Japan’s Nuclear Regulation Authority has formally approved a safety screening report affirming that unit 3 of Hokkaido Electric Power Company’s Tomari NPP meets its safety standards.
Tomari 3 is the first reactor to receive such approval since unit 2 reactor at Chugoku Electric Power Company’s Shimane NPP passed a safety screening in 2021. It is the 18th reactor to be approved since more stringent safety standards were adopted in the wake of the 2011 Fukushima disaster.
Tomari 3, the newest reactor in Japan, started operation in 2009. The authority screened the reactor for an unusually long period of 12 years while Hokkaido Electric detailed its measures to deal with possible earthquakes and tsunamis. However, the company is still in litigation with local residents and is appealing against a 2022 Sapporo District Court injunction ruling that the reactor failed to meet safety standards for tsunamis. It is uncertain whether the company can restart the reactor in 2027 as planned, given as it also needs to obtain agreements from local governments.
Hokkaido Electric applied for the safety screening on the day the current safety standards took effect, in July 2013. The company has increased the maximum seismic ground motion assumed in its quake resistance design from 550 gals to 693 gals and the assumed maximum tsunami height from 7.3 metres to 17.8 metres.
The company is building a seawall 19 metres high with plans to complete it by around March 2027. It has also presented plans to build a new port in the north of the plant and establish a new transportation route for nuclear fuel, in view of the possibility that a nuclear fuel transportation ship could collide with the seawall in the event of a tsunami.
Hokkaido Electric estimates that the reactor’s safety measures will cost at least JPY515bn ($3.47bn). It aims to restart the plant’s remaining two reactors in the first half of the 2030s.
