Monju to return in 2008 with new plutonium core

Thursday, 17 January 2008 Japan's Monju fast breeder reactor should return to service this year, with fresh plutonium fuel replacing its initial core load. 

A safety review is currently underway concerning replacing the reactor's current fuel load. During the 12 years that Monju has been offline, enough plutonium-241 in the inner core has transmuted to americium-241 to cause a deterioration in the level of reactor response, according to an Atoms in Japan report.

The 280 MWe fast breeder prototype reactor was built and operated by the Japan Atomic Energy Agency. It started up in April 1994, but a sodium leak during performance tests has seen it out of action ever since.

The restart of Monju is a key aim in Japan's national nuclear program, which foresees the FBRs expected to follow Monju becoming the main nuclear power systems of the 21st century. Japan is also a member of the Generation IV International Forum, a group of nations investigating advanced nuclear energy systems - including several FBR designs - for use after 2030.

Design changes necessary to improve Monju's safety were made between September 2005 and May 2007, with verification tests starting in August 2007 and set to finish in August this year. About one quarter of the required verification tests have been carried out to date.