Tokyo: Tokyo Electric Power Company said that the temperature of the crippled No 3 nuclear reactor at the Fukushima Daiichi atomic power plant has fallen below 100 C, signaling progress toward the plant's cold shutdown.
This is the first time that the temperature measured at the bottom of the No 3 reactor pressure vessel dropped below 100 C since the nuclear crisis began at the complex in March due to a devastating earthquake and tsunami. The No 1 reactor is already below 90 C.
The plant operator known as TEPCO said on Monday using an additional cooling method of showering water to the reactor core is likely to have helped lower the temperature of the No 3 reactor pressure vessel.
TEPCO is considering applying the same method to the No 2 reactor.
The utility has said the Nos 1 to 3 reactors' cores are assumed to have suffered meltdowns and the melted fuel is believed to be solidified at the bottom of the pressure vessels.
Cooling the pressure vessels of the plant's damaged Nos 1 to 3 reactors is part of the key conditions to realize the plant's cold shutdown, which the government and TEPCO hopes to achieve by January at the latest.
The cold shutdown is also defined by the government and TEPCO as a state in which the release of radioactive materials from reactors is under control and radiation exposure dose is significantly held down.