Japanese utilities revise MOX utilisation plan

26 February 2021

A revised mixed oxide (MOX) fuel utilisation plan, based on the latest operational plan for the Rokkasho Reprocessing Plant and the MOX Fuel Fabrication Plant, has been released by Japan's Federation of Electric Power Companies (FEPC). While only four Japanese reactors have so far been restarted using MOX fuel, FEPC envisages at least 12 units running on the fuel by FY2030. FEPC represents the 11 power companies, comprising nine utilities (excluding Okinawa Electric Power), Japan Atomic Power Company and the Electric Power Development Company (J-Power).

Takahama unit 3 and 4 have been using MOX fuel since being restarted (Image: Kansai Electric Power Company)

As long ago as the 1950s, Japanese nuclear energy policy recognised that the energy resource-poor country must recycle uranium and plutonium recovered from used nuclear fuel. 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 the full-scale operation of its own reprocessing and MOX fabrication facilities.

"In Japan, where resources are scarce, we will secure stable energy in the future," FEPC said today. "In order to do so, it is essential to establish a nuclear fuel cycle in Japan. Even in the midst of changes in the environment surrounding nuclear power generation after the accident at the Fukushima Daiichi power plant, the importance of pluthermal [MOX] fuel does not change."

Construction of a reprocessing plant at Rokkasho began in 1993 and was originally expected to be completed by 1997. The facility is based on the same technology as Orano's La Hague plant in France. Once operational, the maximum reprocessing capacity of the Rokkasho plant will be 800 tonnes per year. Construction of a 130 tonne per year MOX plant, also at Rokkasho, began in late 2010.

However, completion of both the reprocessing plant and the MOX fuel fabrication plant has faced several delays. In December last year, Japan Nuclear Fuel Limited said it now expects to complete construction of the reprocessing plant in 2022 and that of the MOX fuel plant in 2024.

Since the March 2011 accident at the Fukushima Daiichi plant, four reactors - Genkai 3, Ikata 3 and Takahama 3 and 4 - have resumed operation using MOX fuel. FEPC estimates that these units will use a total of 0.2 tonnes of plutonium in 2021, 0.7 tonnes in 2022 and 1.4 tonnes in 2023. These usage amounts are based on the operation plan of each company, as of January this year, FEPC noted.

It said the operation plan for 2024 and beyond is undecided, but from the perspective of showing the outlook for plutonium usage after the start of operations at the Rokkasho reprocessing plant, the current outlook for usage is: 0.7 tonnes in 2024; 1.4-2.8 tonnes in 2025; and about 6.6 tonnes annually between 2026 and 2030.

The start of use of domestically-produced MOX fuel is expected to be after 2026, FEPC said.

On 17 December, FEPC said it had been "continuing to work diligently through promoting pluthermal to establish the nuclear fuel cycle as a critical task".

It said the power companies it represents had decided to follow the measures "as our new pluthermal programme in order to manage plutonium stockpiles appropriately on the premise that each utility is responsible for using its own plutonium".

With the consent of the local community, the utilities agreed to examine the possibility of introducing MOX fuel to as many operating reactors as possible as part of a mid to long-term plan and will do their utmost efforts to ensure a balance between demand and supply of plutonium.

The utilities aim to have at least 12 reactors utilising MOX fuel by FY2030. They also agreed to promote using plutonium and reduce the size of their stockpiles at home and abroad through close collaboration and cooperation among the utilities.

Researched and written by World Nuclear News