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Japan's nuclear regulation body mustn't be swayed by public

Publication Date : 12-12-2012


Japan's Nuclear Regulation Authority (NRA) has shown its determination to take a more painstaking approach to ensure the safety of nuclear power plants.

On Monday, the organisation's expert panel issued an opinion that concluded there was a high possibility a crush zone beneath a nuclear reactor of the Tsuruga power plant in Fukui Prefecture "is an active fault."

The Tsuruga power plant has two reactors, both of which are now idled due to periodic safety checks. "Under present conditions, I don't think we can start a safety review [of the reactors] in preparation for restarting operations," NRA Chairman Shunichi Tanaka said.

His remarks suggest the panel's opinion has made the reactivation of the reactors difficult, dealing Japan Atomic Power Co.--operator of the Tsuruga plant--a serious blow.

The panel's five members, including NRA Acting Chairman Kunihiko Shimazaki, were unanimous in issuing their opinion, which was issued after discussions on the geographic features of the crush zone and data from excavation surveys based on on-site inspections. The five members are experts in seismology or geology.

Restarting operations difficult

The government's safety guidelines prohibit the construction of nuclear power plants on active faults because a slippage may damage the safety equipment in reactor buildings.

The crush zone under examination runs directly beneath the Tsuruga nuclear power plant's No 2 reactor. Some panel members also voiced concern about an active fault that runs parallel to the two reactors. The existence of this fault has been known for some time.

Japan Atomic Power has no choice but to continue to suspend the Tsuruga plant's operations unless it can persuade the panel to reverse its decision by offering new data verifying the plant's safety. The utility may have to consider the option of decommissioning the nuclear power plant. The company must exercise extreme care before making a decision on whether to build two new reactors at the plant.

The now-defunct Nuclear and Industrial Safety Agency discussed the possible danger of the active fault beneath the Tsuruga plant for more than five years, but refrained from taking concrete action, such as suspending operations. The agency decided to conduct a thorough study of the possible active fault only after last year's Great East Japan Earthquake.

There is a theory that the earthquake changed the geological formation around the Japanese archipelago, making it more likely for earthquakes to occur. It has become even more important for nuclear power plants to take appropriate safety measures against earthquakes.

Similar judgements likely

The NRA decided to conduct independent, detailed studies of crush zones beneath six nuclear power plants to confirm whether they are active faults. Some surveys have already been carried out, such as at the Tsuruga plant and Kansai Electric Power Co.'s Oi nuclear power plant in Fukui Prefecture. We believe the NRA's decision to conduct the studies was fair enough. There is a possibility the organisation will continue to harshly evaluate the safety of power plants.

It is important for the NRA to make scientific judgements based on objective data.

In issuing its opinion on the Tsuruga power plant's crush zone, Shimazaki said, "We were able to reach a conclusion thanks to detailed studies conducted by Japan Atomic Power."

The NRA should continue to make strict decisions as in the Tsuruga plant case, without being influenced by current public sentiment calling for the abolition of all nuclear power plants.

If the Tsuruga plant remains idle, it will affect the nation's power supply, and deal a heavy blow to Japan Atomic Power, which specialises in nuclear energy. It is crucial for the government and the electric utility industry to take the initiative in dealing with the problem.


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