NRA head frowns on ministry’s N-plant management ideas

The Yomiuri Shimbun
The Mihama nuclear power plant is seen in Fukui Prefecture on Oct. 26.

Nuclear Regulation Authority Chairman Shinsuke Yamanaka expressed reservations about a proposal by the Economy, Trade and Industry Ministry to set the maximum operational period of nuclear power plants beyond the current upper limit of 60 years.

Currently, the operating period of a nuclear power plant is legally set at 40 years in principle, extendable to a maximum of 60 years, but the ministry is aiming to raise that ceiling.

On Tuesday, the ministry presented a panel of experts with three proposals: maintaining the current regulations; setting no upper limit on the operating period; setting a certain limit but not counting periods when the plant is shut down toward the total operating period.

The last option “would make it very difficult to design” safety regulations, Yamanaka said at a press conference on Wednesday.

“It is important for safety regulations to look at the status of nuclear power plants on a calendar year basis [without excluding offline periods],” Yamanaka said.

He placed importance on the rule under which nuclear power plants are subject to regulations from the time when they become operational. Among the reasons for this stance, he said that concrete used in plant buildings and other related structures deteriorates over time, even when the plants are not in operation.

Envisioning nuclear power plants being allowed to operate for more than 60 years, the NRA is looking into a proposal to check the safety of plants no less frequently than every 10 years after 30 years of operation.