Tokyo Electric Power Co. and the government on Oct. 17 released a newly revised a road map to bring the stricken Fukushima No. 1 nuclear power plant under control. It shows that a "cold shutdown" of the Nos. 1, 2 and 3 reactors at the plant will be achieved by the end of the year. The reactor cores suffered meltdowns after the March 11 earthquake and tsunami inflicted severe damage, but the temperature in the lower part of the pressure vessels has now fallen below 100 C. As of Oct. 15, it was between 73 C. and 83 C.
The amount of radioactive substances released from the reactors has been halved from the level in September when the road map was earlier revised. It is estimated that the three reactors are now releasing radioactive substances at the rate of about 100 million becquerels per hour maximum, about one-eighth of a millionth the level immediately after the nuclear crisis started.
Tepco and the government said that with this rate, the annual exposure to radiation in the Fukushima No. 1 compound will be around 0.2 millisieverts maximum, lower than the goal of one millisievert. They also said that the level of contaminated water in the reactor building basements has stabilized. In view of those factors, Tepco and the government said in their newly revised road map that the "cold shutdown" will be achieved by the end of this year.