After the 2011 accident on the Fukushima Daiichi Nuclear Plant, Japan stopped all nuclear energy manufacturing. In the present day, the nation is restarting reactors, rewriting its vitality regulation, and recasting nuclear energy as a pillar of nationwide and regional safety reasonably than a legal responsibility to be managed. South Korea, its neighbor and rival in reactor exports, is shifting alongside a parallel observe, regardless of a change of presidency that briefly appeared to threaten the other.
Collectively, the 2 international locations are reshaping the nuclear politics of Northeast Asia and doing so more and more in live performance with Washington, as vitality coverage folds into the broader structure of trilateral safety cooperation.
The unresolved query behind each international locations’ restarts is what to do with the spent gasoline piling up at reactor websites. I explored one effort to resolve that concern earlier this month in a go to to Japan’s Horonobe Underground Analysis Laboratory. There, lots of of meters beneath the floor, engineers are testing whether or not the geological disposal strategies each nuclear nation is relying on really maintain up over time. Horonobe is a analysis web site, nevertheless, not a repository, and Japan nonetheless has no designated location for everlasting waste disposal. That hole has not slowed the political momentum above floor.
Earlier than 2011, nuclear energy equipped roughly 30 p.c of Japan’s electrical energy. After the meltdown at Fukushima Daiichi, each business reactor within the nation was taken offline, and public opinion turned sharply in opposition to nuclear energy. What adopted was over a decade of dependence on imported liquefied pure gasoline and coal, at a value Japan, which imports about 90 p.c of its major vitality, couldn’t maintain indefinitely, particularly as international gasoline markets tightened after Russia’s invasion of Ukraine in 2022.
The return to nuclear energy started in earnest with Prime Minister Kishida Fumio’s Inexperienced Transformation (GX) coverage, launched in 2022. The GX Primary Coverage, authorized by the Cupboard in February 2023, explicitly dedicated the federal government to restarting reactors already cleared by regulators and to constructing next-generation designs.
The Seventh Strategic Power Plan, authorized by the Cupboard in February 2025 together with the accompanying GX2040 Imaginative and prescient, cemented nuclear energy’s return as authorities coverage reasonably than a short lived emergency measure. In early 2026, that coverage produced its most tangible end result but: the restart of Unit 6 at Tokyo Electrical Energy Firm’s Kashiwazaki-Kariwa plant, the world’s largest nuclear facility by capability. Maybe extra pointedly, it’s run by the operator straight chargeable for Fukushima Daiichi. Such a restart would have been politically unthinkable a decade in the past.
The motivation is clear. New public funding for information middle and semiconductor services, price over a trillion yen, requires that the electrical energy used come fully from renewable or nuclear sources. That sends an unambiguous sign that Tokyo now considers nuclear vitality to be indispensable to industrial coverage, not simply decarbonization.
South Korea is shifting alongside an analogous trajectory, even when it as soon as appeared to be headed in a special path. President Lee Jae-myung took workplace in June 2025 after having campaigned on skepticism towards nuclear energy. Lee argued that the expertise was inherently harmful and that the nation’s reactor-heavy era combine wanted re-examining in favor of renewables. Seven months later, confronted with polling displaying sturdy public assist for nuclear vitality and with surging electrical energy demand from an AI-driven information middle increase, his authorities reversed course.
Seoul confirmed it might proceed with two new massive reactors beneath the eleventh Primary Plan for Electrical energy Provide and Demand, which targets a nuclear share of practically 32 p.c by 2030 and over 35 p.c by 2038. In August 2026, Lee’s authorities went additional, naming small modular reactors and nuclear fusion amongst seven applied sciences it needs to ascertain as future development engines for the South Korean financial system.
Korean reactor expertise is already aggressive with Western distributors. Across the identical time Lee took workplace, Korea Hydro & Nuclear Energy signed a contract to construct two APR-1000 reactors in Dukovany, Czechia, a deal price roughly $18.6 billion. The corporate has since signed cooperation agreements masking nuclear growth within the Philippines, small-reactors research with Singapore, and full fuel-cycle cooperation with France’s Orano. South Korea, which imports roughly 90 p.c of its personal vitality wants and round 30 p.c of its low-enriched uranium from Russia, is treating nuclear exports and home vitality safety as two sides of the identical coverage.
In July 2026, nuclear vitality turned an space of curiosity for trilateral cooperation between the US and its two East Asian Allies. Japan, South Korea, and the US agreed to collectively develop and export small modular reactors throughout the Indo-Pacific, explicitly extending their trilateral safety partnership into business nuclear cooperation.
With Russia and China as the one life like nuclear distributors for a lot of creating international locations, Washington has a transparent curiosity in making certain that Japan and South Korea enter the race. It could profit Washington if its two Northeast Asian allies, reasonably than Beijing or Moscow, change into the default suppliers of reactor expertise to the remainder of the area.
For Tokyo and Seoul, folding nuclear commerce into the trilateral safety relationship additionally affords insurance coverage in opposition to the awkward incontrovertible fact that each international locations’ export ambitions nonetheless run by means of Washington’s non-proliferation guidelines and, in South Korea’s case, the 123 Settlement governing nuclear cooperation with the US.
Japan’s personal export potential stays constrained exactly as a result of its home restart remains to be incomplete. Barely a handful of reactors are again on-line out of the roughly three dozen that existed earlier than 2011. That leaves South Korea, for now, because the extra credible reactor exporter of the 2.
What the restart narrative tends to depart out is that neither nation has solved the issue I discovered researchers nonetheless puzzling over at Horonobe: Japan has no working deep geological repository and no web site formally designated to host one. Meaning the used gasoline accumulating at reactor websites, together with on the restarted Kashiwazaki-Kariwa plant, has nowhere everlasting to go. South Korea faces the identical downside, with home opposition to any proposed storage web site constantly extra intense than opposition to reactors themselves.
That hole issues for the trilateral SMR push, too. Exporting reactor expertise to Southeast Asia or the Pacific Islands with out a credible regional reply on waste administration invitations the identical criticism that has dogged nuclear energy at house in each international locations: that the business is healthier at constructing political consensus for brand spanking new development than for coping with what development leaves behind.
For now, Northeast Asia’s nuclear revival is a narrative about vitality safety, industrial competitiveness, and alignment with Washington in opposition to Chinese language and Russian reactor diplomacy. However beneath all these developments lurks the unanswered query of what to do with the growing quantities of nuclear waste. That will find yourself mattering as a lot to the area’s vitality future as any restart or export deal introduced to this point.