Kansai Electric Power Co and Japan Atomic Power Co have submitted applications to Japan's Nuclear Regulation Authority (NRA) seeking approval for plans to begin dismantling three ageing nuclear reactors in Fukui Prefecture. These include units 1 and 2 at Kansai Electric's Mihama NPP - 340MWe and 500MWe pressurised water reactors, respectively, in operation since the early 1970s - and unit 1 at JAPC's Tsuruga plant, a 341MWe boiling water reactor that started up in 1970.
The plans outline the facilities and equipment to be dismantled and a timetable for completing the work.The dismantling operations are expected to take around 30 years for Mihama 1 and 2 and about 25 years for Tsuruga 1 reactor. All three were decommissioned in April last year.
JAPC said decommissioning of Tsuruga 1 will be undertaken in three stages. The first stage, taking about nine years, will involve preparing the reactor for dismantling (including the removal of all fuel), and the second (also nine years) will involved dismantling the reactor and other major equipment. The third stage (six years), will involve demolition of the reactor building. The operation is expected to generate some 20,600t of solid waste, including 40t of high-level waste, 1,990t of intermediate-level waste and 10,760t of low-level waste. The rest will not need to be treated as radioactive.
Independent studies of Tsuruga 1 completed in 2014 confirmed that geologic faults running under the site are inactive. However, JAPC said that while it would have been technically feasible to bring Tsuruga 1 up to the standards required, the work and cost made it uneconomic.
Both Kansai Electric and JAPC have concluded agreements with the Fukui Prefectural government and the governments of the host municipalities for economic improvements to the affected area.
Other reactors decommissioned last April include Kyushu Electric Power Co's Genkai plant in Saga Prefecture and unit 1 at Chugoku Electric Power Co's Shimane plant in Shimane Prefecture. Kyushu Electric filed an application in December for NRA approval of its schedule to scrap the Genkai 1.