Japan’s Nuclear Regulation Authority (NRA) has approved a draft screening report that found that unit 3 at Hokkaido Electric Power Company’s Tomari NPP complies with new post-Fukushima safety standards. NRA effectively confirmed that the reactor meets the safety standards, which is a prerequisite for its restart. The report is expected to be formally adopted this summer following a period for public comments.
With semiconductor and data centre businesses projected to boost the prefecture’s electricity demand, Hokkaido Electric plans to restart Tomari 3 after completing the construction of a seawall by March 2027, along with other mandatory safety measures.
The company applied to NRA for the review in July 2013. The focus of the review included whether geologic faults on the territory of the power plant were active. The nuclear watchdog is still reviewing the safety of units 1&2.
Hokkaido Electric has 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 – and raised the height of potential tsunami it can withstand from 7.3 to 17.8 metres. The company had built a 16.5-metre-high seawall in 2014, but it will increase it to 19 metres based on NRA’s advice on the possibility of liquefaction of soil. The reactor will also be prepared for an accumulation of volcanic ash to a depth of 40 centimetres.
Hokkaido Electric President Susumu Saito noted that it took more than 11 years to evaluate the faults on the site due to a lack of specialised knowledge. “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,” NHK quoted him as saying.
Tomari 3, which began operation in 2009, is Japan’s newest reactor. The cost of construction for the new safety measures has risen to about JPY515bn ($3.6bn) from over JPY90bn for all three reactors.
In 2022, Sapporo District Court ordered an injunction against the operations of the reactor after a lawsuit filed by local residents, ruling that the reactor failed to meet safety standards for tsunamis. Hearings on the appeal against the ruling currently being heard at the Sapporo High Court.
The consent of local governments will be required before Tomari 3 can restart. Hokkaido Governor Naomichi Suzuki said although the review is in its final stage there still has to be a public consultation. “When specific details are presented, we would like to respond appropriately based on discussions in the prefectural assembly…. 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.”
