Unit 3 at Kansai Electric Power Co's Mihama NPP in Japan’s Fukui Prefecture passed a key safety assessment on 5 October with a view to going back on line, and continuing operation beyond its 40-year design life. In the wake of the Fukushima accident the Nuclear Regulation Authority (NRA) introduced new regulations limiting reactor operations to 40 years in principle. Mihama 3 is the third reactor seeking to continue in service beyond the 40-year limit to pass the screening. The other two are units 1 and 2 at the utility's Takahama NPP, also in Fukui.
Mihama 3 went offline in May 2011 for a regular check-up and has not been restarted since pending inspections by NRA. Before the reactor can restart, it will require further permission from the Nuclear Regulation Authority on details of equipment design and other issues by the end of November, when it reaches the 40 year milestone. Missing the deadline would require Kansai to close the reactor. Even if the deadline is met, the reactor is not expected to restart before spring 2020 to allow time to complete all the required safety measures.
Kansai Electric plans to spend about JPY165bn ($1.6 bn) to upgrade the facilities to meet the new regulations, which reflect the lessons learned from the Fukushima Daiichi disaster. Although operation for an additional 20 years is possible, nuclear regulators initially indicated that it would be extremely difficult to win approval for an extension. Some utilities have decided to scrap their ageing reactors in face of the expense of upgrading. Kansai Electric has given up on restarting the Mihama 1 and 2.
Meanwhile, Kyushu Electric Power Company took unit 1 of the Sendai NPP in Kagoshima prefecture offline on 4 October for a scheduled three-month refuelling and maintenance outage. The company will also examine the unit's reactor vessel, containment building and the plant's used fuel storage facility, as requested by prefectural governor Satoshi Mitazono. Sendai 2 is expected to enter a similar outage on 16 December. Only one other reactor is currently in operation in Japan - Shikoku Electric Power Company's Ikata 3 in Ehime prefecture. Chugoku Electric Power Company in July filed an application with NRA for approval of its plan to decommission unit 1 at its Shimane NPP in Shimane prefecture. Two other reactors have been designated by their operators for decommissioning: Tsuruga-1 and Genkai-1.