Fugen ふげん (Fugen) was a prototype Japanese nuclear test reactor. Fugen was a domestic Japanese design for a demonstration Advanced Thermal Reactor. It was a heavy water moderated, boiling light water cooled reactor.[1]The reactor was started in 1979 and shut down in 2003. As of 2018, it is undergoing decommissioning.[1]It is located in Myōjin-chō, in the city of Tsuruga, Fukui. The name "Fugen" is derived from Fugen Bosatsu (Samantabhadra), a Buddhist deity.
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 (BWR) 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.
The plant is located on a site that covers 267,694 m2 (66 acres); buildings occupy 7,762 m2 (1.9 acres), and it has 46,488 m2 of floor space. It employed 256 workers.[2]
During dismantling operations it was found that walls with controls did not have the necessary strength at 25 of 34 points.
