Fukushima Holds About 14 Million Cubic Metres of Removed Soil. Reuse Outside the Prefecture Began With Flower Beds at Two Government Buildings

Within 30 years of the start of interim storage (by March 2045)[1]. That is the deadline for completing the final disposal, outside Fukushima Prefecture, of soil removed during decontamination there. It is not an aspiration. It is a duty of the state written into law.

On 29 August 2026 one step toward that disposal took place. At a government building in Aoba Ward, Sendai, a flower bed was built using removed soil. Leaving aside demonstration projects inside Fukushima, this was the first such use outside Tokyo. A government building in Saitama followed.

The volume used across both sites was about 2 cubic metres.

The volume in storage is about 14 million cubic metres.

One caveat first: those two figures are not on the same footing. Inside Fukushima, demonstration projects such as the one in the Nagadoro district of Iitate are running at a scale these two beds do not approach. The 2 cubic metres is the first volume used outside Fukushima in something other than a demonstration project. What this piece follows is how things are moving outside the prefecture.

The deadline comes from a statute

It is worth establishing where the deadline comes from. The interim storage facility holds the soil until final disposal.

Under the Act on the Japan Environmental Storage and Safety Corporation (Act No. 44 of 2003), it is provided that measures necessary to complete final disposal outside Fukushima Prefecture shall be taken within 30 years of the start of interim storage[2]. The same document, a few lines earlier, puts it this way: the circumstance that the interim storage facility was accepted through an agonising decision by the local community[2].

The deadline sits there as a promise to the community that took the facility.

The volume, and how it is divided

The breakdown is published too. About 14 million m3 (as of the end of June 2025)[3]. Not all of it goes out of the prefecture.

About three quarters of the soil held at the interim storage facility can be used[1], with public works named as the route. The remaining quarter or so goes to final disposal outside the prefecture, after volume reduction.

Reuse is not a substitute for disposal. It is the step that shrinks how much has to be disposed of.

Where the 8,000 becquerel line comes from

The line between reusable and not is drawn by radioactivity concentration.

For reconstruction reuse, in light of the internationally established radiation safety standard limiting additional public exposure to 1 mSv per year, the annual additional dose is to be held at or below 1 mSv, with 8,000 Bq/kg or less as the concentration that satisfies this[4].

What that 8,000 protects is set out in the same document's footnote. It is set by model calculation so that the annual additional dose to the most exposed party, workers during construction, stays at or below 1 mSv[4]. Allowing for shielding by cover soil, the annual additional dose around the site is given as 0.017 mSv with 20 cm of cover soil above, and 0.00086 mSv with 50 cm[4].

The basis has been checked from outside as well. An expert mission from the International Atomic Energy Agency assessed the ministry's approach. Under appropriate management, using recycled soil at 8,000 Bq/kg or below can amply meet the dose criterion[4]. That is a conclusion of the final report published in September 2024. Japan's Radiation Council also found the draft standard appropriate on 27 February 2025.

The soil used in Saitama measured about 4,000 becquerels per kilogram, according to news reports. Half the standard.

The deadline is statutory; the start is around 2030

So far this is a story of standards and procedures accumulating. The problem lies in the schedule that follows.

As the state to aim for around 2030, the scenario for final disposal outside the prefecture and the candidate site selection process are to be made concrete, and the selection and survey of candidate sites are to begin[3].

What begins around 2030 is not disposal. It is the search for a place.

The closing section of the basic policy says as much. It is necessary to make concrete the path for the coming 20 years[4]. A 20-year path, still to be made concrete.

One of the three pillars is procuring consent

The basic policy rests on three pillars: promoting reconstruction reuse; building understanding and risk communication; and advancing work toward final disposal outside the prefecture.

A third of it is devoted to producing acceptance. And that pillar is not about the disposal site. From the standpoint of building broad public understanding of reconstruction reuse, the government will take the lead in creating early examples, beginning with consideration of use at the Prime Minister's Office[4].

That is what happened. The Ministry of the Environment's site lists potted plants using removed soil, as of March 2026, at the Prime Minister's Office, the Environment Minister's office and those of the state minister and parliamentary vice-minister, the Reconstruction Agency, the ministries of internal affairs, foreign affairs, defence, education, economy, land, finance, justice and agriculture, the Nuclear Regulation Authority, and the headquarters of the Liberal Democratic Party and Komeito.

Potted plants. The next step up was the flower beds in Sendai and Saitama.

What is counted is places, not volume

The roadmap has one more feature worth noting. Construction will proceed in sequence at nine central government offices in Kasumigaseki, expanding to annexes, regional branch bureaus and affiliated corporations[3].

The unit is offices. Not cubic metres.

The method for checking progress points the same way. A nationwide web survey and similar instruments will be conducted periodically to confirm this progress[4].

What gets measured is understanding. Across the full basic policy and the Reconstruction Agency material summarising the roadmap, no indicator tracking how much of the 14 million cubic metres has been drawn down appears (the roadmap document itself was not examined).

Spreading understanding and reducing volume are separate goals, so progress on the first does not carry the second. And if only the first can be reported as progress, the time left before the deadline never shows up in the numbers.

What starts to matter once a place is sought

As the Linear Shinkansen agreement in Shizuoka（このサイトの記事） showed, what a community finally asks for as a condition of acceptance is not more explanation but a procedure. Who can halt the work, and on what condition. Consent becomes a document only when it takes that shape.

For removed soil that procedure has not been written. What the basic policy offers is work to organise the siting conditions to be considered in selecting candidate sites for the final disposal facility[4]. The conditions are being organised, so they have not been stated.

As the design of resident participatory policy-making（このサイトの記事） set out, holding briefings and being able to shape a decision are different things. Stacking up the former does not produce the latter.

The composition of the promotion council does show how much weight the government places on this. The Chief Cabinet Secretary chairs it, the ministers for the environment and for reconstruction serve as vice-chairs, and every minister of state except the Prime Minister is a member. Councils containing the whole cabinet are rare.

That council was created in December 2024, adopted the basic policy in May 2025, and compiled the roadmap in August 2025. In August 2026 the first flower bed outside Fukushima was built. The gap between the size of the machinery and the volume moved is where this stands.

What to count in order to judge next

Consider what a municipality approached about accepting the material could actually use.

The first is how much volume reconstruction reuse has actually drawn down — in cubic metres rather than sites, and cumulatively. Without that, no one can see where their own share sits in the whole.

The second is how many cubic metres the roughly one quarter bound for final disposal currently amounts to. It is the figure that should fall as reuse advances, and it is exactly the volume a disposal site must take before the deadline. If it has not moved, what has grown is understanding, and nothing has shrunk.

As the structural analysis of small concessions for closed schools（このサイトの記事） set out, there is a fault line between a scheme being complete and projects actually moving. The standard, the guideline and the international assessment are all in place. With all of that in place, the volume moved outside Fukushima was 2 cubic metres. That is where August 2026 stands.

What counts as a result has to be decided before the work starts (designing outcome indicators（このサイトの記事）). Whether an indicator of volume is in place by the time site selection begins around 2030 is the fork in the road.

The deadline is written into law. What is not written is where the material goes.

A deadline with no destination — whose deadline is it?

Further Reading

• 核のごみをどうするか (What to Do with Nuclear Waste)（外部サイト、新しいタブで開きます） (Takatoshi Imada, Kota Juraku and Takashi Nakazawa, Iwanami Shoten). An account of why siting and consent stall in the geological disposal of high-level radioactive waste. The material differs, but the structure of a fixed deadline without a fixed place is the same.

References

Strengthening the Framework for Promoting Reuse Toward Final Disposal of Removed Soil Outside Fukushima Prefecture (20 December 2024) — Nuclear Emergency Response Headquarters (2024). Cabinet Secretariat

Basic Policy on Promoting Reuse Toward Final Disposal of Removed Soil Outside Fukushima Prefecture (27 May 2025) — Council for Promoting Reuse Toward Final Disposal of Removed Soil Outside Fukushima Prefecture (2025). Cabinet Secretariat

Efforts on Reconstruction Reuse Toward Final Disposal of Removed Soil Outside Fukushima Prefecture (3 October 2025) — Reconstruction Agency (2025). Reconstruction Agency

Efforts Toward Final Disposal Outside Fukushima Prefecture — Ministry of the Environment (2026). Interim Storage Facility Information Site

About Reconstruction Reuse — Ministry of the Environment (2026). Interim Storage Facility Information Site