France’s Nuclear Safety Authority has ordered the country’s EDF utility to conduct checkups at five nuclear reactors ahead of their scheduled maintenance tests, citing potential weakness in critical parts manufactured by a Japanese company, French media reported Tuesday.
All five nuclear reactors are using parts made by Kitakyushu-based Japan Casting & Forging Corp. (JCFC), which is now under scrutiny by Japan’s Nuclear Regulation Authority.
The NRA discussed the matter at its regular meeting on Wednesday as it has also found the company manufactured reactor pressure vessels in 13 Japanese nuclear reactors including the Sendai Nos. 1 and 2 reactors operated by Kyushu Electric Power Co. in Kagoshima Prefecture.
The Sendai No. 1 reactor is undergoing a regular checkup while the No. 2 reactor is in operation.
In addition, the NRA said JCFC had been manufacturing important components at the No. 2 unit at Kansai Electric Power Co.’s Mihama plant in Fukui Prefecture and No. 1 unit at Kyushu Electric Power Co.’s Genkai nuclear plant in Saga Prefecture, which have already been decommissioned.
The French nuclear watchdog ASN said earlier in June that parts manufactured by JCFC using a method called “forging,” in which metals are hammered and extended, contained a high carbon concentration that could lead to lower-than-expected mechanical strength.
In the documents submitted to the NRA meeting, JCFC admitted there is a possibility that the parts used in nuclear power plants in France contain carbon higher than the regulated limits, but parts used in Japan are manufactured after removing high-carbon concentration from steel.
According to the media reports, safety tests have already been carried out at seven of a total of 12 reactors in France that used parts manufactured by JCFC. Parts at four of the seven reactors are believed to contain a higher carbon concentration than permitted by standards.
Following these findings, ASN told EDF to test the remaining five reactors within three months.
France has 58 commercial nuclear reactors. At the No. 3 reactor at Flamanville nuclear plant, which is under construction, parts made in 2014 by Creusot Forge, a subsidiary of France’s Areva SA, were found to be lacking in strength. ASN later discovered that the parts manufactured by JCFC also had problems.