China environment ministry says no leak at Taishan nuclear power station

China's environment ministry said on Wednesday that there was no leak at the Taishan nuclear power station, responding to a CNN report earlier this week.

The Ministry of Ecology and Environment also said in a statement on its official WeChat account that the National Nuclear Safety Administration did not raise acceptable limits for radiation detection levels outside of the Taishan plant.

Earlier, a US media report had revealed the possibility of a potential leak in a Chinese nuclear plant near Hong Kong after its French operator said that the plant is dealing with a 'performance issue' linked to a gas build-up.

The Taishan Nuclear Power Plant is jointly owned by China Guangdong Nuclear Power Group and French multinational electric utility Électricité de France, the main owner of Framotome, which helps operate the plant.

CNN reported that Framotome had written to the US Department of Energy warning of an 'imminent radiological threat' and accusing Chinese authorities of raising acceptable limits for radiation outside the plant to avoid having to shut it down.

EDF, the majority owner of Framatome, said in a statement that it had requested an extraordinary meeting of the power plant's board 'for management to present all the data and the necessary decisions'.

Framatome said in a statement that it is 'supporting a resolution of a performance issue' at the plant.

"According to the data available, the plant is operating within the safety parameters," the company said.

EDF later said that there was an "increase in the concentration of certain noble gases in the primary circuit of reactor no. 1" at Taishan, referring to a part of the reactor's cooling system.

Noble gases are elements like argon, helium and neon which have low chemical reactivity.

Their presence in the system "is a known phenomenon, studied and provided for in the reactor operating procedures," EDF said.

David Fishman, manager at energy-focused consulting group The Lantau Group, said that the presence of noble gases could suggest the problem was caused by a cracked fuel rod.

"When you have a cracked fuel rod... you get a small release potentially of fission materials from inside that cracked fuel rod into the cooling loop, where it wouldn't normally be," he said. 

"Failed fuel or cracked fuel is a fairly normal and common, undesirably certainly but not uncommon phenomenon in the nuclear fuel industry."

Citing a letter from Framatome to the US energy department, CNN said the warning included an accusation that the Chinese safety authority was raising the acceptable limits for radiation outside the facility in order to avoid having to shut it down.

But a US official told the broadcaster that the administration of President Joe Biden believes the facility is not yet at "crisis level".

The operator of the power station, state-owned China General Nuclear Power Group (CGN), said in a statement on Sunday evening that "the environmental indicators of Taishan Nuclear Power Plant and its surroundings are normal".

It did not reference any leak or incident at the power station, which it said meets "the requirements of nuclear safety regulations and power plant technical specifications."

The International Atomic Energy Agency, a UN body, said it had contacted its counterpart in China regarding the issue.

"At this stage, the Agency has no indication that a radiological incident occurred," the IAEA said in a statement, adding that it would share more information "as it becomes available".

If the problem is a cracked fuel rod, said Fishman, it would have to be logged by the Chinese nuclear safety administration with a mitigation report to fix the problem.

What's more, "if (Framatome) were going to transfer over any information that they have gotten from working in the US, they would have to apply for an exemption... because CGN is on the US entity list," he added.

"It is a no-fly zone for any US information, any information or data or technology or IP to go to China."

(With inputs from agencies)