Preparations for Japan's first use of MOX

01 October 2009

An earlier version of this story stated that MOX loading was scheduled for 3 October, but this date had in fact been revised by Kyushu Electric Power Company. WNN apologises for this error.


The loading of mixed-oxide (MOX) fuel into the third reactor of the Genkai nuclear power plant in Japan has been postponed, putting back the first ever use of the fuel in the country. 


Genkai (Kyushu)
The Genkai plant (Image: Kyushu)
Fuel loading had been slated for 3 October, but this has now been dropped after an objection from the local parliament with no new date yet announced.


About 5% of the content of MOX fuel is plutonium recovered from nuclear fuel already used in power-generating reactors. Recycling the material in this way increases the energy it produces by 12%, while if unfissioned uranium is also recovered and reused the figure increases to 22%. The process also allows the separation of the most highly radioactive fission products, meaning the volume of the most dangerous waste is reduced by over 60%.


This kind of recycling is to be the basis of Japan's future nuclear fuel cycle, so that the resource-poor but energy-hungry country can get the best value from imported uranium. Later steps are planned to include fast neutron reactors to use more plutonium and generate more fissionable fuel with nuclear power providing over 40% of electricity.


Plant owner Kyushu Electric Power Comapany signed a contract with Mitsubishi Heavy Industries (MHI) in September 2006 for the supply of MOX fuel for Genkai unit 3 - a 1127 MWe pressurized water reactor that began operating in 1994. MHI then subcontracted the manufacture of the fuel to France's Areva, which made the fuel at its Melox plant. Genkai took delivery of the first 16 MOX assemblies in May this year and plans to increase the number in use to 48 of the total of 193 assemblies in the core. Production of a further 20 MOX assemblies began at the Melox plant in early June.


Up until 1998, Japan sent the bulk of its used fuel to plants in France and the UK for reprocessing and MOX fabrication. However, since 1999 it has been storing used fuel in anticipation of full-scale operation of its own reprocessing and MOX fabrication facilities.


In June, Japan's Federation of Electric Power Companies (Fepco) announced the country's plans for MOX fuel use had been revised. Fepco chairman Shosuke Mori said that, after reviewing the organisation's so-called 'Pluthermal' project in the light of national policy and the availability of the country's own reprocessing facilities, it had been decided to revise its goal of having 16-18 reactors using MOX fuel to fiscal 2015 instead of 2010.


Japan Nuclear Fuel Ltd's (JNFL's) reprocessing plant under construction at Rokkasho is scheduled for completion in August 2009, but earlier this year the company put back the completion date for its planned J-MOX fabrication facility from August 2012 to August 2015. Construction work on the fabrication facility is scheduled to begin in November 2009.


While waiting for domestic facilities to become available, Japanese utilities have been signing overseas contracts to meet their MOX requirements. Global Nuclear Fuel-Japan (GNF-J) has outsourced a contract to manufacture the first three years' worth of fuel for J-Power's new Ohma ABWR plant, designed to run on a full MOX core, to Areva. The French company also has MOX fabrication contracts with Chubu, Kyushu, Shikoku and Kansai.