There are likely five damaged fuel rods in the 1,750 MW Taishan-1 EPR in China, which have led to an increase in radiation levels within the reactor coolant, the Chinese Ministry of Ecology and Environment said in a statement June 16, providing the first official explanation for the nuclear reactor’s recent technical problems.

French power company EDF, a minority owner of the Taishan plant, said in a statement June 14 that Taishan-1 had seen an increase in the concentration of radioactive gases in its primary circuit.

The environment ministry added that “at present, the radiation activity of [Taishan-1’s] reactor circuit coolant … is still within the scope of allowing stable operation as stipulated in the technical specifications for the operation of the nuclear power plant.”

The meeting of technical specifications, which define the licensed operating parameters or a reactor, and operational safety of the Taishan plant are guaranteed, the ministry added.

It also said the increase in radioactivity in Taishan-1’s primary circuit is related to fuel-rod damage.

“Due to the influence of uncontrollable factors in fuel manufacturing, transportation, loading and so on, it is a common phenomenon that a small number of fuel rods are damaged in the operation of nuclear power units,” it said.

Taishan-1, which started commercial operation in December 2018, was the first EPR anywhere in the world to produce power. China has relied on a mix of foreign-designed and domestically developed reactors to deploy a fast-growing fleet of nuclear units.

The Taishan nuclear plant, located about 90 miles west of Hong Kong, is owned by TNPJVC, a joint venture between China General Nuclear, with a 51% stake, EDF with 30%, and Chinese power company Guangdong Energy Group, which holds 19%.

French NGO calls for halt to operations
Martial Chateau, a technical spokesman for French anti-nuclear non-governmental organization Sortir du Nucleaire, said June 16 that Taishan-1 should be shut because of the issues at the plant, noting that a reactor in France in similar circumstances would have stopped operating.

“We know there is a small crack in the tubes containing the fuel elements in the primary circuit. We don’t know what caused it. It could have been a foreign object like a screw or a bolt circulating in the water under pressure. Or it could be a design fault,” Chateau said. “There have been incidents like this in France.”

A Paris-based EDF spokesman told journalists June 14 that “at this stage, it is premature to talk about stopping the reactor to solve the problem that has been identified.”

EDF said in its June 14 statement that “as a shareholder of TNPJVC, [it] has requested the holding of an extraordinary TNPJVC board of directors meeting for management to present all the data and the necessary decisions.”

CGN, in a statement late June 13, said “at present, continuous monitoring of environmental data show that Taishan nuclear power plant and surrounding environmental indicators are normal.”

CGN also noted that Taishan-1 recently completed its second refueling outage and is now at full power. The unit connected to the grid from the most recent outage June 10, CGN said.

CGN added that “safety, quality, duration, and other indicators” during the outage were completed satisfactorily.

The permitted radiation level in coolant raised
The Chinese nuclear regulator, which is part of the environment ministry, noted in its statement that it had approved an increase in the radioactivity limits that applied to reactor coolant inert gases.

The regulator said a report on US television network CNN that the government had increased radiation limits outside the Taishan plant to avoid a shutdown of the unit was incorrect.

The incident has received significant media coverage, starting with the CNN report.

There are four EPRs under construction globally, including two at Hinkley Point C in western England, the long-delayed Olkiluoto-3 in Finland, and Flamanville-3 in northern France.

Chateau said technical problems at Taishan “are huge,” and could affect the ability of EDF, which owns the reactor’s supplier Framatome, to market the EPR design to countries such as India.

“If It emerges that there is a problem with the fuel ducts in the Taishan reactor and they have to be replaced it could mean closing the reactor for six months, if all goes well, and a year if it doesn’t,” he said.