EDF experts provided technical details on the incident on EPR reactor No. 1 at the Taishan power plant on Monday June 14 in southwest China. A few hours earlier, the American television channel CNN reported that the American authorities had been warned of this malfunction on June 8 by Framatome, a subsidiary of EDF, and designer of this third-generation reactor, two of which have been in operation on the Chinese site since 2019.
“We are not on a dynamic of an accident with melting of the heart”, said a spokesperson for the French group, thus relativizing the seriousness of the problem, even if the Chinese operator had to “Achieve atmospheric emissions” rare gases “In compliance with the regulatory limits defined by the Chinese safety authority”. It is the fuel assembly cladding that is at the origin of the escape of xenon and krypton in the primary pressurized water circuit of the reactor building at the time of fission, he added.
The sealing problem appeared in October 2020, when the Taishan 1 reactor restarted after refueling, with uranium pellets embedded in the metal cladding. EDF indicates that at this stage, and given the information provided by its Chinese partners, “It is premature to say whether the reactor will have to be shut down to resolve the problem identified”.
” Manufacturing defect “
Such an incident has already occurred in France. “According to the operating rules, beyond a certain concentration threshold of these rare gases, the reactor must be shut down, recalls Karine Herviou, Deputy Director General of the Institute for Radiation Protection and Nuclear Safety (IRSN). We have no information regarding this threshold, and whether or not it has been reached. When this type of event happened in France, EDF had not reached the threshold set by the operating rules and had been able to wait until the end of the cycle to remove the defective rods. “
How to explain such an incident? “It may be due to a manufacturing defect in the sheaths or to “migrant bodies” (screws that move …), answers Mme Herviou. Obviously, as Taishan’s # 1 reactor is a seed [c’est même le premier EPR mis en service dans le monde], we will be following this very closely. ” The experience feedback should in particular benefit, according to her, the EPR of Flamanville (Manche), whose connection to the network is now scheduled for 2023.
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