Update: Radiation levels continue to be extremely high at the doomed nuclear plant. It is now confirmed that workers at the site have been exposed to 2-6 Sv or 200-600 rems/hr. A report of 100rems/hr in Unit 2 was made by technicians but TEPCo later said the report was an error. As previously reported, TEPCo has been understating the scope of the disaster at Fukushima.
Mitsuhiko Tanaka, a nuclear engineer who helped design Unit 4, held a press conference with Citizens Nuclear Information Center in Tokyo on Saturday night. He said that based on his analysis of events, Unit 1 suffered a loss of coolant accident within hours of the earthquake. Most probably a coolant pipe was ruptured by the magnitude 9 earthquake. Loss of electrical power did not allow emergency cooling systems to prevent melting of the reactor core. Thus, TEPCo knew within hours of the earthquake that a core meltdown of some magnitude was very likely. TEPCo has repeatedly stated that it designed the plant to withstand a 100 year event. However a "black swan" event similar to what happened on March 11th was already in the record books going back to the 9th Century AD. Power to the cooling systems for all four damaged reactors has not yet been restored two weeks after the quake and attendant tsunamis, despite optimistic reports from the plant's owner. Meanwhile levels of radiation continue to be emitted. The sea near the plant is becoming contaminated, and radiation from Fukushima has been detected as far away as the eastern coast of the United States.
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| Tsunamis approach plant March 11th |
{25.3.11}TEPCo has finally admitted, two weeks after the enormous earthquake and tsunamis killed thousands in northeastern Japan, there is a reactor breach at Unit 3 of the Fukushima-Daiichi power plant. Unit 3 is the only reactor at the plant that uses MOX or mixed oxides, a blend of fissionable material that includes plutonium produced by reprocessing weapons grade plutonium, as fuel. The delayed announcement is consistent with the restrictive flow of information coming from the disaster site. Based on
the level of fallout so far,
Greenpeace, the international environmental advocacy group, has rated the disaster a 7 on the scale of nuclear incidents wherein significant amounts of radioactivity are released into the atmosphere affecting populations in other countries. The 1986 Chernobyl meltdown of one reactor without a containment shield rained radiation over eastern and northern Europe, and is rated a 7 or the most severe incident. Japan's government, seeming to be in understandable denial at times, is rating Daiichi which is experiencing the melting of three reactors cores and overheating of spent fuel in a fourth, a 5 or comparable to The Three Mile Island partial meltdown in 1979. About half a single reactor core at Three Mile Island melted. Of course Japan's population density is much higher than either Pennsylvania's or Ukraine's, so more people will be exposed.
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| TEPCo Unit 3, March 23rd |
Unit 3 is said to be emitting 20rems/hr, about 10,000 times normal. However, three workers were treated for radiation burns Thursday after walking in contaminated water indicating radiation levels may be even higher. Isotopes not normally found in cooling water were detected (minor actinides such as yttrium91 and cesium136).
Radioactivity has been found in 11 different vegetables and water. Twenty-three Japanese legislators have urged a wider evacuation zone. The
radioactive plume from Daiichi has reached the west coast of the US where Californians are stocking up on iodine pills and kelp.
