You are here


Nuclear Monitor Issue: 

(June 10, 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.

(629.5696) CNIC - The Supreme Court failed to address the basic safety issues and simply rejected the citizens' argument on a technicality. After twenty years of brave struggle, the citizens have been snubbed by a totally unreasonable decision from a cold and distant Supreme Court.

CNIC expects that the government will use this to justify its fuel cycle and plutonium policies. However, just because the Supreme Court has endorsed the original license approval, it does not mean that Monju will ever become fully operational. There are still huge technical and obstacles to be overcome and it is highly doubtful whether fast breeder reactors can ever be economically competitive.

Furthermore, if fast breeders ever were to become a reality, we would be living in a plutonium economy. That in turn would mean living in a police state because the amount of plutonium required to operate just one commercial sized fast breeder reactor is enough to produce hundreds of nuclear weapons.


The 280 MW Monju prototype fast breeder reactor is located in Tsuruga, Fukui Prefecture and has been shut down since 8 December 1995 because of a sodium leak and fire accident. Preparations are currently underway for modifications designed to rectify various safety defects identified since this accident. These modifications are scheduled to begin in September this year and will continue until around February 2007. According to Japan Nuclear Cycle Development Institute (JNC), the owner of Monju, the plan is for operations to recommence around February 2008.

Citizens originally filed the lawsuit against the Monju prototype fast breeder reactor in September 1985. Since then it has been back and forth between the Fukui District Court and the Nagoya High Court, with the status before the 30 May decision being that the Nagoya High Court had adjudicated in 2003 in favor of the citizens who filed the suit. The license approval was found to be invalid according to that decision. The then Power Reactor and Nuclear Fuel Development Corporation (now JNC) applied for a licence in 1980 and approval was granted in 1983 after safety investigations by the then Science and Technology Agency and the Nuclear Safety Agency. For more details about this case, see:

Monju uses plutonium as fuel and sodium as coolant. Also a blanket of depleted uranium packed around the core absorbs neutrons, which escape from the reactor core. These neutrons convert some of the uranium into plutonium. These three characteristics of the fast breeder reactor give rise to a number of problems, including the following: (1) plutonium is a potential material for nuclear weapons; (2) the high temperature molten sodium circulating within the reactor is explosive when in contact with water.

The citizens' major arguments against Monju related to safety. Three major defects formed the basis of their claim that the license approval was invalid. These were as follows:

  1. The sodium leak and fire in 1995 revealed that the Monju approval failed to meet the required safety standards.
  2. The approval did not take into account the possibility of a high temperature rupture of pipes in the steam generator. Such a rupture would cause steam to come into contact with sodium, resulting in an explosion.
  3. The approval did not give adequate consideration to the possibility of a runaway nuclear reaction leading to the reactor core breaking up and releasing its radioactive contents.


There were also legal technicalities that needed to be argued. These revolved in particular around the issue of whether flaws in the approval process were 'clear' and 'serious' and whether the court was technically competent to make a judgment. The Nagoya High Court had ruled that the flaws did not have to be 'clear', that they were 'serious' and that it was competent to make the necessary judgment, given the serious flaws in the safety review process. However, the Supreme Court took the view that, except where the administration's judgment regarding the safety of the basic design was not reasonable, the administration's judgment should be respected.

The following link leads to a document produced by Green Action with answers to frequently asked questions about Monju:

Source and Contact: Philip White
Citizens' Nuclear Information Center
3F Kotobuki Bdg, 1-58-15, Higashi-Nakano, Nakano-ku, Tokyo 164-0003
Phone: 81-3-5330-9520
Fax: 81-3-5330-9530