The No. 3 reactor of the Mihama Nuclear Power Station in Mihama, Fukui Prefecture, is pictured in this photo taken from a Mainichi Shimbun helicopter on Nov. 12, 2016.
Another operation approval of aging nuclear reactor contradicts 40-year rule
The Nuclear Regulation Authority (NRA) has allowed Kansai Electric Power Co. to continue running the No. 3 reactor at its Mihama Nuclear Power Station in Fukui Prefecture beyond the 40-year limit.
This is the third nuclear reactor in the country that will have been allowed to continue to operate beyond the 40-year limit — following the No. 1 and 2 reactors at the Takahama plant also in Fukui Prefecture.
The move contradicts rules stipulating that nuclear reactors should be decommissioned after being operated for 40 years, in principle.
It had been viewed as extremely difficult to extend the lifespan of Mihama’s No. 3 reactor because of its old design and difficulties in improving the reactor’s quake resistance as the plant operator is required to largely increase the estimate of the scale of the maximum earthquake that could hit the plant.
As such, the NRA once hinted that it would discontinue examinations of the reactor to see if it meets the new regulatory standards.
However, Kansai Electric Power spent 165 billion yen on measures to enhance the safety of the reactor. The NRA increased its personnel to accelerate the examination of the plant, and managed to approve the continuation of its operation by the deadline.
Six aging nuclear reactors across the country are set to be shut down and decommissioned. Their operators voluntarily decided to decommission these reactors, whose outputs are small, considering the units’ cost-benefit performance.
However, if power companies apply for permission to extend the lifespan of nuclear reactors, the NRA will almost certainly grant permission.
The rules limiting the operation of a nuclear reactor to 40 years, in principle, was established with the aim of reducing Japan’s reliance on atomic power stations following the outbreak of the Fukushima nuclear crisis in March 2011. Both the NRA and power companies should go back to the fundamentals of the rules.
Operation extension approved for Mihama reactor
Japan’s nuclear regulator has said an aging reactor will be allowed to operate beyond its 40-year maximum life span.
The No.3 reactor at the Mihama nuclear power plant, on the Sea of Japan coast, has been given a 20-year extension. The Nuclear Regulation Authority made the unanimous decision on Wednesday.
The reactor, in Fukui Prefecture, went offline in March 2011 for a regular checkup and has not been restarted.
The Mihama reactor turns 40 years old later this year, and it will now be permitted to run until November 2036.
The Nuclear Regulation Authority heard evidence on Wednesday that the reactor’s pipes and electric cables are expected to meet required standards for up to 60 years since operations began in 1976.
Some members referred to a 2004 accident at the reactor in which 5 workers were killed after high-temperature steam leaked from a damaged pipe. They urged the operator, Kansai Electric Power Company, to keep checking for possible decay to the facility.
The reactor is the third in Japan to be granted an extension, after 2 reactors at the nearby Takahama plant were approved for restarts in June.
Kansai Electric said it will not restart operations until additional safety work has been completed, by March 2020 at the earliest. It said it believes the restart will be economically practical.