Since Hokkaido Electric Power submitted its application in July 2013, the review has taken nearly 12 years—the longest safety screening period for any nuclear reactor under Japan’s post-Fukushima safety standards. Much of the delay stemmed from extensive evaluations required to confirm the absence of active faults at the site. While most safety upgrades are complete, a 19-meter seawall, designed for tsunami protection, is still under construction, having begun last year, on March 28, 2024.
With Tomari-3 meeting regulatory requirements, the total number of Japanese reactors passing the new standards has now reached 18. However, further steps—including approval of operational safety programs and securing consent from local governments—remain necessary, particularly from the municipalities of Tomari Village, Kyowa Town, Iwanai Town, Kamoenai Village, as well as from Hokkaido Prefecture.
In Hokkaido, significant developments in energy-intensive industries in recent years have included the semiconductor company Rapidus Corporation, headquartered in Tokyo, which is constructing a new production facility in Chitose City as part of a national strategy to boost next-generation semiconductor manufacturing. In addition, SoftBank Corp. plans to build one of Japan’s largest data centers in Tomakomai City. Those next-generation semiconductors are expected to underpin advances in fields like artificial intelligence (AI), autonomous driving, 5G communications, and quantum computing, enhancing Japan’s international competitiveness. Many other companies also plan data center projects in Hokkaido.
According to a January 2025 report from the Organization for Cross-regional Coordination of Transmission Operators (OCCTO), electricity demand in Hokkaido (at transmission ends) is projected to rise significantly: from an estimated 29.214 TWh in FY24 (ending March 31, 2025) to 32.895 TWh in FY34 (ending March 31, 2035). The restart of Tomari-3 is thus expected to play a crucial role in ensuring a stable power supply in the region.
At a press conference following the NRA meeting, Chairman Shinsuke Yamanaka emphasized continued rigorous safety evaluations. Responding to a question about the lengthy review period, he acknowledged the importance of improving regulatory efficiency but reiterated that fundamental improvements in the review process are necessary moving forward.
