Kansai amends Mihama decommissioning plans

13 February 2017

Kansai Electric Power Company has submitted an amendment to its decommissioning plan for the shut down units 1 and 2 of its Mihama nuclear power plant in Japan's Fukui Prefecture.

Mihama NPP 400 (NRA)
Mihama (Image: NRA)

Mihama 1 and 2 were among five reactors officially taken out of service in April 2015. Kansai submitted its decommissioning plans for the units to the Nuclear Regulation Authority (NRA) in February last year for approval. Its plans outline the facilities and equipment to be dismantled and a timetable for completing the work.

At that time, Kansai said it expected to take around 30 years to decommission Mihama 1 and 2. These are 340 MWe and 500 MWe pressurized water reactors (PWRs), respectively, that had been in operation since the early 1970s.

Kansai said on 10 February it had submitted an amendment to its plan. After feedback from the NRA on its original plan, the company has added sections confirming decommissioning works at Mihama 1 and 2 would not interfere with the safe operation of unit 3. In addition, used fuel stored at the site would not be damaged in the event of a loss of cooling water in the fuel storage pools, it said.

Last November, the NRA approved an extension to the operating period for Mihama unit 3, clearing the 780 MWe PWR to operate until 2036. Mihama 3 was the third Japanese unit to be granted a licence extension enabling it to operate beyond 40 years under revised regulations, following Kansai's Takahama 1 and 2, which received NRA approval last June.

Kansai said in March 2015 it had decided to decommission units 1 and 2, which together with Japan's other power reactors had been idled after the Fukushima Daiichi accident of 2011, rather than applying to restart them. Its decision followed an assessment of work needed to ensure the units meet requirements introduced by the NRA in July 2013. The other reactors to be retired were unit 1 of Japan Atomic Power Company's Tsuruga plant, Kyushu Electric's Genkai 1, and Chugoku Electric's Shimane 1.

Researched and written
by World Nuclear News