POSTED BY: Bill Sweet / Sat, March 12, 2011
In the disastrous accident unfolding at Japan's Fukushima Dai-ichi nuclear power plant, Unit 1, there so far have been two major incidents. The first was the failure of the backup power system meant to keep cooling systems running if the plant lost external power; it evidently was the result of damage to a turbine generator from the earthquake and tsunami. The second, a day later, was the explosion of the outer containment building, apparently the result of hydrogen buildup from several possible sources.
Following the explosion, emergency operators flooded the inner containment building with seawater to cool it and stop core melting, which may or may not--reports vary--have penetrated the reactor's steel vessel. Operators also are injecting boron into the reactor vessel to head off a re-criticality--a situation in which melting fuel reconfigures itself and starts reacting self-sustainably again. Meanwhile, with some radiation escaping the plant, the evacuation zone has been expanded to a 20-kilometer radius and authorities are preparing to pass out potassium iodide, which prevents radioactive iodine from concentrating in the thyroid gland and causing cancer.
Because of the explosion and the radiation leakage, Fukushima Dai-ichi already ranks as the second most serious nuclear power plant accident after Chernobyl. In terms of public impact, it may come in first because it's taking place in a country that has the world's most sophisticated earthquake prediction and mitigation systems, top-notch nuclear technology, and a pronounced national radiation phobia. Japan is not a technically backward country with notoriously poor reactor designs, the way the former Soviet Union was. Its nuclear power plants were designed and built with an acute consciousness of extreme earthquake dangers.
Read the whole story on: Energywise
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