NRA approves Japan’s mox plant at Rokkasho

11 December 2020

Japan’s mixed-oxide (J-MOX) fuel plant under construction in Rokkasho, Aomori Prefecture, received Nuclear Regulation Authority (NRA) approval on 9 December, despite the lack of a concrete plans for the use of mox in future.

Currently only four reactors in Japan use mox and there are no plans for additional plants.

At the December meeting, the five NRA commissioners, including Chairman Toyoshi Fuketa, all approved the safety measures taken at Rokkasho, which included separating nuclear materials, improving earthquake resistance and installing fire control equipment.

The government and the power industry have promoted the use of mox fuel for decades on the grounds that fuel recycling is essential for resource-poor Japan and will help to reduce its stockpile of plutonium. Japan Nuclear Fuels Ltd (JNFL) applied for safety checks with the NRA for the plant in January 2014 to meet the stricter regulations imposed following the 2011 Fukushima accident.

It had initially planned to complete the Rokkasho plant in 2012 but the date was postponed repeatedly due to work suspensions following the Fukushima crisis. This was just the most recent in a series of delays. Construction of the the 130 tonne-a-year J-MOX plant had begun in 2010 after it  had been delayed by three years by revision of seismic criteria in the aftermath of the Niigata-Chuetsu-Oki earthquake.

The plant still needs to pass further checks on its construction plans before it can start operations, raising doubts that the facility can be completed by the first half of the fiscal year starting April 2022 as sought by JNFL. Construction costs have rocketed from the initial JPY120 billion ($1.15 billion) to JPY390 billion. Total expenses, including outlays to run the plant, are expected to reach JPY2340bn.

JNFL is also facing delays with its reprocessing plant, also under construction at Rokkasho. In July, NRA gave permission for the modification of safety measures at the plant. Additional equipment and systems are being installed for the recovery of radioactivity in the event of a severe accident. Other safety-related countermeasures are also being put in place, such as internal flood protection, strengthening of the seismic resistance of pipework and improving measures against internal fires.

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 and will have a capacity of 800 tonnes a year, according to JNFL.

Under the latest schedule, completion of the reprocessing plant has been put back to the first-half of FY2022 (ending March 2023), to allow for implementation of safety measures at the plant, including construction of a new cooling tower.


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