Sunday, February 12, 2012

Fukushima No. 2 reactor temperature up to 82C, but not critical: TEPCO

TOKYO (Kyodo) -- Tokyo Electric Power Co. said Sunday the temperature at the bottom of the No. 2 reactor at its crippled Fukushima No. 1 nuclear plant rose further to 82 C, but the reactor has not gone critical.

While the thermometer reading at shortly after 2 p.m. marked a new high since the reactor attained a cold shutdown in December, the utility known as TEPCO said it has confirmed that sustained nuclear reactions are not taking place in the reactor as no radioactive xenon has been detected inside its containment vessel.

TEPCO reported the latest development immediately to the Nuclear and Industrial Safety Agency of the Economy, Trade and Industry Ministry as the temperature exceeded the limit of 80 C designated by the company's safety regulation for maintaining a cold shutdown, it said.

It is considered desirable to keep the temperature below 80 C, while the bottom of a reactor pressure vessel must be kept below 100 C in a stable cold shutdown, in view of the margin of error of thermometers, according to TEPCO officials.

TEPCO plans to increase the amount of water injected as a coolant by 3 tons per hour and pour 1 ton of boric acid later Sunday to prevent any event of criticality. Read More