When Japan released its latest energy plan, most of the headlines focused on a single number: nuclear power is expected to provide around 20% of the country’s electricity by 2040.
That target would have seemed unlikely fifteen years ago. In the years following the Fukushima accident, the national conversation revolved around reducing dependence on nuclear energy. Many reactors remained idle, public confidence was badly shaken, and few politicians were eager to argue for a larger role for nuclear power.
Today, the discussion looks very different. Japan is extending reactor operating lives, considering next-generation reactor designs, and openly acknowledging that nuclear energy will remain part of its long-term energy strategy. The direction of travel is clear. What is far less certain is how quickly the country can get there.
The reason lies in a feature of Japan’s post-Fukushima system that often receives less attention than reactor restarts or energy targets.
The Japanese government does not control the pace of nuclear expansion.
Following the Fukushima accident, Japan created the Nuclear Regulation Authority (NRA) and gave it a level of independence that fundamentally changed how decisions are made. The regulator’s responsibility is straightforward: determine whether reactors satisfy safety requirements. National energy targets, electricity demand forecasts, and industrial policy goals are not part of that decision-making process.
That distinction matters more today than at any point since 2011.
Japan’s latest energy plan assumes a larger role for nuclear power at a time when electricity demand is expected to grow. Artificial intelligence is driving investment in data centers around the world. Governments are competing to attract semiconductor manufacturing and other energy-intensive industries. At the same time, Japan’s GX (Green Transformation) strategy calls for deep emissions reductions while maintaining economic competitiveness.
Those ambitions require large amounts of reliable, low-carbon electricity.
Yet every reactor still has to pass through the same review process.
More than a decade after the new regulatory framework was introduced, fewer than half of Japan’s operable reactors have returned to service. Utilities have invested heavily in upgraded safety systems, revised emergency procedures, higher seawalls, and strengthened protections against natural disasters and security threats. Even after those investments, reviews often take years.
For utilities, that timeline can be frustrating. For regulators, it reflects the purpose of the system itself.
The Fukushima accident changed more than Japan’s energy policy. It also changed expectations about how decisions should be made. Public confidence was damaged not only by the accident, but by the perception that regulators, government officials, and the industry had become too closely aligned. Rebuilding that confidence required a framework capable of making unpopular decisions when necessary.
As a result, Japan now operates with a built-in tension. Policymakers can envision the country’s energy mix in 2040. Regulators focus on whether a specific reactor meets today’s safety standards. Utilities plan investments years in advance. Local communities expect careful reviews and clear explanations before accepting a restart.
Everyone is participating in the same energy transition, but they are approaching it from different responsibilities.
This has implications far beyond Japan.
Around the world, interest in nuclear energy is growing again. Rising electricity demand, climate targets, and concerns about energy security have pushed many governments to reconsider the role of nuclear power. Discussions often focus on reactor technology, fuel supplies, construction costs, and deployment schedules.
Japan’s experience highlights another factor that receives less attention.
A country can decide that it wants more nuclear energy. Translating that goal into operating reactors requires institutions that are viewed as credible by the public. That process is rarely fast, and it becomes even slower after a major accident.
For that reason, Japan’s nuclear story today is about more than megawatts or energy targets. It is also a test of whether an independent regulatory system can support the expansion of nuclear power while maintaining the public confidence it was designed to protect.
Japan has already made one decision. Nuclear power will remain part of the country’s future energy mix.
The harder question is whether the institutions created after Fukushima can deliver that future at the pace policymakers now envision. The answer will shape not only how many reactors return to service, but also how Japan balances energy security, economic competitiveness, and decarbonization in the decades ahead.