NISA to let reactor run beyond 40 years


The Nuclear and Industrial Safety Agency plans to conclude that the Mihama nuclear power plant’s No. 2 reactor in Fukui Prefecture is safe enough to operate beyond 40 years, the period of operation that requires safety assessments, sources said Wednesday.

It would be the first time since the Fukushima disaster last year for NISA to give such permission to a reactor.

However, the fate of reactors designated as operable beyond 40 years will be reconsidered once a new nuclear regulatory body is launched to replace NISA as part of efforts to enhance nuclear regulations. The government has also submitted a bill to revise the law regulating reactors that would set a 40-year lifespan for reactors.

Under such circumstances, a decision by NISA to extend the life of the Mihama reactor could draw public criticism.

NISA was expected to present a draft report later in the day to a panel of experts discussing the issue, in which it was to say that Kansai Electric Power Co.’s safety evaluation on reactor 2 is appropriate.

Mihama Mayor Jiro Yamaguchi welcomed the expected move.

“It’s necessary to examine safety under the current system,” Yamaguchi told reporters.

“New standards (under the new regulatory body) will be stricter, but checks (anyway will need to) be conducted again,” the mayor said.

Although reactor 1 at the Fukushima No. 1 plant had been operating for almost 40 years when it was crippled last year, the agency has not urged utilities to take additional measures to deal with potential dangers connected with aging, saying it is not clear whether that was a factor in the crisis.

The Mihama reactor 2 started operating July 25, 1972. Two other reactors have been permitted to keep running for more than 40 years. They are reactor 1 at Japan Atomic Power Co.’s Tsuruga power station in Fukui Prefecture and reactor 1 at Kepco’s Mihama plant.

NISA conducted on-site inspections on Mihama’s reactor 2 in April and judged there is no problem in Kepco’s management and operation plan, the sources said.

Under the current rule, utilities need to assess the safety of reactors older than 30 years. NISA checks the evaluation and the utility is required to conduct safety assessments every 10 years after that.