Installation of multiplex power distribution systems

April 25, 2013

TEPCO shuts down cooling system for spent nuclear fuel pool at Fukushima plant

http://mainichi.jp/english/english/newsselect/news/20130425p2a00m0na011000c.html 

Tokyo Electric Power Co. (TEPCO) said it temporarily shut down the cooling system for a spent nuclear fuel pool of the No. 3 reactor at the Fukushima No. 1 Nuclear Power Plant at 9:39 a.m. on April 25 to install a multiplex power distribution system there.

TEPCO, the operator of the crippled Fukushima nuclear power station, said the cooling system was expected to remain shut for about 33 hours. While the cooling system is offline, the temperature of the water in the spent nuclear fuel pool is likely to rise about five degrees Celsius. But TEPCO said, "There is no problem. The water temperature was low enough at 16 degrees when it was shut down." The utility also said it would shut down the cooling system for the spent nuclear fuel pool at the No. 4 reactor for about nine hours on April 26 in order to conduct similar installation work.

In March this year, a power outage, triggered by a rat that touched a switchboard and caused a short circuit, disabled cooling systems for the spent fuel pools of the No. 1, 3 and 4 reactors. It took nearly 30 hours for the cooling systems to be fully recovered. The Nuclear Regulation Authority instructed TEPCO to take preventative measures promptly, including installing multiplex power distribution systems, among other measures.