Friday, Nov. 4, 2011
Find out true reactor conditions
Tokyo Electric Power Co. announced Wednesday that there is the possibility that criticality, a sustained nuclear chain reaction, had occurred “temporarily” and “locally” in the No. 2 reactor of the stricken Fukushima No. 1 nuclear power plant. It detected radioactive xenon-133 and xenon-135, products of uranium or plutonium fission, in gases collected Tuesday from the reactor.
Because the half life of xenon-133 is 5.25 days and that of xeon-135 is 9.14 hours, criticality is very likely to have occurred just before the gases were analyzed.
Although more than seven months have passed since the start of the nuclear fiasco, clearly the reactor has not yet been stabilized. Tepco’s plan to achieve “cold shutdown” of the Nos. 1, 2 and 3 reactors by the end of this year may face difficulty.