at so many locations simultaneously. They appear, however, to have helped prevent fires from spreading farther east into the main business and residential section of Nagasaki.

TOTAL CASUALTIES

There has been great difficulty in estimating the total casualties in the Japanese cities as a result of the atomic bombing. The extensive destruction of civil installations (hospitals, fire and police department, and government agencies) the state of utter confusion immediately following the explosion, as well as the uncertainty regarding the actual population before the bombing, contribute to the difficulty of making estimates of casualties. The Japanese periodic censuses are not complete. Finally, the great fires that raged in each city totally consumed many bodies.

The number of total casualties has been estimated at various times since the bombings with wide discrepancies. The Manhattan Engineer District's best available figures are:

TABLE A

Estimates of Casualties

	Hiroshima	Nagasaki
Pre-raid population	255,000	195,000
Dead	66,000	39,000
Injured	69,000	25,000
Total Casualties	135,000	64,000

The relation of total casualties to distance from X, the center of damage and point directly under the air-burst explosion of the bomb, is of great importance in evaluating the casualty-producing effect of the bombs. This relationship for the total population of Nagasaki is shown in the table below, based on the first-obtained casualty figures of the District:

TABLE B

Relation of Total Casualties to Distance from X

Distance from X feet	Killed	Injured	Missing	Total Casualties	Killed per square mile
0 - 1,640	7,505	960	1,127	9,592	24,7OO
1,640-3,300	3,688	1,478	1,799	6,965	4,040
3,300-4,900	8,678	17,137	3,597	29,412	5,710
4,900 - 6,550	221	11,958	28	12,207	125
6,550 - 9,850	112	9,460	17	9,589	20

No figure for total pre-raid population at these different distances were available. Such figures would be necessary in order to compute per cent mortality. A calculation made by the British Mission to Japan and based on a preliminary analysis of the study of the Joint Medical-Atomic Bomb Investigating Commission gives the following calculated values for per cent mortality at increasing distances from X:

TABLE C

Per-Cent Mortality at Various Distances

Distance from X, in feet	Per-cent Mortality
0 - 1000	93.0%
1000 - 2000	92.0
2000 - 3000	86.0
3000 - 4000	69.0
4000 - 5000	49.0
5000 - 6000	31.5
6000 - 7000	12.5
7000 - 8000	1.3
8000 - 9000	0.5
9000 - 10,000	0.0

It seems almost certain from the various reports that the greatest total number of deaths were those occurring immediately after the bombing. The causes of many of the deaths can only be surmised, and of course many persons near the center of explosion suffered fatal injuries from more than one of the bomb effects. The proper order of importance for possible causes of death is: burns, mechanical injury, and gamma radiation. Early estimates by the Japanese are shown in D below:

TABLE D

Cause of Immediate Deaths

City	Cause of Death	Per-cent of Total
Hiroshima	Burns	60%
	Falling debris	30
	Other	10
Nagasaki	Burns	95%
	Falling debris	9
	Flying glass	7
	Other	7

THE NATURE OF AN ATOMIC EXPLOSION

The most striking difference between the explosion of an atomic bomb and that of an ordinary T.N.T. bomb is of course in magnitude; as the President announced after the Hiroshima attack, the explosive energy of each of the atomic bombs was equivalent to about 20,000 tons of T.N.T.

But in addition to its vastly greater power, an atomic explosion has several other very special characteristics. Ordinary explosion is a chemical reaction in which energy is released by the rearrangement of the atoms of the explosive material. In an atomic explosion the identity of the atoms, not simply their arrangement, is changed. A considerable fraction of the mass of the explosive charge, which may be uranium 235 or plutonium, is transformed into energy. Einstein's equation, E = mc², shows that matter that is transformed into energy may yield a total energy equivalent to the mass multiplied by the square of the velocity of light. The significance of the equation is easily seen when one recalls that the velocity of light is 186,000 miles per second. The energy released when a pound of T.N.T. explodes would, if converted entirely into heat, raise the temperature of 36 lbs. of water from freezing temperature (32F) to boiling temperature (212F). The nuclear fission of a pound of uranium would produce an equal temperature rise in over 200 million pounds of water.

The explosive effect of an ordinary material such as T.N.T. is derived from the rapid conversion of solid T.N.T. to gas, which occupies initially the same volume as the solid; it exerts intense pressures on the surrounding air and expands rapidly to a volume many times larger than the initial volume. A wave of high pressure thus rapidly moves outward from the center of the explosion and is the major cause of damage from ordinary high explosives. An atomic bomb also generates a wave of high pressure which is in fact of, much higher pressure than that from ordinary explosions; and this wave is again the major cause of damage to buildings and other structures. It differs from the pressure wave of a block buster in the size of the area over which high pressures are generated. It also differs in the duration of the pressure pulse at any given point: the pressure from a blockbuster lasts for a few milliseconds (a millisecond is one thousandth of a second) only, that from the atomic bomb for nearly a second, and was felt by observers both in Japan and in New Mexico as a very strong wind going by.

The next greatest difference between the atomic bomb and the T.N.T. explosion is the fact that the atomic bomb gives off greater amounts of radiation. Most of this radiation is "light" of some wave-length ranging from the so-called heat radiations of very long wave length to the so-called gamma rays which have wave­lengths even shorter than the X-rays used in medicine. All of these radiations travel at the same speed; this, the speed of light, is 186,000 miles per second. The radiations are intense enough to kill people within an appreciable distance from the explosion, and are in fact the major cause of deaths and injuries apart from mechanical injuries. The greatest number of radiation injuries was probably due to the ultra-violet rays which have a wave length slightly shorter than visible light and which caused flash burn comparable to severe sunburn. After these, the gamma rays of ultra short wave length are most important; these cause injuries similar to those from over-doses of X-rays.

The origin of the gamma rays is different from that of the bulk of the radiation: the latter is caused by the extremely high temperatures in the bomb, in the same way as light is emitted from the hot surface of the sun or from the wires in an incandescent lamp. The gamma rays on the other hand are emitted by the atomic nuclei themselves when they are transformed in the fission process. The gamma rays are therefore specific to the atomic bomb and are completely absent in T.N.T. explosions. The light of longer wave length (visible and ultra-violet) is also emitted by a T.N.T. explosion, but with much smaller intensity than by an atomic bomb, which makes it insignificant as far as damage is concerned.

A large fraction of the gamma rays is emitted in the first few microseconds (millionths of a second) of the atomic explosion, together with neutrons which are also produced in the nuclear fission. The neutrons have much less damage effect than the gamma rays because they have a smaller intensity and also because they are strongly absorbed in air and therefore can penetrate only to relatively small distances from the explosion: at a thousand yards the neutron intensity is negligible. After the nuclear emission, strong gamma radiation continues to come from the exploded bomb. This generates from the fission products and continues for about one minute until all of the explosion products have risen to such a height that the intensity received on the ground is negligible. A large number of beta rays are also emitted during this time, but they are unimportant because their range is not very great, only a few feet. The range of alpha particles from the unused active material and fissionable material of the bomb is even smaller.

Apart from the gamma radiation ordinary light is emitted, some of which is visible and some of which is the ultra violet rays mainly responsible for flash burns. The emission of light starts a few milliseconds after the nuclear explosion when the energy from the explosion reaches the air surrounding the bomb. The observer sees then a ball of fire which rapidly grows in size. During most of the early time, the ball of fire extends as far as the wave of high pressure. As the ball of fire grows its temperature and brightness decrease. Several milliseconds after the initiation of the explosion, the brightness of the ball of fire goes through a minimum, then it gets somewhat brighter and remains at the order of a few times the brightness of the sun for a period of 10 to 15 seconds for an observer at six miles distance. Most of the radiation is given off after this point of maximum brightness. Also after this maximum, the pressure waves run ahead of the ball of fire.

The ball of fire rapidly expands from the size of the bomb to a radius of several hundred feet at one second after the explosion. After this the most striking feature is the rise of the ball of fire at the rate of about 30 yards per second. Meanwhile it also continues to expand by mixing with the cooler air surrounding it. At the end of the first minute the ball has expanded to a radius of several hundred yards and risen to a height of about one mile. The shock wave has by now reached a radius of 15 miles and its pressure dropped to less than 1/10 of a pound per square inch. The ball now loses its brilliance and appears as a great cloud of smoke: the pulverized material of the bomb. This cloud continues to rise vertically and finally mushrooms out at an altitude of about 25,000 feet depending upon meteorological conditions. The cloud reaches a maximum height of between 50,000 and 70,000 feet in a time of over 30 minutes.

It is of interest to note that Dr. Hans Bethe, then a member of the Manhattan Engineer District on loan from Cornell University, predicted the existence and characteristics of this ball of fire months before the first test was carried out.

To summarize, radiation comes in two bursts - an extremely intense one lasting only about 3 milliseconds and a less intense one of much longer duration lasting several seconds. The second burst contains by far the larger fraction of the total light energy, more than 90%. But the first flash is especially large in ultra-violet radiation which is biologically more effective. Moreover, because the heat in this flash comes in such a short time, there is no time for any cooling to take place, and the temperature of a person's skin can be raised 50 degrees centigrade by the flash of visible and ultra-violet rays in the first millisecond at a distance of 4,000 yards. People may be injured by flash burns at even larger distances. Gamma radiation danger does not extend nearly so far and neutron radiation danger is still more limited.

The high skin temperatures result from the first flash of high intensity radiation and are probably as significant for injuries as the total dosages which come mainly from the second more sustained burst of radiation. The combination of skin temperature increase plus large ultra-violet flux inside 4,000 yards is injurious in all cases to exposed personnel. Beyond this point there may be cases of injury, depending upon the individual sensitivity. The infra-red dosage is probably less important because of its smaller intensity.

CHARACTERISTICS OF THE DAMAGE CAUSED BY THE ATOMIC BOMBS

The damage to man-made structures caused by the bombs was due to two distinct causes: first the blast, or pressure wave, emanating from the center of the explosion, and, second, the fires which were caused either by the heat of the explosion itself or by the collapse of buildings containing stoves, electrical fixtures, or any other equipment which might produce what is known as a secondary fire, and subsequent spread of these fires.

The blast produced by the atomic bomb has already been stated to be approximately equivalent to that of 20,000 tons of T.N.T. Given this figure, one may calculate the expected peak pressures in the air, at various distances from the center of the explosion, which occurred following detonation of the bomb. The peak pressures which were calculated before the bombs were dropped agreed very closely with those which were actually experienced in the cities during the attack as computed by Allied experts in a number of ingenious ways after the occupation of Japan.

The blast of pressure from the atomic bombs differed from that of ordinary high explosive bombs in three main ways:

A. Downward thrust. Because the explosions were well up in the air, much of the damage resulted from a downward pressure. This pressure of course most largely effected flat roofs. Some telegraph and other poles immediately below the explosion remained upright while those at greater distances from the center of damage, being more largely exposed to a horizontal thrust from the blast pressure waves, were overturned or tilted. Trees underneath the explosion remained upright but had their branches broken downward.

B. Mass distortion of buildings. An ordinary bomb can damage only a part of a large building, which may then collapse further under the action of gravity. But the blast wave from an atomic bomb is so large that it can engulf whole buildings, no matter how great their size, pushing them over as though a giant hand had given them a shove.

C. Long duration of the positive pressure pulse and consequent small effect of the negative pressure, or suction, phase. In any explosion, the positive pressure exerted by the blast lasts for a definite period of time (usually a small fraction of a second) and is then followed by a somewhat longer period of negative pressure, or suction. The negative pressure is always much weaker than the positive, but in ordinary explosions the short duration of the positive pulse results in many structures not having time to fail in that phase, while they are able to fail under the more extended, though weaker, negative pressure. But the duration of the positive pulse is approximately proportional to the 1/3 power of the size of the explosive charge. Thus, if the relation held true throughout the range in question, a 10-ton T.N.T. explosion would have a positive pulse only about 1/14th as long as that of a 20,000-ton explosion. Consequently, the atomic explosions had positive pulses so much longer then those of ordinary explosives that nearly all failures probably occurred during this phase, and very little damage could be attributed to the suction which followed.

One other interesting feature was the combination of flash ignition and comparative slow pressure wave. Some objects, such as thin, dry wooden slats, were ignited by the radiated flash heat, and then their fires were blown out some time later (depending on their distance from X) by the pressure blast which followed the flash radiation.

CALCULATIONS OF THE PEAK PRESSURE OF THE BLAST WAVE

Several ingenious methods were used by the various investigators to determine, upon visiting the wrecked cities, what had actually been the peak pressures exerted by the atomic blasts. These pressures were computed for various distances from X, and curves were then plotted which were checked against the theoretical predictions of what the pressures would be. A further check was afforded from the readings obtained by the measuring instruments which were dropped by parachute at each atomic attack. The peak pressure figures gave a direct clue to the equivalent T.N.T. tonnage of the atomic bombs, since the pressures developed by any given amount of T.N.T. can be calculated easily.

One of the simplest methods of estimating the peak pressure is from crushing of oil drums, gasoline cans, or any other empty thin metal vessel with a small opening. The assumption made is that the blast wave pressure comes on instantaneously, the resulting pressure on the can is more than the case can withstand, and the walls collapse inward. The air inside is compressed adiabatically to such a point that the pressure inside is less by a certain amount than the pressure outside, this amount being the pressure difference outside and in that the walls can stand in their crumpled condition. The uncertainties involved are, first, that some air rushes in through any opening that the can may have, and thus helps to build up the pressure inside; and, second, that as the pressure outside falls, the air inside cannot escape sufficiently fast to avoid the walls of the can being blown out again to some extent. These uncertainties are such that estimates of pressure based on this method are on the low side, i.e., they are underestimated.

Another method of calculating the peak-pressure is through the bending of steel flagpoles, or lightning conductors, away from the explosion. It is possible to calculate the drag on a pole or rod in an airstream of a certain density and velocity; by connecting this drag with the strength of the pole in question, a determination of the pressure wave may be obtained.

Still another method of estimating the peak pressure is through the overturning of memorial stones, of which there are a great quantity in Japan. The dimensions of the stones can be used along with known data on the pressure exerted by wind against flat surfaces, to calculate the desired figure.

LONG RANGE BLAST DAMAGE

There was no consistency in the long range blast damage. Observers often thought that they had found the limit, and then 2,000 feet farther away would find further evidence of damage.
The most impressive long range damage was the collapse of some of the barracks sheds at Kamigo, 23,000 feet south of X in Nagasaki. It was remarkable to see some of the buildings intact to the last details, including the roof and even the windows, and yet next to them a similar building collapsed to ground level.

The limiting radius for severe displacement of roof tiles in Nagasaki was about 10,000 feet although isolated cases were found up to 16,000 feet. In Hiroshima the general limiting radius was about 8,000 feet; however, even at a distance of 26,000 feet from X in Hiroshima, some tiles were displaced.
At Mogi, 7 miles from X in Nagasaki, over steep hills over 600 feet high, about 10% of the glass came out. In nearer, sequestered localities only 4 miles from X, no damage of any kind was caused. An interesting effect was noted at Mogi; eyewitnesses said that they thought a raid was being made on the place; one big flash was seen, then a loud roar, followed at several second intervals by half a dozen other loud reports, from all directions. These successive reports were obviously reflections from the hills surrounding Mogi.

GROUND SHOCK

The ground shock in most cities was very light. Water pipes still carried water and where leaks were visible they were mainly above ground. Virtually all of the damage to underground utilities was caused by the collapse of buildings rather than by any direct exertion of the blast pressure. This fact of course resulted from the bombs' having been exploded high in the air.

SHIELDING, OR SCREENING FROM BLAST

In any explosion, a certain amount of protection from blast may be gained by having any large and substantial object between the protected object and the center of the explosion. This shielding effect was noticeable in the atomic explosions, just as in ordinary cases, although the magnitude of the explosions and the fact that they occurred at a considerable height in the air caused marked differences from the shielding which would have characterized ordinary bomb explosions.

The outstanding example of shielding was that afforded by the hills in the city of Nagasaki; it was the shielding of these hills which resulted in the smaller area of devastation in Nagasaki despite the fact that the bomb used there was not less powerful. The hills gave effective shielding only at such distances from the center of explosion that the blast pressure was becoming critical - that is, was only barely sufficient to cause collapse - for the structure. Houses built in ravines in Nagasaki pointing well away from the center of the explosion survived without damage, but others at similar distances in ravines pointing toward the center of explosion were greatly damaged. In the north of Nagasaki there was a small hamlet about 8,000 feet from the center of explosion; one could see a distinctive variation in the intensity of damage across the hamlet, corresponding with the shadows thrown by a sharp hill.

The best example of shielding by a hill was southeast of the center of explosion in Nagasaki. The damage at 8,000 feet from X consisted of light plaster damage and destruction of about half the windows. These buildings were of European type and were on the reverse side of a steep hill. At the same distance to the south-southeast the damage was considerably greater, i.e., all windows and frames, doors, were damaged and heavy plaster damage and cracks in the brick work also appeared. The contrast may be illustrated also by the fact that at the Nagasaki Prefectural office at 10,800 feet the damage was bad enough for the building to be evacuated, while at the Nagasaki Normal School to which the Prefectural office had been moved, at the same distance, the damage was comparatively light.

Because of the height of the bursts no evidence was expected of the shielding of one building by another, at least up to a considerable radius. It was in fact difficult to find any evidence at any distance of such shielding. There appeared to have been a little shielding of the building behind the Administration Building of the Torpedo Works in Nagasaki, but the benefits were very slight. There was also some evidence that the group of buildings comprising the Medical School in Nagasaki did afford each other mutual protection. On the whole, however, shielding of one building by another was not noticeable.

There was one other peculiar type of shielding, best exhibited by the workers' houses to the north of the torpedo plant in Nagasaki. These were 6,000 to 7,000 feet north of X. The damage to these houses was not nearly as bad as those over a thousand feet farther away from the center of explosion. It seemed as though the great destruction caused in the torpedo plant had weakened the blast a little, and the full power was not restored for another 1,000 feet or more.

FLASH BURN

As already stated, a characteristic feature of the atomic bomb, which is quite foreign to ordinary explosives, is that a very appreciable fraction of the energy liberated goes into radiant heat and light. For a sufficiently large explosion, the flash burn produced by this radiated energy will become the dominant cause of damage, since the area of burn damage will increase in proportion to the energy released, whereas the area of blast damage increases only with the two-thirds power of the energy. Although such a reversal of the mechanism of damage was not achieved in the Hiroshima and Nagasaki bombs, the effects of the flash were, however, very evident, and many casualties resulted from flash burns. A discussion of the casualties caused by flash burns will be given later; in this section will be described the other flash effects which were observed in the two cities.

The duration of the heat radiation from the bomb is so short, just a few thousandths of a second, that there is no time for the energy falling on a surface to be dissipated by thermal defusion; the flash burn is typically a surface effect. In other words the surface of either a person or an object exposed to the flash is raised to a very high temperature while immediately beneath the surface very little rise in temperature occurs.

The flash burning of the surface of objects, particularly wooden objects, occurred in Hiroshima up to a radius of 9,500 feet from X; at Nagasaki burns were visible up to 11,000 feet from X. The charring and blackening of all telephone poles, trees and wooden posts in the areas not destroyed by the general fire occurred only on the side facing the center of explosion and did not go around the corners of buildings or hills. The exact position of the explosion was in fact accurately determined by taking a number of sights from various objects which had been flash burned on one side only.

To illustrate the effects of the flash burn, the following describes a number of examples found by an observer moving northward from the center of explosion in Nagasaki. First occurred a row of fence posts at the north edge of the prison hill, at 0.3 miles from X. The top and upper part of these posts were heavily charred. The charring on the front of the posts was sharply limited by the shadow of a wall. This wall had however been completely demolished by the blast, which of course arrived some time after the flash. At the north edge of the Torpedo works, 1.05 miles from X, telephone poles were charred to a depth of about 0.5 millimeters. A light piece of wood similar to the flat side of an orange crate, was found leaning against one of the telephone poles. Its front surface was charred the same way as the pole, but it was evident that it had actually been ignited. The wood was blackened through a couple of cracks and nail holes, and around the edges onto the back surface. It seemed likely that this piece of wood had flamed up under the flash for a few seconds before the flame was blown out by the wind of the blast. Farther out, between 1.05 and 1.5 miles from the explosion, were many trees and poles showing a blackening. Some of the poles had platforms near the top. The shadows cast by the platforms were clearly visible and showed that the bomb had detonated at a considerable height. The row of poles turned north and crossed the mountain ridge; the flash burn was plainly visible all the way to the top of the ridge, the farthest burn observed being at 2.0 miles from X.

Another striking effect of the flash burn was the autumnal appearance of the bowl formed by the hills on three sides of the explosion point. The ridges are about 1.5 miles from X. Throughout this bowl the foliage turned yellow, although on the far side of the ridges the countryside was quite green. This autumnal appearance of the trees extended to about 8,000 feet from X.

However, shrubs and small plants quite near the center of explosion in Hiroshima, although stripped of leaves, had obviously not been killed. Many were throwing out new buds when observers visited the city.

There are two other remarkable effects of the heat radiated from the bomb explosion. The first of these is the manner in which heat roughened the surface of polished granite, which retained its polish only where it was shielded from the radiated heat travelling in straight lines from the explosion. This roughening by radiated heat caused by the unequal expansion of the constituent crystals of the stone; for granite crystals the melting temperature is about 600 centigrade. Therefore the depth of roughening and ultimate flaking of the granite surface indicated the depth to which this temperature occurred and helped to determine the average ground temperatures in the instant following the explosion. This effect was noted for distances about 1 1/2 times as great in Nagasaki as in Hiroshima.
The second remarkable effect was the bubbling of roof tile. The size of the bubbles and their extent was proportional to their nearness to the center of explosion and also depended on how squarely the tile itself was faced toward the explosion. The distance ratio of this effect between Nagasaki and Hiroshima was about the same as for the flaking of polished granite.

Various other effects of the radiated heat were noted, including the lightening of asphalt road surfaces in spots which had not been protected from the radiated heat by any object such as that of a person walking along the road. Various other surfaces were discolored in different ways by the radiated heat.
As has already been mentioned the fact that radiant heat traveled only in straight lines from the center of explosion enabled observers to determine the direction toward the center of explosion from a number of different points, by observing the "shadows" which were cast by intervening objects where they shielded the otherwise exposed surface of some object. Thus the center of explosion was located with considerable accuracy. In a number of cases these "shadows" also gave an indication of the height of burst of the bomb and occasionally a distinct penumbra was found which enabled observers to calculate the diameter of the ball of fire at the instant it was exerting the maximum charring or burning effect.

One more interesting feature connected with heat radiation was the charring of fabric to different degrees depending upon the color of the fabric. A number of instances were recorded in which persons wearing clothing of various colors received burns greatly varying in degree, the degree of burn depending upon the color of the fabric over the skin in question. For example a shirt of alternate light and dark gray stripes, each about 1/8 of an inch wide, had the dark stripes completely burned out but the light stripes were undamaged; and a piece of Japanese paper exposed nearly 1 1/2 miles from X had the characters which were written in black ink neatly burned out.

CHARACTERISTICS OF THE INJURIES TO PERSONS

Injuries to persons resulting from the atomic explosions were of the following types:

A. Burns, from
1. Flash radiation of heat
2. Fires started by the explosions.
B. Mechanical injuries from collapse of buildings, flying debris, etc.
C. Direct effects of the high blast pressure, i.e., straight compression.
D. Radiation injuries, from the instantaneous emission of gamma rays and neutrons.

It is impossible to assign exact percentages of casualties to each of the types of injury, because so many victims were injured by more than one effect of the explosions. However, it is certain that the greater part of the casualties resulted from burns and mechanical injures. Col. Warren, one of America's foremost radioligists, stated it is probable that 7 per cent or less of the deaths resulted primarily from radiation disease.

The greatest single factor influencing the occurrence of casualties was the distance of the person concerned from the center of explosion.

Estimates based on the study of a selected group of 900 patients indicated that total casualties occurred as far out as 14,000 feet at Nagasaki and 12,000 feet at Hiroshima.

Burns were suffered at a considerable greater distance from X than any other type of injury, and mechanical injuries farther out than radiation effects.

Medical findings show that no person was injured by radioactivity who was not exposed to the actual explosion of the bombs. No injuries resulted from persistent radioactivity of any sort.

BURNS

Two types of burns were observed. These are generally differentiated as flame or fire burn and so-called flash burn.

The early appearance of the flame burn as reported by the Japanese, and the later appearance as observed, was not unusual.

The flash burn presented several distinctive features. Marked redness of the affected skin areas appeared almost immediately, according to the Japanese, with progressive changes in the skin taking place over a period of a few hours. When seen after 50 days, the most distinctive feature of these burns was their sharp limitation to exposed skin areas facing the center of the explosion. For instance, a patient who had been walking in a direction at right angles to a line drawn between him and the explosion, and whose arms were swinging, might have burns only on the outside of the arm nearest the center and on the inside of the other arm.

Generally, any type of shielding protected the skin against flash burns, although burns through one, and very occasionally more, layers of clothing did occur in patients near the center. In such cases, it was not unusual to find burns through black but not through white clothing, on the same patient. Flash burns also tended to involve areas where the clothes were tightly drawn over the skin, such as at the elbows and shoulders.

The Japanese report the incidence of burns in patients surviving more than a few hours after the explosion, and seeking medical attention, as high as 95%. The total mortalities due to burns alone cannot be estimated with any degree of accuracy. As mentioned already, it is believed that the majority of all the deaths occurred immediately. Of these, the Japanese estimate that 75%, and most of the reports estimate that over 50%, of the deaths were due to burns.

In general, the incidence of burns was in direct proportion to the distance from X. However, certain irregularities in this relationship result in the medical studies because of variations in the amount of shielding from flash burn, and because of the lack of complete data on persons killed outright close to X.

The maximum distance from X at which flash burns were observed is of paramount interest. It has been estimated that patients with burns at Hiroshima were all less than 7,500 feet from the center of the explosion at the time of the bombing. At Nagasaki, patients with burns were observed out to the remarkable distance of 13,800 feet.

MECHANICAL INJURIES

The mechanical injuries included fractures, lacerations, contusions, abrasions, and other effects to be expected from falling roofs, crumbling walls, flying debris and glass, and other indirect blast effects. The appearance of these various types of mechanical injuries was not remarkable to the medical authorities who studied them.

It was estimated that patients with lacerations at Hiroshima were less than 10,600 feet from X, whereas at Nagasaki they extended as far as 12,200 feet.

The tremendous drag of wind, even as far as 1 mile from X, must have resulted in many injuries and deaths. Some large pieces of a prison wall, for example, were flung 80 feet, and many have gone 30 feet high before falling. The same fate must have befallen many persons, and the chances of a human being surviving such treatment are probably small.

BLAST INJURIES

No estimate of the number of deaths or early symptoms due to blast pressure can be made. The pressures developed on the ground under the explosions were not sufficient to kill more than those people very near the center of damage (within a few hundred feet at most). Very few cases of ruptured ear drums were noted, and it is the general feeling of the medical authorities that the direct blast effects were not great. Many of the Japanese reports, which are believed to be false, describe immediate effects such as ruptured abdomens with protruding intestines and protruding eyes, but no such results were actually traced to the effect of air pressure alone.

RADIATION INJURIES

As pointed out in another section of this report the radiations from the nuclear explosions which caused injuries to persons were primarily those experienced within the first second after the explosion; a few may have occurred later, but all occurred in the first minute. The other two general types of radiation, viz., radiation from scattered fission products and induced radioactivity from objects near the center of explosion, were definitely proved not to have caused any casualties.

The proper designation of radiation injuries is somewhat difficult. Probably the two most direct designations are radiation injury and gamma ray injury. The former term is not entirely suitable in that it does not define the type of radiation as ionizing and allows possible confusion with other types of radiation (e.g., infra-red). The objection to the latter term is that it limits the ionizing radiation to gamma rays, which were undoubtedly the most important; but the possible contribution of neutron and even beta rays to the biological effects cannot be entirely ignored. Radiation injury has the advantage of custom, since it is generally understood in medicine to refer to X-ray effect as distinguished from the effects of actinic radiation. Accordingly, radiation injury is used in this report to mean injury due only to ionizing radiation.

According to Japanese observations, the early symptons in patients suffering from radiation injury closely resembled the symptons observed in patients receiving intensive roentgen therapy, as well as those observed in experimental animals receiving large doses of X-rays. The important symptoms reported by the Japanese and observed by American authorities were epilation (lose of hair), petechiae (bleeding into the skin), and other hemorrhagic manifestations, oropharyngeal lesions (inflammation of the mouth and throat), vomiting, diarrhea, and fever.

Epilation was one of the most spectacular and obvious findings. The appearance of the epilated patient was typical. The crown was involved more than the sides, and in many instances the resemblance to a monk's tonsure was striking. In extreme cases the hair was totally lost. In some cases, re-growth of hair had begun by the time patients were seen 50 days after the bombing. Curiously, epilation of hair other than that of the scalp was extremely unusual.

Petechiae and other hemorrhagic manifestations were striking findings. Bleeding began usually from the gums and in the more seriously affected was soon evident from every possible source. Petechiae appeared on the limbs and on pressure points. Large ecchymoses (hemorrhages under the skin) developed about needle punctures, and wounds partially healed broke down and bled freely. Retinal hemorrhages occurred in many of the patients. The bleeding time and the coagulation time were prolonged. The platelets (coagulation of the blood) were characteristically reduced in numbers.
Nausea and vomiting appearing within a few hours after the explosion was reported frequently by the Japanese. This usually had subsided by the following morning, although occasionally it continued for two or three days. Vomiting was not infrequently reported and observed during the course of the later symptoms, although at these times it generally appeared to be related to other manifestation of systemic reactions associated with infection.

Diarrhea of varying degrees of severity was reported and observed. In the more severe cases, it was frequently bloody. For reasons which are not yet clear, the diarrhea in some cases was very persistent.
Lesions of the gums, and the oral mucous membrane, and the throat were observed. The affected areas became deep red, then violacious in color; and in many instances ulcerations and necrosis (breakdown of tissue) followed. Blood counts done and recorded by the Japanese, as well as counts done by the Manhattan Engineer District Group, on such patients regularly showed leucopenia (low-white blood cell count). In extreme cases the white blood cell count was below 1,000 (normal count is around 7,000). In association with the leucopenia and the oropharyngeal lesions, a variety of other infective processes were seen. Wounds and burns which were healing adequately suppurated and serious necrosis occurred. At the same time, similar ulcerations were observed in the larynx, bowels, and in females, the gentalia. Fever usually accompanied these lesions.

Eye injuries produced by the atomic bombings in both cities were the subject of special investigations. The usual types of mechanical injuries were seen. In addition, lesions consisting of retinal hemorrhage and exudation were observed and 75% of the patients showing them had other signs of radiation injury.

The progress of radiation disease of various degrees of severity is shown in the following table:

Summary of Radiation Injury

Clinical Symptoms and Findings

Day after Explosion	Most Severe	Moderately Severe	Mild
1.	1. Nausea and vomiting	1. Nausea and vomiting
2.	after 1-2 hours.	after 1-2 hours.
3.	NO DEFINITE SYMPTOMS
4.
5.	2. Diarrhea
6.	3. Vomiting	NO DEFINITE SYMPTOMS
7.	4. Inflammation of the mouth and throat
8.	5. Fever
9.	6. Rapid emaciation
10.	Death		NO DEFINITE SYMPTOMS
11.	(Mortality probably100%)	2. Beginning epilation.
12.
13.
14.
15.
16.
17.
18.		3. Loss of appetite
19.		and general malaise.	1. Epilation
20.		4. Fever.	2. Loss of appetite
21.		5. Severe inflammation	and malaise.
22.		of the mouth and throat	3. Sore throat.
23.			4. Pallor.
24.			5. Petechiae
25.			6. Diarrhea
26.			7. Moderate emaciation.
27.		6. Pallor.
28.		7. Petechiae, diarrhea
29.		and nose bleeds	(Recovery unless com-
30.			plicated by previous
31.		8. Rapid emaciation	poor health or
		Death	super-imposed in-
		(Mortality probably 50%)	juries or infections).

It was concluded that persons exposed to the bombs at the time of detonation did show effects from ionizing radiation and that some of these patients, otherwise uninjured, died. Deaths from radiation began about a week after exposure and reached a peak in 3 to 4 weeks. They practically ceased to occur after 7 to 8 weeks.

Treatment of the burns and other physical injuries was carried out by the Japanese by orthodox methods. Treatment of radiation effects by them included general supportative measures such as rest and high vitamin and caloric diets. Liver and calcium preparations were administered by injection and blood transfusions were used to combat hemorrhage. Special vitamin preparations and other special drugs used in the treatment of similar medical conditions were used by American Army Medical Corps officers after their arrival. Although the general measures instituted were of some benefit no definite effect of any of the specific measures on the course of the disease could be demonstrated. The use of sulfonamide drugs by the Japanese and particularly of penicillin by the American physicians after their arrival undoubtedly helped control the infections and they appear to be the single important type of treatment which may have effectively altered the earlier course of these patients.

One of the most important tasks assigned to the mission which investigated the effects of the bombing was that of determining if the radiation effects were all due to the instantaneous discharges at the time of the explosion, or if people were being harmed in addition from persistent radioactivity.

This question was investigated from two points of view. Direct measurements of persistent radioactivity were made at the time of the investigation. From these measurements, calculations were made of the graded radiation dosages, i.e., the total amount of radiation which could have been absorbed by any person. These calculations showed that the highest dosage which would have been received from persistent radioactivity at Hiroshima was between 6 and 25 roentgens of gamma radiation; the highest in the Nagasaki Area was between 30 and 110 roentgens of gamma radiation.

The latter figure does not refer to the city itself, but to a localized area in the Nishiyama District. In interpreting these findings it must be understood that to get these dosages, one would have had to remain at the point of highest radioactivity for 6 weeks continuously, from the first hour after the bombing. It is apparent therefore that insofar as could be determined at Hiroshima and Nagasaki, the residual radiation alone could not have been detrimental to the health of persons entering and living in the bombed areas after the explosion.

The second approach to this question was to determine if any persons not in the city at the time of the explosion, but coming in immediately afterwards exhibited any symptoms or findings which might have been due to persistence induced radioactivity. By the time of the arrival of the Manhattan Engineer District group, several Japanese studies had been done on such persons. None of the persons examined in any of these studies showed any symptoms which could be attributed to radiation, and their actual blood cell counts were consistently within the normal range. Throughout the period of the Manhattan Engineer District investigation, Japanese doctors and patients were repeatedly requested to bring to them any patients who they thought might be examples of persons harmed from persistent radioactivity. No such subjects were found.

It was concluded therefore as a result of these findings and lack of findings, that although a measurable quantity of induced radioactivity was found, it had not been sufficient to cause any harm to persons living in the two cities after the bombings.

SHIELDING FROM RADIATION

Exact figures on the thicknesses of various substances to provide complete or partial protection from the effects of radiation in relation to the distance from the center of explosion, cannot be released at this time. Studies of collected data are still under way. It can be stated, however, that at a reasonable distance, say about 1/2 mile from the center of explosion, protection to persons from radiation injury can be afforded by a layer of concrete or other material whose thickness does not preclude reasonable construction.

Radiation ultimately caused the death of the few persons not killed by other effects and who were fully exposed to the bombs up to a distance of about 1/2 mile from X. The British Mission has estimated that people in the open had a 50% chance of surviving the effects of radiation at 3/4 of a mile from X.

EFFECTS OF THE ATOMIC BOMBINGS ON THE INHABITANTS OF THE BOMBED CITIES

In both Hiroshima and Nagasaki the tremendous scale of the disaster largely destroyed the cities as entities. Even the worst of all other previous bombing attacks on Germany and Japan, such as the incendiary raids on Hamburg in 1943 and on Tokyo in 1945, were not comparable to the paralyzing effect of the atomic bombs. In addition to the huge number of persons who were killed or injuried so that their services in rehabilitation were not available, a panic flight of the population took place from both cities immediately following the atomic explosions. No significant reconstruction or repair work was accomplished because of the slow return of the population; at the end of November 1945 each of the cities had only about 140,000 people. Although the ending of the war almost immediately after the atomic bombings removed much of the incentive of the Japanese people toward immediate reconstruction of their losses, their paralysis was still remarkable. Even the clearance of wreckage and the burning of the many bodies trapped in it were not well organized some weeks after the bombings. As the British Mission has stated, "the impression which both cities make is of having sunk, in an instant and without a struggle, to the most primitive level."

Aside from physical injury and damage, the most significant effect of the atomic bombs was the sheer terror which it struck into the peoples of the bombed cities. This terror, resulting in immediate hysterical activity and flight from the cities, had one especially pronounced effect: persons who had become accustomed to mass air raids had grown to pay little heed to single planes or small groups of planes, but after the atomic bombings the appearance of a single plane caused more terror and disruption of normal life than the appearance of many hundreds of planes had ever been able to cause before. The effect of this terrible fear of the potential danger from even a single enemy plane on the lives of the peoples of the world in the event of any future war can easily be conjectured.

The atomic bomb did not alone win the war against Japan, but it most certainly ended it, saving the thousands of Allied lives that would have been lost in any combat invasion of Japan.

EYEWITNESS ACCOUNT

Hiroshima -- August 6th, 1945

by Father John A. Siemes, professor of modern philosphy at Tokyo's Catholic University
Up to August 6th, occasional bombs, which did no great damage, had fallen on Hiroshima. Many cities roundabout, one after the other, were destroyed, but Hiroshima itself remained protected. There were almost daily observation planes over the city but none of them dropped a bomb. The citizens wondered why they alone had remained undisturbed for so long a time. There were fantastic rumors that the enemy had something special in mind for this city, but no one dreamed that the end would come in such a fashion as on the morning of August 6th.

August 6th began in a bright, clear, summer morning. About seven o'clock, there was an air raid alarm which we had heard almost every day and a few planes appeared over the city. No one paid any attention and at about eight o'clock, the all-clear was sounded. I am sitting in my room at the Novitiate of the Society of Jesus in Nagatsuke; during the past half year, the philosophical and theological section of our Mission had been evacuated to this place from Tokyo. The Novitiate is situated approximately two kilometers from Hiroshima, half-way up the sides of a broad valley which stretches from the town at sea level into this mountainous hinterland, and through which courses a river. From my window, I have a wonderful view down the valley to the edge of the city.

Suddenly--the time is approximately 8:14--the whole valley is filled by a garish light which resembles the magnesium light used in photography, and I am conscious of a wave of heat. I jump to the window to find out the cause of this remarkable phenomenon, but I see nothing more than that brilliant yellow light. As I make for the door, it doesn't occur to me that the light might have something to do with enemy planes. On the way from the window, I hear a moderately loud explosion which seems to come from a distance and, at the same time, the windows are broken in with a loud crash. There has been an interval of perhaps ten seconds since the flash of light. I am sprayed by fragments of glass. The entire window frame has been forced into the room. I realize now that a bomb has burst and I am under the impression that it exploded directly over our house or in the immediate vicinity.

I am bleeding from cuts about the hands and head. I attempt to get out of the door. It has been forced outwards by the air pressure and has become jammed. I force an opening in the door by means of repeated blows with my hands and feet and come to a broad hallway from which open the various rooms. Everything is in a state of confusion. All windows are broken and all the doors are forced inwards. The bookshelves in the hallway have tumbled down. I do not note a second explosion and the fliers seem to have gone on. Most of my colleagues have been injured by fragments of glass. A few are bleeding but none has been seriously injured. All of us have been fortunate since it is now apparent that the wall of my room opposite the window has been lacerated by long fragments of glass.

We proceed to the front of the house to see where the bomb has landed. There is no evidence, however, of a bomb crater; but the southeast section of the house is very severely damaged. Not a door nor a window remains. The blast of air had penetrated the entire house from the southeast, but the house still stands. It is constructed in a Japanese style with a wooden framework, but has been greatly strengthened by the labor of our Brother Gropper as is frequently done in Japanese homes. Only along the front of the chapel which adjoins the house, three supports have given way (it has been made in the manner of Japanese temple, entirely out of wood.)

Down in the valley, perhaps one kilometer toward the city from us, several peasant homes are on fire and the woods on the opposite side of the valley are aflame. A few of us go over to help control the flames. While we are attempting to put things in order, a storm comes up and it begins to rain. Over the city, clouds of smoke are rising and I hear a few slight explosions. I come to the conclusion that an incendiary bomb with an especially strong explosive action has gone off down in the valley. A few of us saw three planes at great altitude over the city at the time of the explosion. I, myself, saw no aircraft whatsoever.

Perhaps a half-hour after the explosion, a procession of people begins to stream up the valley from the city. The crowd thickens continuously. A few come up the road to our house. We give them first aid and bring them into the chapel, which we have in the meantime cleaned and cleared of wreckage, and put them to rest on the straw mats which constitute the floor of Japanese houses. A few display horrible wounds of the extremities and back. The small quantity of fat which we possessed during this time of war was soon used up in the care of the burns. Father Rektor who, before taking holy orders, had studied medicine, ministers to the injured, but our bandages and drugs are soon gone. We must be content with cleansing the wounds.

More and more of the injured come to us. The least injured drag the more seriously wounded. There are wounded soldiers, and mothers carrying burned children in their arms. From the houses of the farmers in the valley comes word: "Our houses are full of wounded and dying. Can you help, at least by taking the worst cases?" The wounded come from the sections at the edge of the city. They saw the bright light, their houses collapsed and buried the inmates in their rooms. Those that were in the open suffered instantaneous burns, particularly on the lightly clothed or unclothed parts of the body. Numerous fires sprang up which soon consumed the entire district. We now conclude that the epicenter of the explosion was at the edge of the city near the Jokogawa Station, three kilometers away from us. We are concerned about Father Kopp who that same morning, went to hold Mass at the Sisters of the Poor, who have a home for children at the edge of the city. He had not returned as yet.

Toward noon, our large chapel and library are filled with the seriously injured. The procession of refugees from the city continues. Finally, about one o'clock, Father Kopp returns, together with the Sisters. Their house and the entire district where they live has burned to the ground. Father Kopp is bleeding about the head and neck, and he has a large burn on the right palm. He was standing in front of the nunnery ready to go home. All of a sudden, he became aware of the light, felt the wave of heat and a large blister formed on his hand. The windows were torn out by the blast. He thought that the bomb had fallen in his immediate vicinity. The nunnery, also a wooden structure made by our Brother Gropper, still remained but soon it is noted that the house is as good as lost because the fire, which had begun at many points in the neighborhood, sweeps closer and closer, and water is not available. There is still time to rescue certain things from the house and to bury them in an open spot. Then the house is swept by flame, and they fight their way back to us along the shore of the river and through the burning streets.

Soon comes news that the entire city has been destroyed by the explosion and that it is on fire. What became of Father Superior and the three other Fathers who were at the center of the city at the Central Mission and Parish House? We had up to this time not given them a thought because we did not believe that the effects of the bomb encompassed the entire city. Also, we did not want to go into town except under pressure of dire necessity, because we thought that the population was greatly perturbed and that it might take revenge on any foreigners which they might consider spiteful onlookers of their misfortune, or even spies.

Father Stolte and Father Erlinghagen go down to the road which is still full of refugees and bring in the seriously injured who have sunken by the wayside, to the temporary aid station at the village school. There iodine is applied to the wounds but they are left uncleansed. Neither ointments nor other therapeutic agents are available. Those that have been brought in are laid on the floor and no one can give them any further care. What could one do when all means are lacking? Under those circumstances, it is almost useless to bring them in. Among the passersby, there are many who are uninjured. In a purposeless, insensate manner, distraught by the magnitude of the disaster most of them rush by and none conceives the thought of organizing help on his own initiative. They are concerned only with the welfare of their own families. It became clear to us during these days that the Japanese displayed little initiative, preparedness, and organizational skill in preparation for catastrophes. They failed to carry out any rescue work when something could have been saved by a cooperative effort, and fatalistically let the catastrophe take its course. When we urged them to take part in the rescue work, they did everything willingly, but on their own initiative they did very little.
At about four o'clock in the afternoon, a theology student and two kindergarten children, who lived at the Parish House and adjoining buildings which had burned down, came in and said that Father Superior LaSalle and Father Schiffer had been seriously injured and that they had taken refuge in Asano Park on the river bank. It is obvious that we must bring them in since they are too weak to come here on foot.

Hurriedly, we get together two stretchers and seven of us rush toward the city. Father Rektor comes along with food and medicine. The closer we get to the city, the greater is the evidence of destruction and the more difficult it is to make our way. The houses at the edge of the city are all severely damaged. Many have collapsed or burned down. Further in, almost all of the dwellings have been damaged by fire. Where the city stood, there is a gigantic burned-out scar. We make our way along the street on the river bank among the burning and smoking ruins. Twice we are forced into the river itself by the heat and smoke at the level of the street.

Frightfully burned people beckon to us. Along the way, there are many dead and dying. On the Misasi Bridge, which leads into the inner city we are met by a long procession of soldiers who have suffered burns. They drag themselves along with the help of staves or are carried by their less severely injured comrades...an endless procession of the unfortunate.

Abandoned on the bridge, there stand with sunken heads a number of horses with large burns on their flanks. On the far side, the cement structure of the local hospital is the only building that remains standing. Its interior, however, has been burned out. It acts as a landmark to guide us on our way.
Finally we reach the entrance of the park. A large proportion of the populace has taken refuge there, but even the trees of the park are on fire in several places. Paths and bridges are blocked by the trunks of fallen trees and are almost impassable. We are told that a high wind, which may well have resulted from the heat of the burning city, has uprooted the large trees. It is now quite dark. Only the fires, which are still raging in some places at a distance, give out a little light.

At the far corner of the park, on the river bank itself, we at last come upon our colleagues. Father Schiffer is on the ground pale as a ghost. He has a deep incised wound behind the ear and has lost so much blood that we are concerned about his chances for survival. The Father Superior has suffered a deep wound of the lower leg. Father Cieslik and Father Kleinsorge have minor injuries but are completely exhausted.

While they are eating the food that we have brought along, they tell us of their experiences. They were in their rooms at the Parish House--it was a quarter after eight, exactly the time when we had heard the explosion in Nagatsuke--when came the intense light and immediately thereafter the sound of breaking windows, walls and furniture. They were showered with glass splinters and fragments of wreckage. Father Schiffer was buried beneath a portion of a wall and suffered a severe head injury.
The Father Superior received most of the splinters in his back and lower extremity from which he bled copiously. Everything was thrown about in the rooms themselves, but the wooden framework of the house remained intact. The solidity of the structure which was the work of Brother Gropper again shone forth.

They had the same impression that we had in Nagatsuke: that the bomb had burst in their immediate vicinity. The Church, school, and all buildings in the immediate vicinity collapsed at once. Beneath the ruins of the school, the children cried for help. They were freed with great effort. Several others were also rescued from the ruins of nearby dwellings. Even the Father Superior and Father Schiffer despite their wounds, rendered aid to others and lost a great deal of blood in the process.

In the meantime, fires which had begun some distance away are raging even closer, so that it becomes obvious that everything would soon burn down. Several objects are rescued from the Parish House and were buried in a clearing in front of the Church, but certain valuables and necessities which had been kept ready in case of fire could not be found on account of the confusion which had been wrought. It is high time to flee, since the oncoming flames leave almost no way open. Fukai, the secretary of the Mission, is completely out of his mind. He does not want to leave the house and explains that he does not want to survive the destruction of his fatherland. He is completely uninjured. Father Kleinsorge drags him out of the house on his back and he is forcefully carried away.

Beneath the wreckage of the houses along the way, many have been trapped and they scream to be rescued from the oncoming flames. They must be left to their fate. The way to the place in the city to which one desires to flee is no longer open and one must make for Asano Park. Fukai does not want to go further and remains behind. He has not been heard from since. In the park, we take refuge on the bank of the river. A very violent whirlwind now begins to uproot large trees, and lifts them high into the air. As it reaches the water, a waterspout forms which is approximately 100 meters high. The violence of the storm luckily passes us by. Some distance away, however, where numerous refugees have taken shelter, many are blown into the river. Almost all who are in the vicinity have been injured and have lost relatives who have been pinned under the wreckage or who have been lost sight of during the flight. There is no help for the wounded and some die. No one pays any attention to a dead man lying nearby.

The transportation of our own wounded is difficult. It is not possible to dress their wounds properly in the darkness, and they bleed again upon slight motion. As we carry them on the shaky litters in the dark over fallen trees of the park, they suffer unbearable pain as the result of the movement, and lose dangerously large quantities of blood. Our rescuing angel in this difficult situation is a Japanese Protestant pastor. He has brought up a boat and offers to take our wounded up stream to a place where progress is easier. First, we lower the litter containing Father Schiffer into the boat and two of us accompany him. We plan to bring the boat back for the Father Superior. The boat returns about one-half hour later and the pastor requests that several of us help in the rescue of two children whom he had seen in the river. We rescue them. They have severe burns. Soon they suffer chills and die in the park.

The Father Superior is conveyed in the boat in the same manner as Father Schiffer. The theology student and myself accompany him. Father Cieslik considers himself strong enough to make his way on foot to Nagatsuke with the rest of us, but Father Kleinsorge cannot walk so far and we leave him behind and promise to come for him and the housekeeper tomorrow. From the other side of the stream comes the whinny of horses who are threatened by the fire. We land on a sand spit which juts out from the shore. It is full of wounded who have taken refuge there. They scream for aid for they are afraid of drowning as the river may rise with the sea, and cover the sand spit. They themselves are too weak to move. However, we must press on and finally we reach the spot where the group containing Father Schiffer is waiting.

Here a rescue party had brought a large case of fresh rice cakes but there is no one to distribute them to the numerous wounded that lie all about. We distribute them to those that are nearby and also help ourselves. The wounded call for water and we come to the aid of a few. Cries for help are heard from a distance, but we cannot approach the ruins from which they come. A group of soldiers comes along the road and their officer notices that we speak a strange language. He at once draws his sword, screamingly demands who we are and threatens to cut us down. Father Laures, Jr., seizes his arm and explains that we are German. We finally quiet him down. He thought that we might well be Americans who had parachuted down. Rumors of parachutists were being bandied about the city. The Father Superior who was clothed only in a shirt and trousers, complains of feeling freezing cold, despite the warm summer night and the heat of the burning city. The one man among us who possesses a coat gives it to him and, in addition, I give him my own shirt. To me, it seems more comfortable to be without a shirt in the heat.

In the meantime, it has become midnight. Since there are not enough of us to man both litters with four strong bearers, we determine to remove Father Schiffer first to the outskirts of the city. From there, another group of bearers is to take over to Nagatsuke; the others are to turn back in order to rescue the Father Superior. I am one of the bearers. The theology student goes in front to warn us of the numerous wires, beams and fragments of ruins which block the way and which are impossible to see in the dark. Despite all precautions, our progress is stumbling and our feet get tangled in the wire. Father Kruer falls and carries the litter with him. Father Schiffer becomes half unconscious from the fall and vomits. We pass an injured man who sits all alone among the hot ruins and whom I had seen previously on the way down.

On the Misasa Bridge, we meet Father Tappe and Father Luhmer, who have come to meet us from Nagatsuke. They had dug a family out of the ruins of their collapsed house some fifty meters off the road. The father of the family was already dead. They had dragged out two girls and placed them by the side of the road. Their mother was still trapped under some beams. They had planned to complete the rescue and then to press on to meet us. At the outskirts of the city, we put down the litter and leave two men to wait until those who are to come from Nagatsuke appear. The rest of us turn back to fetch the Father Superior.

Most of the ruins have now burned down. The darkness kindly hides the many forms that lie on the ground. Only occasionally in our quick progress do we hear calls for help. One of us remarks that the remarkable burned smell reminds him of incinerated corpses. The upright, squatting form which we had passed by previously is still there.

Transportation on the litter, which has been constructed out of boards, must be very painful to the Father Superior, whose entire back is full of fragments of glass. In a narrow passage at the edge of town, a car forces us to the edge of the road. The litter bearers on the left side fall into a two meter deep ditch which they could not see in the darkness. Father Superior hides his pain with a dry joke, but the litter which is now no longer in one piece cannot be carried further. We decide to wait until Kinjo can bring a hand cart from Nagatsuke. He soon comes back with one that he has requisitioned from a collapsed house. We place Father Superior on the cart and wheel him the rest of the way, avoiding as much as possible the deeper pits in the road.

About half past four in the morning, we finally arrive at the Novitiate. Our rescue expedition had taken almost twelve hours. Normally, one could go back and forth to the city in two hours. Our two wounded were now, for the first time, properly dressed. I get two hours sleep on the floor; some one else has taken my own bed. Then I read a Mass in gratiarum actionem, it is the 7th of August, the anniversary of the foundation of our society. Then we bestir ourselves to bring Father Kleinsorge and other acquaintances out of the city.

We take off again with the hand cart. The bright day now reveals the frightful picture which last night's darkness had partly concealed. Where the city stood everything, as far as the eye could reach, is a waste of ashes and ruin. Only several skeletons of buildings completely burned out in the interior remain. The banks of the river are covered with dead and wounded, and the rising waters have here and there covered some of the corpses. On the broad street in the Hakushima district, naked burned cadavers are particularly numerous. Among them are the wounded who are still alive. A few have crawled under the burnt-out autos and trams. Frightfully injured forms beckon to us and then collapse. An old woman and a girl whom she is pulling along with her fall down at our feet. We place them on our cart and wheel them to the hospital at whose entrance a dressing station has been set up. Here the wounded lie on the hard floor, row on row. Only the largest wounds are dressed. We convey another soldier and an old woman to the place but we cannot move everybody who lies exposed in the sun. It would be endless and it is questionable whether those whom we can drag to the dressing station can come out alive, because even here nothing really effective can be done. Later, we ascertain that the wounded lay for days in the burnt-out hallways of the hospital and there they died.

We must proceed to our goal in the park and are forced to leave the wounded to their fate. We make our way to the place where our church stood to dig up those few belongings that we had buried yesterday. We find them intact. Everything else has been completely burned. In the ruins, we find a few molten remnants of holy vessels. At the park, we load the housekeeper and a mother with her two children on the cart. Father Kleinsorge feels strong enough, with the aid of Brother Nobuhara, to make his way home on foot. The way back takes us once again past the dead and wounded in Hakushima. Again no rescue parties are in evidence. At the Misasa Bridge, there still lies the family which the Fathers Tappe and Luhmer had yesterday rescued from the ruins. A piece of tin had been placed over them to shield them from the sun. We cannot take them along for our cart is full. We give them and those nearby water to drink and decide to rescue them later. At three o'clock in the afternoon, we are back in Nagatsuka.

After we have had a few swallows and a little food, Fathers Stolte, Luhmer, Erlinghagen and myself, take off once again to bring in the family. Father Kleinsorge requests that we also rescue two children who had lost their mother and who had lain near him in the park. On the way, we were greeted by strangers who had noted that we were on a mission of mercy and who praised our efforts. We now met groups of individuals who were carrying the wounded about on litters. As we arrived at the Misasa Bridge, the family that had been there was gone. They might well have been borne away in the meantime. There was a group of soldiers at work taking away those that had been sacrificed yesterday.

More than thirty hours had gone by until the first official rescue party had appeared on the scene. We find both children and take them out of the park: a six-year old boy who was uninjured, and a twelve-year old girl who had been burned about the head, hands and legs, and who had lain for thirty hours without care in the park. The left side of her face and the left eye were completely covered with blood and pus, so that we thought that she had lost the eye. When the wound was later washed, we noted that the eye was intact and that the lids had just become stuck together. On the way home, we took another group of three refugees with us. They first wanted to know, however, of what nationality we were. They, too, feared that we might be Americans who had parachuted in. When we arrived in Nagatsuka, it had just become dark.

We took under our care fifty refugees who had lost everything. The majority of them were wounded and not a few had dangerous burns. Father Rektor treated the wounds as well as he could with the few medicaments that we could, with effort, gather up. He had to confine himself in general to cleansing the wounds of purulent material. Even those with the smaller burns are very weak and all suffered from diarrhea. In the farm houses in the vicinity, almost everywhere, there are also wounded. Father Rektor made daily rounds and acted in the capacity of a painstaking physician and was a great Samaritan. Our work was, in the eyes of the people, a greater boost for Christianity than all our work during the preceding long years.

Three of the severely burned in our house died within the next few days. Suddenly the pulse and respirations ceased. It is certainly a sign of our good care that so few died. In the official aid stations and hospitals, a good third or half of those that had been brought in died. They lay about there almost without care, and a very high percentage succumbed. Everything was lacking: doctors, assistants, dressings, drugs, etc. In an aid station at a school at a nearby village, a group of soldiers for several days did nothing except to bring in and cremate the dead behind the school.

During the next few days, funeral processions passed our house from morning to night, bringing the deceased to a small valley nearby. There, in six places, the dead were burned. People brought their own wood and themselves did the cremation. Father Luhmer and Father Laures found a dead man in a nearby house who had already become bloated and who emitted a frightful odor. They brought him to this valley and incinerated him themselves. Even late at night, the little valley was lit up by the funeral pyres.

We made systematic efforts to trace our acquaintances and the families of the refugees whom we had sheltered. Frequently, after the passage of several weeks, some one was found in a distant village or hospital but of many there was no news, and these were apparently dead. We were lucky to discover the mother of the two children whom we had found in the park and who had been given up for dead. After three weeks, she saw her children once again. In the great joy of the reunion were mingled the tears for those whom we shall not see again.

The magnitude of the disaster that befell Hiroshima on August 6th was only slowly pieced together in my mind. I lived through the catastrophe and saw it only in flashes, which only gradually were merged to give me a total picture. What actually happened simultaneously in the city as a whole is as follows: As a result of the explosion of the bomb at 8:15, almost the entire city was destroyed at a single blow. Only small outlying districts in the southern and eastern parts of the town escaped complete destruction. The bomb exploded over the center of the city. As a result of the blast, the small Japanese houses in a diameter of five kilometers, which compressed 99% of the city, collapsed or were blown up. Those who were in the houses were buried in the ruins. Those who were in the open sustained burns resulting from contact with the substance or rays emitted by the bomb. Where the substance struck in quantity, fires sprang up. These spread rapidly.

The heat which rose from the center created a whirlwind which was effective in spreading fire throughout the whole city. Those who had been caught beneath the ruins and who could not be freed rapidly, and those who had been caught by the flames, became casualties. As much as six kilometers from the center of the explosion, all houses were damaged and many collapsed and caught fire. Even fifteen kilometers away, windows were broken. It was rumored that the enemy fliers had spread an explosive and incendiary material over the city and then had created the explosion and ignition. A few maintained that they saw the planes drop a parachute which had carried something that exploded at a height of 1,000 meters. The newspapers called the bomb an "atomic bomb" and noted that the force of the blast had resulted from the explosion of uranium atoms, and that gamma rays had been sent out as a result of this, but no one knew anything for certain concerning the nature of the bomb.

How many people were a sacrifice to this bomb? Those who had lived through the catastrophe placed the number of dead at at least 100,000. Hiroshima had a population of 400,000. Official statistics place the number who had died at 70,000 up to September 1st, not counting the missing ... and 130,000 wounded, among them 43,500 severely wounded. Estimates made by ourselves on the basis of groups known to us show that the number of 100,000 dead is not too high. Near us there are two barracks, in each of which forty Korean workers lived. On the day of the explosion, they were laboring on the streets of Hiroshima. Four returned alive to one barracks and sixteen to the other. 600 students of the Protestant girls' school worked in a factory, from which only thirty to forty returned.

Most of the peasant families in the neighborhood lost one or more of their members who had worked at factories in the city. Our next door neighbor, Tamura, lost two children and himself suffered a large wound since, as it happened, he had been in the city on that day. The family of our reader suffered two dead, father and son; thus a family of five members suffered at least two losses, counting only the dead and severely wounded. There died the Mayor, the President of the central Japan district, the Commander of the city, a Korean prince who had been stationed in Hiroshima in the capacity of an officer, and many other high ranking officers. Of the professors of the University, thirty-two were killed or severely injured. Especially hard hit were the soldiers. The Pioneer Regiment was almost entirely wiped out. The barracks were near the center of the explosion.

Thousands of wounded who died later could doubtless have been rescued had they received proper treatment and care, but rescue work in a catastrophe of this magnitude had not been envisioned; since the whole city had been knocked out at a blow, everything which had been prepared for emergency work was lost, and no preparation had been made for rescue work in the outlying districts. Many of the wounded also died because they had been weakened by under-nourishment and consequently lacked in strength to recover. Those who had their normal strength and who received good care slowly healed the burns which had been occasioned by the bomb. There were also cases, however, whose prognosis seemed good who died suddenly. There were also some who had only small external wounds who died within a week or later, after an inflammation of the pharynx and oral cavity had taken place. We thought at first that this was the result of inhalation of the substance of the bomb. Later, a commission established the thesis that gamma rays had been given out at the time of the explosion, following which the internal organs had been injured in a manner resembling that consequent upon Roentgen irradiation. This produces a diminution in the numbers of the white corpuscles.

Only several cases are known to me personally where individuals who did not have external burns later died. Father Kleinsorge and Father Cieslik, who were near the center of the explosion, but who did not suffer burns became quite weak some fourteen days after the explosion. Up to this time small incised wounds had healed normally, but thereafter the wounds which were still unhealed became worse and are to date (in September) still incompletely healed. The attending physician diagnosed it as leucopania. There thus seems to be some truth in the statement that the radiation had some effect on the blood. I am of the opinion, however, that their generally undernourished and weakened condition was partly responsible for these findings. It was noised about that the ruins of the city emitted deadly rays and that workers who went there to aid in the clearing died, and that the central district would be uninhabitable for some time to come. I have my doubts as to whether such talk is true and myself and others who worked in the ruined area for some hours shortly after the explosion suffered no such ill effects.

None of us in those days heard a single outburst against the Americans on the part of the Japanese, nor was there any evidence of a vengeful spirit. The Japanese suffered this terrible blow as part of the fortunes of war ... something to be borne without complaint. During this, war, I have noted relatively little hatred toward the allies on the part of the people themselves, although the press has taken occasion to stir up such feelings. After the victories at the beginning of the war, the enemy was rather looked down upon, but when allied offensive gathered momentum and especially after the advent of the majestic B-29's, the technical skill of America became an object of wonder and admiration.

The following anecdote indicates the spirit of the Japanese: A few days after the atomic bombing, the secretary of the University came to us asserting that the Japanese were ready to destroy San Francisco by means of an equally effective bomb. It is dubious that he himself believed what he told us. He merely wanted to impress upon us foreigners that the Japanese were capable of similar discoveries. In his nationalistic pride, he talked himself into believing this. The Japanese also intimated that the principle of the new bomb was a Japanese discovery. It was only lack of raw materials, they said, which prevented its construction. In the meantime, the Germans were said to have carried the discovery to a further stage and were about to initiate such bombing. The Americans were reputed to have learned the secret from the Germans, and they had then brought the bomb to a stage of industrial completion.

We have discussed among ourselves the ethics of the use of the bomb. Some consider it in the same category as poison gas and were against its use on a civil population. Others were of the view that in total war, as carried on in Japan, there was no difference between civilians and soldiers, and that the bomb itself was an effective force tending to end the bloodshed, warning Japan to surrender and thus to avoid total destruction. It seems logical to me that he who supports total war in principle cannot complain of war against civilians. The crux of the matter is whether total war in its present form is justifiable, even when it serves a just purpose. Does it not have material and spiritual evil as its consequences which far exceed whatever good that might result? When will our moralists give us a clear answer to this question?

Figure 1

Contents

●　Trinity Atomic Test Site
●　Hiroshima and Nagasaki
●　Nuclear Weapon Physics and Technology
●　Effects of Nuclear Weapons and Nuclear War
●　The Years of Atmospheric Testing
●　Gallery of Test Photos
●　Civil Defense
●　Criticality and Radiation Accidents
●　Los Alamos Publications (no longer) Online
●　Other Online Sources
●　Annotated Bibliography

Related Links

Alsos Digital Library for Nuclear Issues

● Hiroshima
● Nagasaki

Atomicarchive.com

● Hiroshima Photographs
● Nagasaki Photographs
● Documents on the bombing of Hiroshima and Nagasaki

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Copyright © 1995-2003 Gregory Walker (trinatomic at earthlink dot net), Creator of Trinity Atomic Web Site.

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