Please zoom in or out and select the base layer according to your preference to make the map ready for printing, then press the Print button above.

The failed fast breeder reactor, Monju, Japan


Monju (in Tsuruga, Fukui Prefecture) was seen as a pillar of Japan’s nuclear fuel recycling program because it is designed to burn plutonium retrieved from huge stockpiles of spent fuel produced at nuclear power plants. Moreover, fast-breeder reactors are supposed to produce more plutonium than they burn while generating power. But Monju has operated on only 250 days over more than two decades because of many accidents, including a sodium coolant leak at the reactor in December 1995. The sodium coolant used in fast-breeder reactors is highly flammable and  very difficult to handle. So far, no country has developed a fast-breeder reactor for commercial purposes.

 On January 27, 2003 the Nagoya High Court's Kanazawa branch had handed down a historic ruling nullifying the government's 1983 permission for construction of Monju. The verdict recognized three main areas in which the Nuclear Safety Commission's (NSC) pre-construction safety review was inadequate. However, this court decision was later reversed. (5). Finally, in September 2016 it was reported that the government decided to cut its losses on the ¥1 trillion Monju fast-breeder reactor, pulling the plug on the project after years of mishaps, cover-ups and waste. [1]  Monju dates back to the 1980s, when work began amid the realization of a need to reduce reliance on fossil fuel. Almost all oil, coal and gas burned in Japan is imported.

Monju not only absorbed taxpayer money, but also suffered repeated accidents and mismanagement while only going live for a few months during its three-decade existence.

The Monju reactor reached criticality for the first time in 1994 but was forced to shut down in 1995 after the leak of sodium coolant and a fire. There was an attempt at a cover-up.

In November 2012, it emerged that the operator, Japan Atomic Energy Agency, had failed to check as many as 10,000 of Monju’s components, as safety rules require. The Nuclear Regulation Authority declared that the government-affiliated JAEA was “not qualified as an entity to safely operate” Monju.

It told the government either to find an alternative operator or scrap the project. The government was unable to find new management. Meanwhile, decommissioning Monju after 2016 will revive international concerns over Japan’s massive plutonium stockpile, extracted from spent fuel at the nation’s dozens of conventional nuclear power plants.

The stockpile is estimated at 48 tons of plutonium, enough to produce thousands of atomic bombs.

With no way to consume plutonium directly, the government plans to continue using MOX fuels — a mix of plutonium and uranium — in conventional nuclear reactors.

But most commercial reactors remain idle in the wake of the 2011 Fukushima nuclear disaster. The No. 3 reactor of the Ikata nuclear power plant in Ehime Prefecture is currently the sole active unit that uses MOX fuel.   Allegations of corruption are frequent.  "Massive amounts of tax money were funneled into the prefecture by the Liberal Democratic Party for all sorts of uses. Some were noble (construction of modern train stations, schools, hospitals and social welfare facilities). Some were corrupt (propaganda museums that played down the risks of nuclear power, all expense-paid “study”

tours to Europe’s nuclear reactor towns for local residents that included sightseeing trips to Paris). Nobody really knows how much money, directly and indirectly, went to Fukui and Tsuruga over the decades for “bearing the burden of Monju.” (6)

Basic Data

Name of conflict:The failed fast breeder reactor, Monju, Japan
State or province:Fukui Prefecture
Location of conflict:Tsuruga
Accuracy of locationHIGH (Local level)

Source of Conflict

Type of conflict. 1st level:Nuclear
Type of conflict. 2nd level:Nuclear power plants
Specific commodities:Plutonium

Project Details and Actors

Project details

Tsuruga already hosted two conventional reactors and in 1983 preparations began for the construction of a new fast-breeder reactor called Monju.

Monju functioned for less than a year since its completion in 1994. The fast-breeder reactor — a cornerstone of Japan’s atomic energy strategy dating back to the 1950s — would use spent nuclear fuel from other atomic plants and is designed to produce more fuel that it consumes. The reactor, named after the Buddhist deity of wisdom, has barely operated since it first generated electricity in 1995, the year it suffered a sodium leak that led to a fire and subsequent attempted cover-up. Safety problems have continued to plague the facility ever since.

“The potential closure of Monju would be a major blow not just to the fast-breeder community in Japan, but also those supporting reprocessing of spent fuel,” M.V. Ramana, a professor at Princeton University’s Nuclear Futures Laboratory, said by email. [2]

Decommissioning will be big business, Monju means abandoning a project that has devoured more than 1 trillion yen ($9.82 billion) of government funds. According to other sources [3] the government has already spent 1.2 trillion yen (US$12bn) on Monju. The government calculated that it would cost another 600 billion yen (US$6bn) to restart Monju and keep it operating for another 10 years. Decommissioning has a hefty price-tag. According to a 2012 estimate by the Japan Atomic Energy Agency, decommissioning Monju will cost an estimated 300 billion yen (US$3bn).

Project area:100
Level of Investment for the conflictive project13,000,000,000 USD
Type of populationSemi-urban
Start of the conflict:1994
Company names or state enterprises:Japan Nuclear Cycle Development Institute (JNC), owner of Monju from Japan
Relevant government actors:JAPA, Japan Atomic Energy Agency
Government of Japan
Nuclear Regulation Authority
Environmental justice organizations (and other supporters) and their websites, if available:- Masaichi Miyashita, heads the secretariat of an anti-nuclear group in Fukui Prefecture (2016)
- "Stop Monju" and Citizens Nuclear Information Center, in 2001 campaigning for a million petition signatures for the scrapping of Monju FBR.
- 2010: December 8 is “Phase Out Nuclear Energy Day” in Japan. The “Phase Out Nuclear Energy Day” campaign, which now includes a wide range of people, is supporting campaigns around country December 8 is the anniversary of Monju's sodium leak and fire in 1995.
- Wise International.
- Citizens' Nuclear Information Center, Japan.
- Abbot of Myotsu-ji, a Shingon Omuro temple in Wakasa Bay in Fukui Prefecture

Conflict & Mobilization

IntensityMEDIUM (street protests, visible mobilization)
Reaction stagePREVENTIVE resistance (precautionary phase)
Groups mobilizing:International ejos
Local ejos
Local scientists/professionals
Religious groups
“Japan has about 48 tons of plutonium stockpiled domestically and in Europe, and we need to be careful. The plutonium could be converted into nuclear weapons, and we need to make sure it’s not used for this purpose,” said Tetsuen Nakajima, abbot of Myotsu-ji, a Shingon Omuro temple in Wakasa Bay in Fukui Prefecture, and a long-time anti-nuclear activist.[4]
Fisher people
Forms of mobilization:Lawsuits, court cases, judicial activism
Media based activism/alternative media
Objections to the EIA
Public campaigns
Street protest/marches


Environmental ImpactsVisible: Fires
Health ImpactsVisible: Accidents, Exposure to unknown or uncertain complex risks (radiation, etc…)


Project StatusStopped
Conflict outcome / response:Corruption
Court decision (undecided)
Project cancelled
Proposal and development of alternatives:Anti-nuclear rally calls for more than just a Monju shutdown By RYUJI KUDO/ September 23, 2016. Thousands of anti-nuclear demonstrators gathered in Tokyo on Sept. 22, 2016 to demand the government go beyond decommissioning the troubled Monju prototype fast-breeder reactor and abandon its plans to restart other nuclear power plants. “We definitely don’t need the money-sucking and dangerous Monju,” said Hisae Sawachi, a writer and a member of the organizing committee of the demonstration, which took place under the banner “No nukes, No war.” “Why don’t government officials have the courage to close down all the other nuclear power plants?”
The rally, at Yoyogi Park in Tokyo’s Shibuya Ward, followed the government’s decision this week to unplug the reactor, which has hardly generated any electricity despite the more than 1 trillion yen ($9.9 billion) spent on it over two decades.
Masaichi Miyashita, who heads the secretariat of an anti-nuclear group in Fukui Prefecture, told the rally that officials in Tsuruga in the prefecture, where the reactor is situated, are opposed to the government decision to decommission the reactor and want to keep it.
Do you consider this an environmental justice success? Was environmental justice served?:Not Sure
Briefly explain:Over two decades of technological failures. It was not the social opposition to nuclear power which won the day but rather the government that realized that Monju did not work, and that 10 billion dollars had already been uselessly spent.

Sources & Materials

References to published books, academic articles, movies or published documentaries

Restarting Monju - Like Playing Russian Roulette. 2009. CNIC

Citizens' Nuclear Information Center. Shinjuku-ku, Tokyo, 162-0065.

[1] Japan to scrap troubled ¥1 trillion Monju fast-breeder reactor BY REIJI YOSHIDA. SEP 21, 2016

[2] Japan’s Monju reactor a costly hot potato no one wants to handle, by Emi Urabe and Stephen Stapczynski

[4] Nuclear cash cow Monju now a liability for residents as plant faces ax,

by Eric Johnston

(6) Fukui poised to benefit from decision to scrap Monju, by Eric Johnston

(5)JAPAN'S SUPREME COURT SNUBS CITIZENS OVER MONJU. Nuclear Monitor Issue: #629. 10/06/2005. Attempts by Japanese citizens' to seek protection from the legal system were struck a cruel blow today when the Supreme Court overturned an earlier Nagoya High Court verdict, which had invalidated the license approval for the Monju fast breeder reactor in Tsuruga, Fukui Prefecture.

Related media links to videos, campaigns, social network

[3] 5 October 2016, Dr Jim Green (Renew Economy), national anti-nuclear campaigner with Friends of the Earth Australia and editor of the Nuclear Monitor newsletter published by the World Information Service on Energy.

Citizens' Nuclear Information Center (information on nuclear issues in Japan, including Monju).

Rokassho. DECEMBER 8: NUCLEAR PHASE OUT DAY. Nuclear Monitor Issue: #721. 16/12/2010. Kazuhide Fukada

Japan: Protest against planned reopening of Monju. Nuclear Monitor Issue: #560. 21/12/2001. About 750 people took part in a rally on 8 December to commemorate the 1995 accident at Monju, Japan's prototype fast breeder reactor (FBR), at Tsuruga City, Fukiui Prefecture. The demonstrators further expressed their opposition to the planned restarting of Monju.

Other comments:Keiji Kobayashi, a former nuclear physics instructor and fast-breeder expert at Kyoto University Research Reactor Institute, is a longtime opponent of Monju. He says Japan might not be done entirely with fast-breeder reactors. “There are unanswered questions about what will happen to not only Monju but the fast-breeder reactor program in general.” [4].

Meta information

Last update18/08/2019
Conflict ID:2477