Approving Life Extension of Nuclear Reactors

The Nuclear Regulation Authority (NRA) approved extending, from forty years to sixty years, life of the reactors #3 and #4 in Takahama Nuclear Power plant owned by Kansai Electric Power Company (KEPCO). This made the seventh and eighth examples that old reactors would extend their life beyond the limit legally determined. Regulation on nuclear power plant, which was established with a bitter lesson in the Great Northeastern Japan Earthquake.

It was Yoshihiko Noda administration that established a rule on length of reactors’ life as for forty years at the longest. The rule was added in the Reactors Regulation Act which was revised a year after the great earthquake, but it had an exception of extending the limit for twenty years. The exception was made with proposal by the bureaucrats. In a discussion over the bill in the Diet, Noda explained that the extension would be “extremely exceptional.”

 

After twelve years have passed, the exceptional rule was mutilated and extension of life of reactors in nuclear power plants became normal. NRA approved the extension of Takahama #1 and #2 for the first time in 2016. After that, the authority showed green light for Mihama #3, Tokai-daini #1 and Sendai #1 and #2. The authority has approved all the requests for extension by power companies.

 

Reactor #3 and #4 of Takahama started its operation 1985. KEPCO submitted NRA a request for extension in April 2023. NRA reconfirmed through its inspection that the main devices in the reactors had no problem and they were properly maintained. NRA defines its own role limitedly. “We assess whether they would fulfill the regulatory standard. I am not commenting on whether the extension would be exceptional or not,” said the NRA Chairman, Shinsuke Yamanaka. It is unclear whether Yamanaka recognizes that the extension can be “extremely exceptional.”

 

Takahama #3 and #4 uses mixed oxide nuclear fuel, which radiation is stronger than normal fuel, causing deterioration of metal used in pressure vessels of the reactors. Some damages, which were supposed to be made by rust on steel devices, have been found in a steam generator. KEPCO decided to replace those old devices. NRA concluded that those troubles had no problem to extend the life of those reactors.

 

Fumio Kishida administration changed the rule of extension last year. New rule allows nuclear reactors to include the period when they stopped their operation for counting their life length. If a reactor experienced five-year recess and was approved to extend its life to sixty years, it can live for sixty-five years as a total.

 

The major earthquake in Noto Peninsula earlier this year caused damages on electric transformer in Shika Nuclear Power Plant. If they had triggered a nuclear accident requiring evacuation, the residents would not have been able to move to anywhere, because Shika plant was located on the root of the peninsula. Tahakama plant has the same condition. NRA ruled out that kind of condition, because the authority believes that they were not responsible for evacuation of the residents.