Originally published 2021-06-15.
In June 2021 the United States looked into a reported leak at the Taishan nuclear power plant in China's Guangdong province, about 130 km west of Hong Kong. The alarm came from Framatome, the French company that helps run the plant, which told the US Department of Energy of an "imminent radiological threat." What turned out to be happening was serious but far from a disaster: some fuel rods in reactor unit 1 had damaged cladding, letting radioactive noble gases build up inside the reactor's sealed cooling circuit. China said radiation around the plant stayed normal, and unit 1 was shut down at the end of July 2021 for repairs.
The story briefly sparked fears of a Chinese Chernobyl. Looking back, it is a useful case study in how a technical problem, an unusual legal request and a lack of transparency can turn into alarming headlines.
What Framatome told Washington
On 14 June 2021 CNN reported that Framatome, a subsidiary of the French energy group EDF, had written to the US Department of Energy earlier that month. A memo dated 8 June asked for an expedited review, describing the problem in strong language and saying the plant was leaking fission gas.
The reason for the letter was legal as much as technical. US export rules restrict the sharing of American nuclear technology and expertise with China. Framatome wanted a waiver so it could pass on US technical help to fix the problem, and such a waiver can be granted in only two situations, one of them an imminent radiological threat. That helps explain why the phrase appeared in the request.
The memo also claimed that China's regulator, the National Nuclear Safety Administration, had raised the acceptable limit for radiation detected outside the plant to more than double the original level, which had matched French standards, so the plant would not have to shut down. According to CNN, US officials at the time judged the situation not to be at crisis level but worth monitoring.
What was actually going wrong
Inside a reactor, uranium fuel pellets are sealed in long metal tubes called fuel rods. Splitting uranium atoms creates fission products, including the noble gases xenon and krypton. If a rod's thin metal cladding cracks or wears through, some of those gases escape into the primary circuit, the closed loop of water that carries heat away from the core.
That is what Framatome and EDF described at Taishan unit 1: rising levels of noble gases in the primary circuit, caused by a small number of failed rods. Gases in the primary circuit are not the same as a release to the outside world. The circuit is sealed, and gas removed from it is processed and held before any controlled discharge. Plants around the world deal with occasional leaky rods, and operating rules set limits for how much activity is allowed before a reactor must stop.
China's regulator had separately reported an unexpected release of radioactive gas at unit 1 on 5 April 2021, calculated at a tiny fraction of the plant's annual limit, about 0.00044%.
How China and EDF responded
China General Nuclear Power Group (CGN), which owns 70% of the plant, insisted that environmental readings at Taishan and the surrounding area were normal and that the plant met safety requirements. China's regulator said the number of damaged rods was within the limits allowed in the plant's technical specifications and rejected suggestions of a dangerous release.
EDF, which holds the remaining 30%, took a noticeably different tone. It confirmed the noble gas problem and later said that, in France, a reactor in that condition would already have been shut down.
On 30 July 2021 CGN announced that unit 1 had been taken offline for maintenance to find and replace the damaged fuel. CNN reported that fewer than 0.01% of the reactor's more than 60,000 fuel rods were affected. The reactor stayed offline for about a year and was reconnected to the grid on 15 August 2022.
Why the Taishan reactors are special
Taishan is home to the world's first two operating EPRs, a large French-designed pressurised water reactor model with a nameplate capacity of about 1,750 megawatts each. Unit 1 entered commercial service in December 2018 and unit 2 in September 2019, beating the EPRs under construction in Finland and France, which suffered long delays and budget overruns.
That made the plant a showcase for the design, and it is one reason the 2021 problem drew so much attention in Europe. Later reports linked the fuel damage to vibration of fuel assemblies, reportedly connected to coolant flow at the bottom of the reactor vessel, an issue EDF said it would study for its own EPRs.
Myths that spread during the scare
- "A nuclear disaster is unfolding near Hong Kong." No measurement made public showed elevated radiation in Hong Kong or Guangdong.
- "The plant had been leaking radioactive gas into the air for weeks." The leak was of fission gases into the sealed reactor circuit. A small, regulated release in April was reported at a minute fraction of the limit.
- "Covid lockdowns were a cover for radiation." Some social media posts linked local pandemic restrictions to the plant. There was no evidence for this.
The fair criticism is about openness rather than danger. Much of what the public learned came from a leaked memo, and Chinese authorities gave few details until the shutdown. That gap is what allowed speculation to grow.
China's nuclear programme in context
Taishan is one piece of a fast-growing nuclear fleet. China had about 50 reactors in operation in 2021, generating roughly 5% of its electricity, and that year it overtook France to become the world's second-largest producer of nuclear power after the United States, according to IAEA figures. By late 2026 the country had more than 60 operating reactors and many more under construction.
Beijing sees nuclear power as part of its plan to peak carbon dioxide emissions before 2030 and reach carbon neutrality by 2060, because reactors produce very little carbon once running. China builds mostly domestic designs but has also bought from abroad, including French EPRs at Taishan and Russian VVER reactors at Tianwan and Xudabao, under a 2019 contract for four more Russian-designed units.
The Taishan episode showed that even a modern plant can develop fuel problems, and that safety depends as much on clear, timely information as on engineering.
Sources: CNN via KTVZ, 14 June 2021; CNN, 31 July 2021; Wikipedia, Taishan Nuclear Power Plant; Wikipedia, Nuclear power in China; originally reported by Daily Mail.
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