The Tomari Nuclear Power Plant is the only nuclear power plant in Hokkaido, Japan
Hokkaido Electric aims to restart Tomari Unit 3 by March 2027, following the completion of a new seawall and other required safety enhancements. The decision is driven by rising electricity demand in Hokkaido, particularly from semiconductor and data center industries. The company submitted its safety review application to the NRA in July 2013, focusing on assessing whether geologic faults at the site are active. The NRA continues to evaluate the safety of Units 1 and 2.
To enhance safety, Hokkaido Electric has strengthened the plant’s quake-resistant design, increasing its capacity to withstand seismic wave acceleration from 550 gals to 693 gals. The facility is also prepared for potential tsunamis, with the maximum wave height it can endure raised from 7.3 meters to 17.8 meters. A 16.5-meter seawall built in 2014 will be extended to 19 meters to address soil liquefaction risks. Additionally, the reactor is equipped to handle volcanic ash accumulation up to 40 centimeters deep.
Hokkaido Electric President Susumu Saito said: “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.” Saito noted that the 11-year fault evaluation process was delayed due to limited specialized expertise.
Tomari Unit 3, operational since 2009, is Japan’s newest reactor. The cost of implementing new safety measures has risen to approximately JPY515 billion ($3.6 billion), up from JPY90 billion for all three reactors. In 2022, the Sapporo District Court issued an injunction halting the reactor’s operations, citing inadequate tsunami safety measures. The case is under appeal at the Sapporo High Court.
Restarting Tomari Unit 3 requires approval from local governments. Hokkaido Governor Naomichi Suzuki said: “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.” A public consultation will precede final decisions.
This development reflects Hokkaido Electric’s efforts to balance energy needs with stringent safety requirements, ensuring the plant aligns with modern standards while addressing community and environmental concerns.
