In the past year, only one nuclear reactor in Japan has received regulatory approval to restart. Even that does not guarantee that the facility will go online – a situation TEPCO knows all too well. Each year the country’s biggest utility announces plans to switch on its nuclear units and each year it fails to do so.

The stasis in Japan’s nuclear power sector was masked by a recent period of mild success: in each of the last two years, two reactors were restarted, bringing the total number of units able to generate electricity to 14. The outlook for the next two years is more problematic.

Since shutting all nuclear stations in the wake of the Great East Japan Earthquake in March 2011, Japan has struggled to revive the sector. Despite bursts of progress, the restart of the 33 reactors designated as operable is going slower than planned, mired in inspections and continuing upgrades. The cost of care and maintenance and new safety upgrades alone runs into trillions of yen.

Still, the government’s belief in the necessity of nuclear power in Japan has remained and has even strengthened based on the latest Basic Energy Plan draft, submitted in December 2024. Other commitments to nuclear energy were made at international forums such as COP28.

Last year, Tohoku Electric’s Onagawa Nuclear Power Plant Unit 2 (825 MW) restarted, shortly followed by Chugoku Electric’s Shimane Nuclear Power Plant Unit 2 (820 MW). Both are both BWRs, the same type as Fukushima Daiichi, marking the first BWR restart since 2011. These two reignited hope for the quicker restarts of other NPPs.

Given state backing, which reactors are likely to be brought back online next? Japan NRG takes a close look at how much of the nearly 20 GW in nuclear capacity that sits idle is likely to deliver electrons to the market in the near and mid-term future.