Fission Criticality In Cooling Ponds Threaten Explosion At Fukushima
The threat of a fission explosion at the Fukushima power facility emerged today when the roof of the number three reactor exploded and fears that a spent fuel pool, located over the reactor, has been compromised. The pool, designed to allow reactor fuel to cool off for several years, was constructed on top of the Fukushima reactors instead of underground. As of 2010, there were 3450 fuel assemblies in the pool at the number three reactor. The destruction of the number three reactor building has experts concerned about whether the spent fuel storage pool, which sits just below the roof, could have survived intact the hydrogen explosion. The explosion was much more severe than Saturday's blast at the number one reactor.
As massive amounts of seawater are pumped by fire trucks into Fukushima's failing nuclear reactors and cooling ponds, the radioactive waste water, now laden with a variety of radioisotopes, is being flushed into the sea.
Just how much danger the spent fuel pool raises is made clear in a November 2010 powerpoint presentation from the Tokyo Electric Company detailing how fuel storage works at the huge complex.
The fuel inventory in the pool is detailed on page 9. According to TEPCO, each reactor generates 700 "waste" fuel assemblies a year, and there are 3450 assemblies in each pool at the Fukushima Daiichi plant, plus another 6,291 in a common pool in a separate building.