French nuclear company Framatome, which helps operate the plant, last month reported a “performance issue” which caused the US government to look into the possibility of a leak.
“After lengthy conversations between French and Chinese technical personnel, Taishan Nuclear Power Plant ... decided to shut down Unit 1 for maintenance,” China General Nuclear Power Group (CGN) said on Friday in an online statement, adding that “a small amount of fuel damage” occurred during the operation of the reactor.
CGN said that both units of the plant had “maintained safe and stable operations throughout” and the faulty reactor was “completely under control”. The company said there had been “minor fuel damage” and the reactor was shut down for maintenance and to replace damaged fuel.
Engineers would now “find the cause of fuel damage and replace the damaged fuel”, the statement added.
China’s regulator said last month that of the more than 60,000 fuel rods in the Unit 1 core, the number of damaged fuel rod claddings is about five, less than 0.01% of the total. This is significantly lower than the maximum level of 0.25% allowed in the plant’s design parameters.
Plant supplier EDF said last month that a build-up of noble, or inert, gases at the 1,660-MW EPR unit seemed to have occurred because of issues with the casing around some fuel rods.
EDF said it would have shut down the reactor if the facility were in France, but that the decision to continue operating the joint venture was beyond its control.
Taishan-1 was the first EPR unit to begin commercial operation, in December 2018. The technology was designed and developed mainly by Framatome (part of Areva between 2001 and 2017) and EDF in France, and Siemens in Germany. A second EPR at Taishan began commercial operation in September 2019.
