What is happening at the Taishan nuclear power plant in southern China?
Framatome, a subsidiary of EDF which takes care of the management of this plant, alerted the United States last week for technical assistance, citing an "imminent radiological threat" and a radioactive leak, according to CNN.
Framatome simply indicates, in a press release, to monitor "the evolution of one of the operating parameters" of the nuclear power plant.
What is happening in the plant?
Radioactive gases are escaping from the Taishan nuclear power plant, according to documents sent by Framatome to the United States and of which CNN was able to obtain a copy.
"If they have a gas leak, this indicates that part of their containment is broken," testifies to the American channel a retired nuclear scientist.
Little information is available as to the nature and extent of this leak.
The Chinese operator of the nuclear power plant denied on Monday the existence of any problem.
"At present, continuous monitoring of environmental data shows that the environmental indicators of the Taishan nuclear power plant and its surroundings are normal," he said.
According to CNN, if the situation deserves to be "watched", the leak would not be at a "crisis level" according to US officials. The United States, still according to CNN, believe that there is for the moment nothing to fear for the workers of the plant or the inhabitants.
"EDF has been informed of the increase in the concentration of certain rare gases in the primary circuit of reactor No. 1 of the Taishan nuclear power plant," the French group said on Monday, not to mention a leak.
The primary circuit is a closed circuit containing pressurized water, which heats up in the reactor vessel in contact with the fuel elements.
So-called "rare" gases include argon, helium, krypton, neon or even xenon.
"The presence of certain rare gases in the primary circuit is a known phenomenon, studied and foreseen by the operating procedures of the reactors", adds EDF.
Why did Framatome warn the United States?
Framatome, an EDF subsidiary, designs nuclear power plants and then takes care of their maintenance.
She was behind the design of the Taishan nuclear power plant.
If it alerted the United States (without knowing whether it alerted France before), it is because Framatome considers the situation critical to the point of asking for intervention.
"Framatome is urgently requesting authorization to transfer the technical data and assistance which may be necessary to put the plant back into normal operation," wrote the French company in its letter to the US Department of Energy.
Framatome does not seem to find much echo in China: the government agency reduces the standards there in order to allow the plant to remain open… even if there is a leak.
After the alert in the United States, exchanges took place, according to CNN, with the French authorities.
In France, the Commissariat for Atomic Energy and Alternative Energies (CEA) and the Nuclear Safety Authority (ASN) had not yet commented on Monday morning.
EDF says it has contacted the TNPJVC joint venture, which operates the nuclear power plant, and "brings its expertise".
The French group also says it has "requested the holding of an extraordinary board of directors of TPNJVC so that the management presents all the data and the necessary decisions".
The EPR involved?
The Taishan nuclear power plant is equipped with two EPRs (for European Pressurized Reactor).
Several are under construction, in Finland, the United Kingdom and in Flamanville (Manche), in France.
Others are in the pipeline.
The Taishan EPRs were the first to be put into service, in 2018 and 2019, for the time being in the world, and remain the only ones currently in operation.
For now, we do not know if it is the EPR model, a construction or operational problem that explains this possible leak.
In its press release on Monday, Framatome (also responsible for the construction of EPRs) said it was monitoring "the evolution of one of the operating parameters".