Fukushima reactor readings raise reheating concern

[malaise]

http://www.guardian.co.uk/world/2012/feb/12/fukushima-reactor-reheating-concern
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The plant's operator, Tokyo Electric Power (Tepco), said the temperature inside No 2 reactor – one of three that suffered meltdown after last year's earthquake and tsunami – may have reached 82C on Sunday.

Tepco said there was no evidence that the melted fuel inside had reached criticality. The utility reportedly increased the amount of cooling water being injected into the reactor along with a boric acid solution, which is used to prevent the fuel from undergoing sustained nuclear reactions.

Confirmation that the temperature has risen above 80C could force the government to reverse its declaration two months ago that the crippled plant was in a safe state known as cold shutdown.

Cold shutdown is achieved when the temperature inside the reactors remains below 100C and there is a significant reduction in radiation leaks. Given that Tepco assumes a margin of error of 20C, the actual temperature could have risen to 102C.

Plant workers are unable to take accurate readings of the temperature inside the damaged reactor because radiation levels are still too high for them to enter and examine the state of the melted fuel, which is thought to be resting at the bottom of the reactor's pressure vessel.