Regulator agrees Japan's Tomari 3 meets safety requirements

Wednesday, 30 April 2025

The Tomari plant comprises two 550 MWe pressurised water reactors (PWRs) (units 1 and 2) and a 912 MWe PWR (unit 3). All three units have been offline since unit 3 stopped power generation for regular inspection in 2012. Operator Hokkaido Electric Power Company is seeking regulatory approval to restart all three reactors.

Hokkaido EPC applied for a review in July 2013 to assess whether its plan for upgrades at Tomari 3 satisfies updated safety standards introduced following the March 2011 accident at the Fukushima Daiichi plant.

The company built a new 16.5-metre-high seawall to protect the plant from tsunamis, but later agreed to build one 19 metres in height, based on the regulator's advice. Construction of the seawall is currently under way and expected to be completed in early 2027. Hokkaido EPC has also upgraded its quake-resistant design for the facilities to cope with more intense acceleration of seismic waves - from up to 550 gals to 693 gals. 

At a regular meeting of the Nuclear Regulation Authority (NRA) on 30 April, a draft of the review document that shows the reactor meets the new regulatory safety standards was unanimously approved by its five members. It marks the first regulatory approval for a reactor restart since 2021.

The report is expected to be formally adopted by the NRA in the coming months, following a period for public comments. Assuming formal adoption of the report, Tomari 3 will become the 18th Japanese reactor to pass the regulator's safety screenings.

"To be honest, it took more than 11 years of time to evaluate the faults on the site due to a lack of specialised knowledge," Hokkaido EPC President Susumu Saito was quoted as saying by NHK. "I think that the review, which is a prerequisite for restarting the plant, is nearing completion, but the next steps, such as approval of the construction plan and safety regulations and pre-use inspections, remain to be completed." 

The company will still need to obtain the consent of local governments before it can restart Tomari 3.

Hokkaido Governor Naomichi Suzuki said: "I think the review has reached the final stage, but as the review is still ongoing with public comments and other matters to come, it is not the time to make any preconceived statements. When specific details are presented, we would like to respond appropriately based on discussions in the prefectural assembly, etc," NHK reported. Regarding municipalities that are subject to local consent, he said, "There are various opinions regarding the scope of local consent for restarting, but it is necessary for the national government to clearly determine the scope."

The NRA is still reviewing the safety of Tomari units 1 and 2.

In May 2022, the Sapporo District Court issued a ruling granting a request for an injunction against the operation of the three-unit Tomari plant. A lawsuit filed by about 1200 plaintiffs, including local residents, in November 2011 claimed the plant has insufficient countermeasures against earthquakes and tsunamis and called for it to be decommissioned. An appeal by Hokkaido EPC against that decision is currently being heard at the Sapporo High Court.