The temperature in a reactor at the crippled Fukushima No. 1 nuclear plant may have risen to 82 degrees on Feb. 12, a situation that could force the government to revoke the declaration of “an equivalent of cold shutdown.”
The temperature in a reactor at the crippled Fukushima No. 1 nuclear plant may have risen to 82 degrees on Feb. 12, a situation that could force the government to revoke the declaration of “an equivalent of cold shutdown.”
If the temperature is confirmed to exceed 80 degrees, it will not meet the condition for the government’s definition of the state of a cold shutdown, which is below 100 degrees, due to the margin of error. The margin of error associated with the temperature is up to 20 degrees as it cannot be verified if the reading is accurate, according to Tokyo Electric Power Co., the plant operator.
The government declared late last year that the plant was brought under control, citing temperatures at the bottom of the three embattled reactors’ pressure vessels of less than 100 degrees and a significant reduction in the leakage of radioactive materials from the reactors. TEPCO said on Feb. 12 that it increased the injection of cooling water the day before following the rise in temperature.
The temperature at the bottom of the No. 2 reactor’s pressure vessel surged to 78 degrees earlier on Feb. 12. It was at 74.9 degrees at 11 p.m. on Feb. 11, according to TEPCO.
However, temperature levels measured by two other thermometers set at the same height in the reactor hovered at nearly 35 degrees.
TEPCO said that it does not know why the temperature is rising.
The company increased the flow of cooling water early on Feb. 7 after the temperature hit 73.3 degrees temporarily the day before.
Since then, readings have ranged from 64 degrees to 71 degrees.
High radiation levels in the No. 2 reactor are preventing workers from entering and examining the state of melted nuclear fuel.
The No. 2 reactor had a meltdown, like two other reactors at the plant, after the nuclear complex lost all power sources to cool the reactors in the wake of the March 11 quake and tsunami last year.