China Atomic Energy Authority, which oversees the development of nuclear energy in China, said fuel rod cladding failure is a common phenomenon in nuclear plant operations and is being dealt with in accordance with accepted standards and procedures.
The unit’s performance indicators, including the radioactivity of the primary reactor coolant, remain within the range of normal conditions and technical specifications, CAEA said.
It also said the reactor unit’s coolant system pressure boundary is intact and containment integrity maintained.
Environmental radiation monitoring has confirmed there has been no radiation release and there is no environmental concern, CAEA said.
According to the National Nuclear Safety Administration, the central government agency responsible for regulating nuclear safety, the specific radioactivity of the coolant in the reactor’s primary loop increased, but to levels that were still in accordance with safe operation.
The increased level of radioactivity in the primary circuit was mainly related to damaged fuel rod cladding, it confirmed. “Uncontrollable factors” including fuel manufacturing, transport and loading mean a small amount of fuel rod damage is unavoidable and is a common phenomenon.
There are more than 60,000 fuel rods in the Unit 1 core. The number of damaged fuel rod claddings is about five, less than 0.01% of the total, NNSA said. This is significantly lower than the maximum level of 0.25% allowed in the plant’s design parameters.
NNSA said there had been no leak of radioactivity into the environment. It also denied reports that a shutdown had only been avoided because it approved an increase in acceptable radiation limits outside the facility. “This report is not true,” a spokesperson said.
NNSA said it had reviewed and approved limits for activity of inert reactor coolant gas in the primary circuit. This was a revision to the technical specifications for chemistry and radiochemistry.
“This limit is used for operations management and is not related to the external radiation detection at the nuclear power plant,” NNSA said. “The concept described in the CNN report is wrong.”
The Taishan nuclear power station has two EPR nuclear power units, designed by France’s Framatome and constructed and operated as a Sino-French joint venture. Unit 1 entered commercial operation on 13 December 2018 and Unit 2 on 7 September 2019.
France’s state-owned EDF owns 30% of Taishan owner and operator TNPJVC in a joint-venture with China General Nuclear (CGN), which holds the remaining 70%.
EDF said earlier this week it had requested an extraordinary TNPJVC board of directors meeting for management to present “all the data and the necessary decisions”.
Framatome said it was supporting resolution of a performance issue at Taishan and according to the data available, the plant is operating within safety parameters.
French nuclear regulator ASN said it had proposed to the NNSA that the two regulators open a technical dialogue on the operating conditions at Taishan-1.