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Tohoku Electric considering decommissioning Onagawa nuke plant reactor

Tohoku Electric Power Co.'s Onagawa Nuclear Power Station is seen from a Mainichi Shimbun helicopter in Onagawa, Miyagi Prefecture, on March 11, 2011. (Mainichi/Koichiro Tezuka)

SENDAI -- Decommissioning the Onagawa Nuclear Power Station's No. 1 reactor is "being considered as an option," Tohoku Electric Power Co. President Hiroya Harada told a press conference on Sep. 27.

The announcement marked the first time that the power utility in northeastern Japan has mentioned dismantling a nuclear reactor. The two other reactors at the plant straddling the town of Onagawa and the city of Ishinomaki, Miyagi Prefecture, including the No. 2 reactor that is currently undergoing a Nuclear Regulation Authority (NRA) safety check, are being prepared to restart operations, Harada said.

The entire plant was originally shut down as the tsunami triggered by the March 2011 Great East Japan Earthquake flooded the basement of the building housing the No. 2 reactor.

The No. 1 reactor, with a maximum output of 524,000 kilowatts, began operation in June 1984. It is the oldest reactor among four belonging to Tohoku Electric that stopped after the 2011 earthquake, including one at the Higashidori Nuclear Power Station in the village of Higashidori, Aomori Prefecture, in northern Japan.

According to the utility company, all four reactors are boiling water reactors. The No. 1 unit is being considered for decommissioning because its older design makes it difficult to make safety upgrades -- such as earthquake resistant features -- that are proceeding for the No. 2 reactor.

The No. 1 reactor, in operation for almost 35 years, has been under review to determine whether its operational life will be extended or the unit will be decommissioned. The maximum period of operation for reactors is set at 40 years in principle following the triple core meltdowns at Tokyo Electric Power Co.'s Fukushima No. 1 Nuclear Power Station in March 2011. The facility lost electric power to run the cores' cooling systems when the generators were struck by the earthquake-triggered tsunami.

(Japanese original by Natsuki Hayakawa, Sendai Bureau)

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