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From Far Labs, a Vivid Picture Emerges of Japan Crisis  NYT/IHT

For the clearest picture of what is happening at Japan's Fukushima Daiichi nuclear power plant, talk to scientists thousands of miles away. Thanks to the unfamiliar but sophisticated art of atomic forensics, experts around the world have been able to document the situation vividly. Over decades, they have become very good at illuminating the hidden workings of nuclear power plants from afar, turning scraps of information into detailed analyses.


Most of these computer-based forensics systems were developed after the 1979 partial meltdown at Three Mile Island, when regulators found they were essentially blind to what was happening in the reactor. Since then, to satisfy regulators, companies that run nuclear power plants use snippets of information coming out of a plant to develop simulations of what is happening inside and to perform a variety of risk evaluations.

Indeed, the detailed assessments of the Japanese reactors that Energy Secretary Steven Chu gave on Friday -- when he told reporters that about 70 percent of the core of one reactor had been damaged, and that another reactor had undergone a 33 percent meltdown -- came from forensic modeling.

The bits of information that drive these analyses range from the simple to the complex. They can include everything from the length of time a reactor core lacked cooling water to the subtleties of the gases and radioactive particles being emitted from the plant. Engineers feed the data points into computer simulations that churn out detailed portraits of the imperceptible, including many specifics on the melting of the hot fuel cores.

"It is not necessary to have hope in order to persevere."
by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Sat Apr 2nd, 2011 at 10:48:39 PM EST
Tellurium 129 Presence Is Proof Of Inadvertent Recriticality At Fukushima

For those wondering just why TEPCO and Japan in general have been in such as scramble to cover up as much of the reactor in a concrete sarcophagus, after up until now the utility had been perfectly happy to come up with one after another useless idea of delaying the inevitable moment of sarcophagation, here is Arnie Gunderson from Fairewinds and Associates explaining that now there is definitive proof, courtesy of Tellurium 129 and a order of magnitude higher concentration of Iodine 131 in Reactor 1, that the reactor is now undergoing sporadic events of recriticality: in other words, the fission reaction is recommencing on its own, and without any supervision, emitting undetectable neutron beams which are irradiating any and all personnel still on location. For the time being these recritical events are isolated, although courtesy of the whole premise behind a nuclear power plant, all it takes is for some form of critical threshold to be reached, and for a full blown self-sustaining chain reaction to result in Chernobyl part 2. If nothing else, we now know why the authorities are desperate to bury everything literally under the sand. Because at least a few thousands tons of concrete will provide a modest buffer for unprecedented amount of radiation before these hit the surrounding environment. Lastly, all those hoping that natural rod cooling is sufficient, and if the plant is left along long enough on its own, things will get better, are now proven wrong.
by das monde on Mon Apr 4th, 2011 at 03:28:47 AM EST
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by das monde on Mon Apr 4th, 2011 at 07:31:11 AM EST
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