The Nuclear Regulation Authority (NRA) has concluded that Hokkaido Electric Power’s Tomari Unit 3 is not located on an active fault line. It also found the proposed safety measures sufficient to withstand earthquakes and tsunamis, in principle approving the nuclear power plant’s restart. The decision follows the reactor’s selection in Japan’s second long-term decarbonization auction earlier this week.
Following a public comments period, the draft safety review document is expected to be officially approved this summer. Hokkaido EPCO is aiming to return the 912MW unit to commercial operation “as soon as possible in 2027.”
Prior to the restart, the company will need to build a new seawall. Additionally, a lawsuit filed by local residents opposing the power plant that led to an injunction against its operations in 2022 must be resolved. Similar cases related to Ikata and Sendai power plants were dismissed by their respective district courts earlier this year.
Tomari Nuclear Power Plant was shut down in May 2012 after the 2011 Fukushima nuclear disaster. Hokkaido EPCO applied for Unit 3’s safety review in July 2013. Its approval has taken longer than that for Kansai Electric Power’s Takahama Units 3 and 4 and Kyushu Electric Power’s Sendai Units 1 and 2, which applied around the same time and restarted commercial operations between 2015 and 2017.
“This was a prime example of a nuclear power plant where natural disaster-related review was extremely difficult,” said NRA’s Chairman Shinsuke Yamanaka at a press conference after the meeting according to The Nikkei.
Unit 3’s restart is expected to play a key role in meeting increased data center- and semiconductor manufacturing-related power demand in Hokkaido in the late 2020s. According to the group’s “2035 Management Vision,” the company is eyeing early 2030s restart for the 579MW Units 1 and 2.
Should Tomari 3’s restart proceed as planned, it will become the 15th unit to come online post-Fukushima. The most recent reactor to return to commercial operation was Onagawa 2, which did so in late 2024.
Correction (May 9, 2025): The previous version of this article incorrectly indicated that Hokkaido EPCO applied for safety review in June 2013 and that it was eyeing late 2030s restart for Units 1 and 2.
