Fukushima and Japan’s Return to Nuclear Power: 15 Years After the Disaster, Memory Is Fading, but the Problems Are Not Over

Author: Marco Arezio. Expert in circular economy, industrial sustainability, and production systems analysis. Founder of the rMIX platform.

Original publication: October 2020

Editorial update and fact-check: March 19, 2026

Reading time: 11 minutes

Fukushima, the disaster Japan has never truly closed

When writing about Fukushima, the first duty is precision. The 2020 text used the expression “triple uncontrolled atomic explosion,” but that is not technically correct. On March 11, 2011, the magnitude 9.0 earthquake and the subsequent tsunami caused the loss of electrical power and cooling systems at the Fukushima Daiichi nuclear power plant; in the days that followed, the cores of reactors 1, 2, and 3 suffered severe damage, with fuel melting, while the explosions that devastated the buildings were hydrogen explosions, not nuclear explosions in the proper sense. The IAEA’s technical literature and international reports on the disaster clearly describe this sequence: three reactors experienced meltdown or severe fuel damage, and the buildings of reactors 1, 3, and 4 were damaged by hydrogen explosions generated by overheating and internal chemical reactions.

This correction is not a mere lexical detail. It changes the way the entire event should be read. Fukushima was not only an industrial tragedy caused by an extreme natural event; it was also proof of how a society with very high technical capacity can suddenly find itself unprepared in the face of a chain of failures, loss of control, mass evacuations, and management problems that can last for decades. For this very reason, the memory of the disaster should never be treated as a closed archive, but as an active lens through which to assess Japan’s energy policy today.

From the freezing of nuclear power to its strategic return

Immediately after Fukushima, Japan progressively shut down its nuclear fleet, opening a period of rethinking that seemed destined to structurally reduce the role of atomic energy in the national energy mix. Fifteen years later, however, the picture has changed radically. The most important political turning point came with the Japanese government’s 7th Strategic Energy Plan, approved in 2025, which explicitly states the need to “maximize” both renewables and nuclear power, moving beyond the binary logic of the “renewables versus nuclear” debate. The document links this choice to energy security, decarbonization, and the need to guarantee stable electricity for an economy preparing for higher consumption driven by digitalization, semiconductors, and industrial transformation.

The numbers in the plan clearly show the scale of this shift. In its outlook to 2040, Japan aims to bring renewables to around 40–50% of electricity generation, nuclear to around 20%, and thermal power to 30–40%. The comparison with the starting point is revealing: according to the baseline scenario cited in the plan, the country came from an electricity mix made up of 22.9% renewables, 8.5% nuclear, and 68.6% thermal power, while its energy self-sufficiency rate stood at only 15.2%, with a target of rising to 30–40% by 2040. In other words, for Tokyo, nuclear power is no longer a taboo to be tolerated only residually, but one of the central levers for reducing dependence on foreign energy and containing the weight of imported fossil fuels.

This evolution helps explain the political meaning of the new official narrative. The Japanese government does not present the return to nuclear power as an erasure of Fukushima, but as a national necessity within a broader strategy of decarbonization and resilience. Yet this is precisely where the paradox emerges: the country is reviving nuclear power while the most serious accident in its contemporary energy history remains materially unresolved, with technical, environmental, and territorial problems that are far from settled.

2026 confirms that the return of nuclear power is no longer just theoretical

The revival is not merely programmatic. In 2026, the process of restarting reactors has become an operational reality. According to the most up-to-date reconstructions, Japan has brought 15 operable reactors back online after the long shutdown that followed 2011. The restart of Kashiwazaki-Kariwa Unit 6, a TEPCO facility and the world’s largest nuclear power station by installed capacity, has become the symbol of this new phase, not least because it is the first restart of a TEPCO reactor since Fukushima. Reuters and other industry sources reported that in March 2026 the commercial start-up of the unit was postponed yet again after a technical problem, a sign that the return to nuclear normality remains fragile even at the operational level.

This is also an important detail on the symbolic level. Japan is not merely “discussing” nuclear power: it is already reintegrating it into its electricity system. But every restart, especially when it involves TEPCO, is seen as a test of industrial reliability, regulatory credibility, and public trust. The fact that the return of Kashiwazaki-Kariwa has been accompanied by stoppages, inspections, and delays shows that the wound of Fukushima still weighs on social and institutional expectations, even if political language now tends to normalize the process.

Fukushima Daiichi is not a closed site: it is still a construction site of risk

The decisive point, in fact, is that Fukushima Daiichi does not yet belong to the past. TEPCO continues to manage the site as a massive and unprecedented decommissioning laboratory, and in its Mid-and-Long-Term Decommissioning Action Plan 2025 it openly acknowledges that the ongoing operations are “unprecedented in the world” and require continuous revision as new problems and new knowledge emerge. This is not a standardized dismantling project, but a sequence of interventions that must be constantly adapted.

This is especially true for the most difficult issue of all: the retrieval of fuel debris, that is, the highly radioactive materials produced by the melting of fuel in the damaged reactors. In 2025, TEPCO indicated that, for Unit 3, the preparation alone of the upper and lateral access routes needed for future retrieval operations could take approximately 12 to 15 years, depending on the technical options adopted. That figure alone is enough to dispel any impression that the Fukushima case is close to being “closed.” The hardest, most expensive, and most uncertain part of the work is not behind us: it still lies ahead.

ALPS-treated water: technical compliance does not mean the end of conflict

Among the most visible dossiers is that of the water treated through the ALPS system. Since 2023, TEPCO has begun releasing treated water into the sea, and the official 2025 reports show that the process has now entered a regular management phase. According to the updated roadmap, as of November 13, 2025, the site still contained 1,261,675 cubic meters of treated water in storage, while the total volume discharged into the ocean since the beginning of the operation had reached approximately 125,488 cubic meters by the completion of the fifth campaign of fiscal year 2025.

From a technical and radiological standpoint, the IAEA repeatedly confirmed in 2025 that the discharge program continues to meet international safety standards and that the associated monitoring programs are consistent with those standards.

Contaminated soil: the least discussed and most cumbersome problem

If water draws media attention, contaminated soil tells the story of the physical scale of the post-disaster landscape better than anything else. The Japanese Ministry of the Environment reported that by the end of July 2025, about 14.11 million cubic meters of removed soil and waste had already been transferred to interim storage facilities. Japanese regulations establish that their final disposal must take place outside Fukushima Prefecture by March 2045, but to achieve this the government is increasingly relying on volume reduction and so-called “managed recycling,” that is, the controlled reuse of lower-radioactivity materials in specific civil engineering works. In August 2025, a five-year roadmap was formally established precisely to promote this path and build public consensus around it.

Here too, however, technical compliance is not enough to untie the political knot. The IAEA has judged the Japanese approach to the management and possible recycling of a significant portion of these soils to be consistent with its safety standards, but the central question remains open: which territory, outside Fukushima, will truly accept the final transfer of the problem? In other words, Japan must not only find an engineering solution; it must find one that is territorially and socially acceptable. And it is often on this second front that the most rational technical strategies meet their greatest limits.

The number of evacuees has fallen, but normality has not returned everywhere

Another indicator of the gap between reconstruction and full normality is the condition of the evacuated population. The Reconstruction Agency reports that the number of evacuees in Fukushima Prefecture has fallen from a peak of about 165,000 to around 26,000 in June 2024, and that the population living in areas where evacuation orders have been lifted has gradually increased, reaching around 17,000 people in May 2024, compared with approximately 4,000 in April 2017. These figures document real progress. But they also show that the return has been neither total nor linear. Areas that remain difficult to reinhabit, special decontamination programs, infrastructure still to be rebuilt, and a highly uneven geography of return all remain.

And this is where the deeper meaning of memory emerges. Memory does not disappear when territories are partially reopened or when evacuation statistics improve. It disappears, rather, when reconstruction data are used to suggest that the chapter is substantially closed. But Fukushima is not closed. It is governed, monitored, partially stabilized, and administered with growing sophistication; it is not, however, concluded either technically or humanly.

The real question: can Japan revive nuclear power without having resolved Fukushima?

This is the question that remains on the table in 2026. From the standpoint of the Japanese state, the answer tends to be yes: the country needs greater self-sufficiency, fewer imported fossil fuels, more decarbonized electricity, and a more stable energy mix. From that perspective, the return of nuclear power is presented as an act of strategic realism. From the point of view of a critical observer, however, the picture is less reassuring. The revival of nuclear power is taking place in a seismic country, with a collective memory still wounded, with a devastated site that will require decades of work, and with disposal and social acceptance problems still far from a true resolution.

For this reason, it is less surprising than it may seem that, fifteen years after the disaster, the greatest risk is not the total erasure of Fukushima, but its gradual political normalization. The trauma is not denied; it is absorbed. It becomes a historical cost to be managed while nuclear power is once again used as a lever of industrial, climate, and energy policy. And it is precisely in this passage that memory risks weakening: not because no one remembers 2011 anymore, but because that memory no longer truly hinders present-day choices.

FAQ

Is Fukushima a completely resolved disaster?

No. The site is still in the decommissioning phase, with an official time horizon of 30 to 40 years, while the issues relating to fuel debris, treated water, contaminated soil, and some areas that remain difficult to reinhabit are still unresolved.

How many nuclear reactors have been restarted in Japan after Fukushima?

According to the World Nuclear Association, by February 2026, 15 reactors had been restarted, while others were still in the approval or preparation process.

Is Japan focusing more on renewables or on nuclear power?

On both. The 2040 energy plan aims for an electricity mix with renewables at 40–50% and nuclear at around 20%, while reducing the weight of thermal power generation.

Is the water released from Fukushima into the ocean still radioactive?

Yes. After ALPS treatment, tritium in particular remains, and it is managed through dilution and monitoring. The IAEA has stated that the discharge program continues to comply with international safety standards.

What will happen to the contaminated soil removed from Fukushima?

Japan plans final disposal outside the prefecture by March 2045 and is developing managed recycling programs for the lower-radioactivity fractions, according to guidelines published in 2025.

Authoritative sources for the revision

This rewritten article was updated using documentation from the IAEA, TEPCO, the Agency for Natural Resources and Energy/METI, the Reconstruction Agency of Japan, the Japanese Ministry of the Environment, the IEA, and the World Nuclear Association.