Tomari Nuclear Restart Slips Past 2027 as Japan Orders Fresh Construction Review
A new September regulatory review of Tomari's construction plan makes 2027 restart unlikely, extending Japan's nuclear approval queue ahead of its 2040 target.
Hokkaido Electric Power's Tomari nuclear power plant will undergo an additional regulatory review of its construction plan in September (2026), Hokkaido Shimbun Digital reported, placing a 2027 restart effectively beyond reach as approval delays compound.4
Japan's 2040 energy plan sets nuclear at 20% of the electricity mix, up from under 10% in 2025, the Economist reported in May (2026). Getting there would require nearly all 21 eligible reactors to operate. The country currently has 15 running. Three more have cleared safety reviews but remain idle. Eighteen, Tomari among them, are still working through regulatory approval, and the pace of that process has consistently lagged what government timelines assumed.1
Regulatory approval cycles have become the central bottleneck. Lengthy licensing processes threaten to push project schedules well past initial estimates across the whole fleet, according to a GlobalData analysis reported by Asian Power on August 18 (2026). Analyst Attaurrahman Ojindaram Saibasan said pre-2011 reactors are being requalified alongside safety upgrades. But community mistrust, persistent since the 2011 Fukushima accident, complicates even facilities with relatively clean technical records. Local consent does not follow automatically from a regulatory clearance.4
Regulatory clearance, in any case, is not sufficient on its own. Waste management and storage remain unresolved across Japan's fleet, Asian Power reported. These issues operate on a separate track from the safety review process. A plant that advances through one set of requirements can find itself blocked by another, and Tomari's additional construction review extends the timeline before any of those downstream decisions can be reached.4
Alternative generation is not filling the gap quickly enough. Wind projects in Japan must meet the same earthquake standards applied to multi-storey buildings. Solar development on abandoned farmland is limited by land-use regulation. Transmission capacity is insufficient to move renewable power to demand centres reliably, the Economist reported in May (2026). None of these barriers is near resolution.1
Japan's operating reactors are also running below potential. KEPCO set its nuclear capacity utilization rate for fiscal year 2026 at 70.5%, a 10.4-percentage-point decline year-on-year, Japan NRG Weekly reported. Extended inspections at Takahama units 1 and 2 for internal structure replacement, plus steam generator work on units 3 and 4, drove the figure lower. The plants already in service carry significant maintenance loads that limit how much slack exists elsewhere in the operating fleet.3
South Korea offers a recent reference point. Kori unit resumed operations in early April (2026) after a 35-month outage, following safety inspections and facility improvement work, World Nuclear News reported. One reactor back online after nearly three years is a concrete outcome. Japan's 2040 target implies something closer to a dozen comparable results, on a faster schedule than anything the post-Fukushima decade delivered.2
The arithmetic has not yet become unworkable. The three reactors that have received safety clearances but remain idle represent faster potential additions than plants still in full review. Yet the approval queue has historically moved in years rather than months, and Tomari is now committed to that timeline for longer than planned.1
The September (2026) construction review is Tomari's next concrete decision point. A clean outcome could open a 2028 or 2029 restart window. Further requirements would push that further still and remove the plant from Japan's near-term nuclear count. The government's 2040 goal depends on a chain of approvals that must accelerate significantly from the pace of the past several years, and each individual extension makes that acceleration harder to achieve.1,4