Mixed oxide (MOX) fuel combining plutonium and uranium has arrived at a Kansai Electric Power Co. nuclear power station in Fukui Prefecture, after a year-long delay caused by the French plant that made the fuel turning out a string of defective products.
A ship carrying the made-in-France MOX fuel docked at the Takahama nuclear plant in the town of Takahama on Nov. 22. It's planned to be used for pluthermal power generation in the station's No. 3 reactor.
Plutonium used for the fuel was extracted from spent uranium fuel from Kansai Electric's nuclear power plants by separating the substances at the Melox plant in southeastern France. In 2017, Kansai Electric ordered 32 MOX fuel assemblies, including the latest shipment. However, a streak of defective fuel assemblies in which the plutonium and uranium were not mixed evenly were found at the French plant. The first 16 assemblies arrived at the Takahama station in November 2021 for the use in the No. 4 reactor, but production of the remaining 16 was delayed, holding up final delivery for about a year.
This is the sixth MOX fuel delivery to the Takahama plant. The first batch arriving in October 1999 had been manufactured in the U.K., but it was later discovered that inspection data had been falsified, and the fuel was returned to the manufacturer unused. The fuel has been made by the Melox factory from the second batch onwards, but a series of defects have been reported. These defects are believed to be partially attributable to the technical complexity of MOX fuel production. A Kansai Electric official told the Mainichi Shimbun, "We've confirmed that the delivered assemblies fulfill a certain level of quality."
In Japan, no other power companies have plans to use MOX fuel by fiscal 2023. While Kansai Electric signed a contract in January 2020 to have another 32 MOX fuel assemblies manufactured at the French factory, the power company says the production or delivery dates remain "to be determined."
As of the end of December 2021, Japan had a stockpile of some 46 metric tons of plutonium, which can be used for nuclear weapons, and has promised the international community that it would not hold excess quantities of the radioactive element. But only so much plutonium will be used for pluthermal generation. While the nuclear reprocessing plant currently being built in Aomori Prefecture is planned to be used to chemically process spent nuclear fuel brought in from across Japan, some question this as it would increase Japan's plutonium reserve.
(Japanese original by Hidetoshi Ohshima, Expert Senior Writer at Osaka Editorial Division)