[ RadSafe ] Claim from Tokyo Professor that Fukushima is worse than Hiroshima

georgestanford1 at comcast.net georgestanford1 at comcast.net
Fri Aug 19 11:40:58 CDT 2011


Comparisons of "radiation released" are meaningless. There's a widespread misconception that the radioactive fallout from Hiroshima had a major impact on local health, but it did not. The radioactive material from the Hiroshima bomb affected probably nobody at all, the reason being that the explosion was an "air burst," as they say in the trade -- an explosion whose fireball did not touch the ground. The damage at Hiroshima was caused by blast, fire, and the one-time burst of gamma and neutron radiation. There was virtually no local fallout. All the radioactive fission products were vaporized and carried upward in the mushroom cloud, to spread around the world in the upper atmosphere. When eventually they came back down as "global fallout," they were so dilute that nobody's dose was significantly increased over background. 

To produce local fallout, you have to have a "ground burst," which vaporizes a lot of extra material that gets incorporated in the mushroom cloud and soon condenses, contaminated with fission products. The heavy, now-radioactive particles soon fall back down, creating a radioactive environment. That did not happen at Hiroshima. 

There was no mushroom cloud from Fukushima, of course, so whatever radioactivity was released stayed close to the ground, with some of it deposited locally. It's irrelevant that the number of curies of radiation in the damaged Fukushima reactors was undoubtedly much greater than in the Hiroshima bomb's fission products. How much of it left the plant, I wouldn't know. 

-- George Stanford 
Reactor physicist, retired 

For replies, please use 
<gstanford at aya.yale.edu>. 

----- Original Message -----
From: "Roger Helbig" <rwhelbig at gmail.com> 
To: radsafe at health.phys.iit.edu 
Sent: Friday, August 19, 2011 6:31:46 AM 
Subject: [ RadSafe ] Claim from Tokyo Professor that Fukushima is worse than Hiroshima 

The following put out by the ultra-left Citizens for Legitimate Government 
sounds preposterous - does anyone know anything about the background of the 
professor who is making these claims - anytime that they make claims of 
equivalence to Hiroshima or Nagasaki, I have strong doubts about the 
veracity, but the anti-nukes just lap it up especially since this is being 
voiced so near the anniversary of the two atomic bombings that ended WW-II. 

Roger Helbig 

*Fukushima radiation released equal to more than 29 'Hiroshima-type atomic 
Aug 2011 "How much radioactive materials have been released from the 
[Daiichi nuclear] plant?" asked Dr Tatsuhiko Kodama, a professor at the 
Research Centre for Advanced Science and Technology and Director of the 
University of Tokyo's Radioisotope Centre, in a July 27 speech to the 
Committee of Health, Labour and Welfare at Japan's House of Representatives. 
Kodama's centre, using 27 facilities to measure radiation across the 
country, has been closely monitoring the situation at Fukushima - and their 
findings are alarming. According to Dr Kodama, the total amount of radiation 
released over a period of more than five months from the ongoing Fukushima 
nuclear disaster is the equivalent to more than 29 "Hiroshima-type atomic 
bombs" and the amount of uranium released "is equivalent to 20" Hiroshima 
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