MOX fuel for Ohma

06 April 2009

The Japan Electric Power Development Co Ltd (J-Power) has signed an agreement with Global Nuclear Fuel Japan (GNF-J) for the supply of mixed-oxide (MOX) fuel assemblies for use in the Ohma nuclear power plant in Aomori Prefecture, Japan.

MOX (Melox)
MOX fuel assembly
(Image: Areva)
GNF-J has outsourced the manufacture of the MOX fuel assemblies to Areva's Melox subsidiary which will fabricate the fuel at Melox's plant in southern France, using Japanese plutonium recovered during the reprocessing of used fuel at Areva's La Hague plant.
Construction of the 1383 MWe Advanced Boiling Water Reactor (ABWR) at Ohma began in May 2008. The loading of the MOX fuel is scheduled to start in December 2013, ahead of the plant's planned start-up in November 2014.
J-Power plans to use all mixed oxide (MOX) uranium and plutonium nuclear fuel in the reactor core of Ohma, which necessitates some design variation from the ABWR standard. Amendments for the different reactive and thermal properties of MOX fuel include a higher-capacity liquid control injection system; additional safety valves to release steam; control rods with enhanced neutron absorption; and automatic fuel inspection devices to reduce radiation exposure to workers.
Apart from the Fugen experimental Advanced Thermal Reactor (ATR), Ohma would be the first Japanese reactor built to run solely on MOX fuel incorporating recycled plutonium. It will be able to consume a quarter of all domestically-produced MOX fuel and hence make a major contribution to Japan's 'pluthermal' policy of recycling plutonium recovered from used fuel.
The latest MOX contract with Areva comes as part of Japan's program to recycle used nuclear fuel and follows contracts signed in 2006 and 2008 with Japanese utilities Chubu, Kyushu, Shikoku and Kansai.
Japan's Federation of Electric Power Companies has said that all of its nine members would use plutonium as MOX fuel in 16-18 reactors from 2010 under the pluthermal program. About six tonnes of fissile plutonium per year is expected to be loaded into power reactors. Meanwhile, MOX fuel fabricated in Europe from some 40 tonnes of separated reactor-grade plutonium from Japanese used fuel can be used. However, local concerns about MOX fuel use slowed implementation of the 1994 pluthermal program.
Currently, MOX fuel is produced for Japanese nuclear operators in France and the UK. In future, Japan Nuclear Fuel Ltd (JNFL) will operate a used nuclear fuel reprocessing and recycling complex at Rokkasho, which will enable this to be done domestically.
MOX consists of a mix of uranium and plutonium oxides, recovered from used nuclear fuel. More than 30 power reactors in Belgium, France, Germany and Switzerland use MOX fuel, typically as one-third of their cores. Some units can use up to 50% MOX and some modern designs could use 100% MOX.