Operation of the mixed-oxide (MOX) fuel fabrication plant under construction in Rokkasho, in Aomori Prefecture, is now expected about two years later than previously planned. Japan Nuclear Fuel Limited (JNFL) had aimed to complete its construction in the first half of fiscal 2022 (ending March 2023), but now expects this in the first half of fiscal 2024.

The Nuclear Reprocessing Organisation of Japan (NuRO) requested JNFL to prepare a five-year provisional operation plan for the reprocessing plant and MOX fuel fabrication plant in order to consider a revision of its master plan (the medium-term implementation plan). JNFL has investigated the possible capacities of both plants from FY2021 to FY2025, and developed an operation plan.

Construction of the MOX plant began in late 2010. Construction of the 130 tonne per year plant had been delayed by three years from the planned 2007 start by the revision of seismic criteria following on from the powerful Niigata-Chuetsu-Oki earthquake.

Earlier this month, Japan's Nuclear Regulation Authority (NRA) approved the modification of safety measures at the Rokkasho MOX fuel fabrication plant. At the plant, work has been carried out to enhance the earthquake resistance of structures in operations rooms. Equipment to counter internal fires has also been installed. The plant floor space has been expanded in order to accommodate both these measures.

Construction of the Rokkasho reprocessing plant 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, according to JNFL.

Completion of both the reprocessing plant and the MOX fuel fabrication plant has faced several delays. Under the previous schedule, completion of the reprocessing plant had been put back to the first-half of FY2022, owing to the implementation of safety measures at the plant, including construction of a new cooling tower.

JNFL noted that as the final operation plan for the Rokkasho reprocessing plant and the MOX fuel fabrication plant will be finalised in NuRO's future master plan - which must be approved by the Minister of Economy, Trade and Industry - the plan it prepared is provisional.

Researched and written by World Nuclear News