Nuclear watchdog to urge shutdown of Oi plant if active fault found

December 28, 2012

By HISASHI HATTORI/ Senior Staff Writer

The Nuclear Regulation Authority said Dec. 27 it will recommend shutting down the Oi nuclear power plant in Fukui Prefecture if an active geological fault is found to run directly beneath the facility.

Shunichi Tanaka, NRA chairman, also told The Asahi Shimbun that the three-year timeline presented by the Abe administration is too short for safety screenings to be completed for all 50 nuclear reactors in Japan.

An NRA expert panel began a second session on Dec. 28 of on-site geological surveys at the Oi plant to decide whether a fault line cutting across its premises is active. Two reactors at the Oi plant are the only ones currently up and running in Japan.

Tanaka said he would use nonbinding "administrative discretion" measures to instruct Kansai Electric Power Co., operator of the Oi plant, to halt operations if the fault running beneath key equipment is found to be active.

The government's safety standards stipulate that no key component of a nuclear plant should be installed directly above an active fault.

The law on the regulation of nuclear reactors allows the issuance of a shutdown order in case of imminent danger.

However, Tanaka said it would be difficult to issue a legally binding shutdown order after the discovery of an active fault beneath an emergency water intake channel because that would be short of constituting "imminent danger."

He added that the Tsuruga nuclear power plant, also in Fukui Prefecture, will have to be decommissioned after an NRA expert panel found that an active fault likely runs directly beneath a nuclear reactor building.

Given the circumstances, he said safety screenings are impossible.

Tanaka acknowledged that a report has yet to be published and a formal conclusion has yet to be reached.

"We cannot enter safety screenings (that should precede a restart) if it is officially decided that (an active) fault runs directly beneath a nuclear reactor building," he said. "No power utility would want to hold on to an inoperable nuclear reactor forever."

Tanaka said it would be up to the discretion of Japan Atomic Power Co., the Tsuruga plant operator, to decide whether to decommission it.

The Abe administration, which formally took office on Dec. 26, said it plans to decide within three years whether operations can resume at each of Japan's 50 nuclear reactors. That means the NRA has to examine whether each one of those reactors meets stringent safety standards.

Tanaka said he did not believe the screening procedures could be completed within three years.

A written agreement presented Dec. 25 by the coalition government of Shinzo Abe's Liberal Democratic Party and New Komeito pledged to respect the decisions of the NRA.

"Restarts of nuclear reactors will depend on the NRA's decisions, based on expert knowledge, that places foremost priority on safety in line with international standards," the agreement read.

By HISASHI HATTORI/ Senior Staff Writer
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Shunichi Tanaka, chairman of the Nuclear Regulation Authority (Photo by Makoto Kaku)

Shunichi Tanaka, chairman of the Nuclear Regulation Authority (Photo by Makoto Kaku)

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  • Shunichi Tanaka, chairman of the Nuclear Regulation Authority (Photo by Makoto Kaku)
  • An NRA expert panel conducts a second session of on-site geological surveys at the Oi plant in Fukui Prefecture on Dec. 28. (Kenta Sujino)

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