Why Japan Is Reconsidering Nuclear After Fukushima
Fifteen years after the worst nuclear disaster since Chernobyl, Japan just restarted the world's biggest nuclear plant — and the reasons tell you everything about where energy is heading.
March 11, 2011 didn’t just destroy a power plant. It destroyed a national consensus. When the earthquake and tsunami triggered meltdowns at Fukushima Daiichi, Japan shut off all 54 of its reactors and swore — loudly, officially, repeatedly — that it would wean itself off atomic energy. Public support for nuclear power, which had sat at 62% before the disaster, collapsed overnight. By mid-2011, nearly three-quarters of Japanese voters wanted an immediate or gradual phase-out. The backlash felt permanent.
It was not permanent. In February 2026, TEPCO — the very company that caused Fukushima — fired up Unit 6 of the Kashiwazaki-Kariwa Nuclear Power Station in Niigata Prefecture, the world’s largest nuclear plant by installed capacity. The reactor achieved commercial operation in April 2026. This wasn’t a quiet technical milestone. It was a loud, politically charged reversal of the post-Fukushima order, and it raises a genuinely important question: what changed?
The short answer is: almost everything. Energy prices, geopolitics, climate commitments, and a tsunami of AI-driven electricity demand all converged to make nuclear look a lot less scary than it did when the rubble was still warm. But the longer answer is more complicated, more interesting, and honestly more honest about the gap between Japan’s ambitions and its current reality.
The policy shift that nobody called small
In February 2025, Japan’s cabinet approved its Seventh Strategic Energy Plan — and the most significant thing about it wasn’t what it added, it was what it deleted. For the first time since 2011, the government removed the phrase “reducing nuclear dependency as much as possible” from its official energy policy. That phrase had sat in every iteration of Japan’s energy plan since the Fukushima accident. Deleting it was, in policy terms, the equivalent of tearing down a memorial plaque.
The new plan is explicit: nuclear power should supply around 20% of Japan’s electricity by 2040, up from just 8.3% in 2024. Renewables should reach 40–50%. Fossil fuels, currently generating around 70% of Japan’s power, drop to 30–40%.
A few things stand out about this plan:
It permits new reactor construction for the first time since 2011
It replaces the goal of “minimizing” nuclear with “maximizing” the use of existing plants
It acknowledges, unusually, that there are two scenarios — one where nuclear and renewables dominate, and one where they fall short, requiring continued fossil fuel use
The 20% nuclear target for 2040 is actually a decade-long retreat from the prior plan’s identical target for 2030, which was missed by a mile
That last point matters. The Council on Foreign Relations’ analysis of Japan’s post-Fukushima energy position notes that Japan’s latest plan “explicitly acknowledges the need for flexibility” — which is a diplomatic way of saying nobody is fully confident any of this will happen on schedule. Ambition and arithmetic are two very different things.
The economics that made nuclear inevitable
Here’s a number worth sitting with: $70 billion. That’s roughly how much Japan spent on liquefied natural gas and coal imports in 2024 alone, according to OilPrice.com analysis of Japan’s energy position. Japan imports 60–70% of its electricity resources. For a country with almost no domestic fossil fuel reserves, that’s not an energy policy — it’s a permanent invoice.
The Ukraine war made everything worse. When Russian gas flows to Europe tightened after 2022, LNG became a seller’s market globally. Japan, which uses LNG for roughly a third of its power generation, got squeezed badly. The Institute for Energy Economics and Financial Analysis tracks Japan’s LNG exposure closely and found that Japan’s total fossil fuel import bill nearly doubled between 2021 and 2022, pushing the trade deficit to a record ¥20 trillion ($155 billion). Even after moderation, fossil fuel imports in 2025 remained well above pre-2022 levels. The yen’s depreciation made every barrel and every tanker shipment more expensive in local currency terms.
Nuclear power doesn’t eliminate Japan’s energy insecurity. But it reduces it in a specific and appealing way: 🏭 once a reactor is running, the marginal cost of electricity is low and stable, not subject to LNG spot prices or Strait of Hormuz disruptions.
Then AI arrived and made the problem even more urgent:
Japan’s data center electricity consumption was 19 TWh in 2024
By 2034, that figure is projected to reach 57–66 TWh — a tripling in a single decade
This boom is driven by $28 billion in investments by hyperscalers including Google, Microsoft, and Oracle
Japanese data centers will account for 60% of total power demand growth through 2034, per Wood Mackenzie analysis
A country that already struggles to generate enough clean power is being asked to power a continental-scale AI buildout. 💡 Something had to give.
The restart reality check
Here is where honesty becomes important. Japan’s nuclear “revival” is real, but it is not going as fast as the headlines suggest. The numbers tell a sobering story:
Before Fukushima: 54 reactors generating roughly 30% of Japan’s electricity
Technically operable fleet today: 33 reactors
Currently operating: 15 reactors
Received restart approval but still offline: 3
Under regulatory review: 6
Never filed a restart application: 8
The Diplomat put this starkly on the 15th anniversary of Fukushima: Japan’s nuclear story is “a widening gap between political ambition and physical reality.” The capacity factor for restarted plants reached a respectable 80.5% in 2024 — showing that plants that are running do run well — but getting plants approved and running is the problem that nobody has solved. 🔬
Restart costs run $700 million to $1 billion per unit, regardless of the reactor’s size or age. Safety upgrades mandated by Japan’s Nuclear Regulation Authority (NRA) are extensive and genuinely time-consuming. Some plants face local opposition that no cabinet minister can override by decree. The Shika-2 reactor, for instance, sits close to the epicenter of the devastating 2024 Noto Peninsula earthquake and faces obstacles that have nothing to do with political will.
The East Asia Forum’s assessment was blunter: “the nuclear revival is more wishful thinking than reality.” That’s harsh, maybe slightly unfair given the actual restarts that have happened, but the direction of the critique is fair. A government that previously promised 20% nuclear by 2030, failed, and then promised the same target by 2040 needs to explain why a decade of extra time will produce results that the previous decade didn’t.
What has actually changed is that the political cost of not restarting is now higher than the political cost of restarting. That’s a meaningful shift. It just doesn’t make engineering go faster.
Public opinion: a reluctant thaw
The moment that best captures Japan’s changed mood didn’t happen in Tokyo. It happened in Kariwa, a village of about 4,200 people next to the Kashiwazaki-Kariwa plant, where Mayor Shinada Hiroo expressed what the Christian Science Monitor described as “unwavering trust in the people who run the nuclear facility.” The mayor’s trust isn’t naive — it’s conditional and relational. TEPCO, he noted, has started paying “more attention to local matters.” That’s a different kind of accountability than regulatory compliance. It’s the slow, unglamorous work of rebuilding a relationship that was shattered.
Still, opinion is far from settled. When the Niigata prefectural assembly approved the bill clearing the way for Kashiwazaki-Kariwa’s restart in December 2025, 60% of Niigata residents didn’t think the conditions for restart had been met, and nearly 70% were worried about TEPCO’s ability to operate the plant safely, per Reuters reporting. Ayako Oga, 52, who fled the Fukushima disaster and still lives in Niigata with what she describes as PTSD-like symptoms, told Reuters: “We know firsthand the risk of a nuclear accident and cannot dismiss it.” 😔 Her old home is still inside the exclusion zone.
That’s the unresolved tension at the center of Japan’s nuclear revival. You can change a government policy document in a morning. Changing lived experience takes generations. The official acknowledgment that “there is no such thing as absolute safety” — uttered by nuclear officials as a statement of philosophical honesty — lands very differently in a town where the next exclusion zone would be someone’s actual neighborhood.
What does appear to be genuinely shifting is the attitude of younger Japanese. Reuters reported on engineering students in Fukushima prefecture who see nuclear power as a technology with a future, not just a source of trauma. Whether that generational shift translates into sustained public support for new construction is a real question — one worth watching closely. 🌱
Where SMRs fit into Japan’s nuclear future
Japan’s current restart push is almost entirely about existing large reactors, not next-generation technology. The country’s 7th Strategic Energy Plan does permit new reactor construction, but the plan’s focus is on making the most of plants already built. SMRs, according to Climate Scorecard’s 2025 analysis of Japan’s nuclear sector, are “projected for 2040 or later.” That’s a long runway.
But Japan is not sitting on the SMR sidelines. In March 2026, GE Vernova and Hitachi signed a formal Memorandum of Understanding to explore deploying the BWRX-300 SMR across Southeast Asia, specifically to incorporate Japanese suppliers into the SMR supply chain. The signing happened at the Indo-Pacific Energy Security Ministerial in Tokyo, in the presence of U.S. and Japanese government officials — which is less a coincidence and more a signal. Japan wants to be a supplier nation in the coming SMR era, not just a customer. 🚀
Hitachi GE Vernova’s BWRX-300 technology is already under construction at Ontario Power Generation’s Darlington site in Canada — on track to become the first SMR deployed in the Western world. Japanese companies including Mitsubishi Heavy Industries, Toshiba Group, and IHI are also in conversations about supporting U.S. reactor construction through up to $100 billion in potential partnerships announced via Japan’s nuclear cooperation framework.
The IEA’s roadmap for nuclear’s new era is explicit that SMRs — alongside large new conventional builds — could allow Japan to “reclaim technology leadership” in nuclear energy alongside Europe and the United States. That framing, “reclaim,” is deliberate. Japan was a major nuclear technology exporter before Fukushima. It wants that role back. Whether SMR economics cooperate is still genuinely uncertain. ⚡
The harder question for Japan is whether the domestic political path to new-build nuclear — not just restarts — is actually open. Permitting new construction in a country where every township near a potential site has veto-adjacent influence is a different challenge than permitting it on paper in a cabinet document. What’s your read: is Japan’s nuclear push a genuine energy transition or an elaborate game of kicking the fossil fuel dependency further down the road?