Having the workers run past the super-hot 10-plus sieverts/hr exhaust stack and hurry up the 2nd floor with 5-plus sieverts/hr radiation, TEPCO has managed to install a heat exchanger for the Spent Fuel Pool of Reactor 1 to cool the pool steadily.
One of the workers who installed the heat exchanger there tweeted that he got 10 milisieverts of radiation exposure for the several days of work.
No one knows how hot the pool has been anyway because the instrument is broken since the earthquake on March 11, but TEPCO says the heat exchanger will cool the water to the same level as the water in Reactors 2, 3, and 4.
It's called "keishiki" in Japanese. In English, it's "formality". Cooling the reactors that are likely devoid of melted fuel and injecting nitrogen gas, and cooling the SFP without knowing how hot it is are all part of the "formality" or checklist that TEPCO submit to the government, so the government can support its claim of safety and stability of the situation at Fukushima and tell the residents to go home.
From Yomiuri Shinbun (11:43PM JST 8/10/2011):
TEPCO started the heat exchanger for the Spent Fuel Pool in Reactor 1 on August 10 morning to cool the water in the SFP steadily.
The heat exchangers for the SFPs in Reactors 2, 3 and 4 are already operational. Steady cooling of the SFP is scheduled to be accomplished in January 2012 in the "roadmap", but TEPCO will succeed in achieving that goal much earlier [if the Reactor 1 SFP heat exchanger works as planned].
According to TEPCO, there are 392 fuel rod clusters in the Reactor 1 SFP. The temperature of the water hasn't been measured because the instrument is broken, but the water has been injected on a regular basis. TEPCO doesn't think the temperature is very high, and with the heat exchanger it will be brought down to 30 to 40 degrees Celsius, the same level as that of Reactors 2, 3 and 4.
On the side note, Goshi Hosono, PM Kan's assistant and the minister in charge of investigating the Fukushima nuclear accident, will also be in charge of the new organization to support electric power companies to pay damages in nuclear accidents. The law to create the organization passed both Houses in the Diet. Conflict of interest, Mr. Hosono?