The Taishan nuclear power plant in China was placed under surveillance on Monday due to a sealing problem with its EPR nuclear reactor.
A decision that worries, after revelations from CNN on a possible radioactive leak within this reactor.
“20 Minutes” takes stock of what we know for the moment?
Since Monday, the first EPR reactor at the Taishan nuclear power plant in China has been under surveillance after the alert of a probable radioactive leak relayed by the American channel CNN.
A case that worries in a world still marked by Chernobyl and Fukushima, and which raises many mysteries and questions.
What is an EPR?
The Taishan nuclear power plant has two EPR reactors, “European Pressurized Reactors”, built by EDF. "These are the latest generation reactors, also called Generation 3, the most powerful in the world," informs Karine Herviou, Deputy Director General of the Institute for Radiation Protection and Nuclear Safety (IRSN). There are several reactors in operation and in start-up around the world, one in Finland and another in Flammanville.
But the Taishan reactors are the first to be commissioned and the only ones currently in operation.
“Reactor 1, also called the top of the series because it is the very first of this new model to have been started up, started up in December 2018, and is regularly shut down for unloading and refueling, it was shut down. 'last summer and is currently in the second cycle of operation,' says the expert.
What is going on in China?
Documents sent by Framatome, an EDF subsidiary which participated in the construction of these two EPRs, to the Biden administration report an "imminent radiological threat" and a possible "leak" in this plant, according to the authorities. CNN information.
Since then, the plant has been under surveillance for a leakage problem in the heart of a reactor.
EDF and the Chinese operator have nevertheless assured that the releases of radioactive gas into the air caused by this problem are within the authorized limits.
Where it becomes worrying is that Framatome would have indicated in the letter to the American authorities that China would have raised the acceptable limits of radiation outside the site to avoid having to shut down the plant.
What is a sealing problem in an EPR?
The reactor fuel is in the form of stacked pellets, surrounded by a metal cladding, which forms the first containment barrier (out of three in total). During the nuclear reaction, radioactive gases are believed to remain inside this sheath. "The Chinese operator has spotted an increase in activity of these gases in the cooling water, so there are ducts which are leaky and which allow these gases to pass", indicates Karine Herviou. These gases certainly end up in the interior duct, but will inevitably end up being released into the environment. They are normally treated to avoid too much radioactive release.
"These are rare gases such as krypton, xenon or argon, with a more or less long half-life," she continues. Normally, the power plants can operate up to a certain limit for the release of radioactive gases, beyond that, the procedure requires them to shut down the reactor. Each plant has an annual discharge authorization, and for the moment, Taishan would be below the authorized limits, knowing that Chinese standards are roughly in the international average.
“EDF has been informed of the increase in the concentration of certain rare gases in the primary circuit of reactor number 1 of the Taishan nuclear power plant owned and operated by TNPJVC, a joint venture of CGN (70%) and EDF (30% ) ”, EDF announced on Monday in a press release.
The gases were rejected "in compliance with the regulatory limits defined by the Chinese safety authority", specified the French group: "We are not on contaminations, we are on controlled, controlled releases.
What are the risks ?
Several voices want to be reassuring. China said there was no incident and the situation was under control. On the United States' side, "the Biden administration believes that the plant is not yet at a crisis level," said a government source quoted by CNN. The International Atomic Energy Agency (IAEA) has "no indication that a radiological incident has occurred."
The current elements therefore seem positive but they are dependent on the data provided. Which, in this specific case, is not trivial, as recalls Valérie Niquet, head of the Asia division at the Foundation for Strategic Research and author of the book
Chinese power in 100 questions
: “China is obsessed with its image of power, it boasted of its speed and efficiency in setting up these EPRs. If there is a problem, it is very likely that she seeks to minimize it, or that she does everything to prevent the shutdown of the reactor, which would sound like an admission of failure. "
At this time, there is no indication that China is trying to play down the problem.
If this were the case, and the leak level was too high, the reactor could become unstoppable.
Another problem is that the more gas accumulates, the more difficult it becomes to treat, and the more it is released with a high level of radioactivity in nature.
What role does nuclear play in Chinese energy?
China has around fifty operating nuclear reactors, which ranks it third in the world behind the United States and France.
Despite this place on the podium, “the share of nuclear power in energy is still minimal in China.
Between 4 and 6%, when the coal is still at 70% ”, indicates Valérie Niquet.
This low percentage is set to increase quickly, with China relying heavily on nuclear power to achieve these environmental and carbon-free energy goals.
“China is the country in which we build the most nuclear power plants, and which has the most in the pipeline.
International manufacturers have come to a halt in other countries after Fukushima, and China remains one of the only customers, ”continues Valérie Niquet.
For the time being.
China: An EPR nuclear reactor under surveillance after an increase in "rare gases"
Flamanville EPR: "There is no more margin" for start-up at the end of 2022, according to ASN