Fugen is a prototype Japanese nuclear test reactor that is currently shut down and awaiting Decommissioning. It is located in the Myōjin chō in the city of Tsuruga, Fukui. The design is an Advanced Thermal Reactor, which is a product of Japan. The name "Fugen" is derived from the Fugen Bosatsu (Samantabhadra) god in Buddhism.

The reactor was the first in the world to use a full MOX fuel core. It had 772 assemblies, the most in the world. It has received the title of a historic landmark from the American Nuclear Society.

The design boils ordinary water like a Boiling Water Reactor but uses heavy water as a moderator as in a CANDU reactor. The electrical output was 165 MW and the thermal output was 557 MW. On March 3, 2005 the reactor stopped operations.

Core temperature: 300 deg C Pellet centerline temperature: 2200 deg C Fuel conversion time: 6 months

Accidents

• 14. - 16 April 1997 a tritium leakage was announced to the responsible authorities 30 hours after the event. During the following investigation it was shown that it already had 11 similar incidents. Five managers of the operator at that time (at the time: Power Reactor and Nuclear Fuel Development Corporation) resigned.
• 8 April 2002 about 200 cubic meters of steam escaped from a defective pipe. The reactor was switched off.

Also with dismantling there were surprises: With controls it was stated that walls at 25 of 34 points did not have the necessary strength.

External links

• Fugen website