Hong Kong’s government contacted the Nuclear Emergency Committee Office of Guangdong province on Tuesday amid reports of a radioactive gas leak at the Taishan nuclear plant.
Taishan, a Chinese-French 70-30% joint venture, is located about 140 kilometers west of Hong Kong.
Hong Kong Chief Executive Carrie Lam said her administration was highly concerned about the reports and added that the Observatory and Water Supplies Department had been closely monitoring local radiation levels but so far had not detected any abnormalities.
“As the Security Bureau said last night, everything is normal and in line with the relevant standards,” Lam said in a media briefing before the weekly Executive Council’s meeting.
She also said there was regular communication between the Hong Kong and Guangdong governments on nuclear safety issues, and that her government would keep the public informed of any new developments.
Beijing echoed Lam’s statement. “The Taishan nuclear power station has a good operating record … There is no abnormality in the radiation levels around the nuclear power plant and the safety is guaranteed,” foreign ministry spokesman Zhao Lijian said on Tuesday..
“China values nuclear safety highly and has established a nuclear safety regulatory system in line with international standards.”
On Monday, CNN reported that the US government was assessing a report of a potential noble gas leak at the Taishan nuclear plant, a modern fission reactor that commenced commercial operations in December 2018.
The report said French engineering company Framatome, a subsidiary of energy conglomerate Électricité de France (EDF) that operates and owns 30% of the reactor, sent letters to the US Department of Energy on June 3 and 8 to warn of an “imminent radiological threat.”
The letters reportedly claimed that China’s National Nuclear Safety Administration (NNSA) had revised up the acceptable limits for radiation levels outside the plant to prevent it from being shut down.
The letters also said the limit was now more than double than previously allowed and hence increased “off-site risk to the public and on-site workers.”
As of May 30, the Taishan reactor had reached 90% of the allegedly revised upward regulatory limit. However, the Joe Biden administration believed the facility was not yet at a “crisis level,” CNN reported citing an anonymous source.
Framatome said it was supporting the resolution of a “performance issue” at the plant related to the build-up of krypton and xenon that had affected the primary circuit of Taishan Unit 1.
However, it said the plant was operating within the safety parameters according to available data and that such gas build-ups were a “known phenomenon, studied and provided for in the reactor operating procedures.”
The remaining 70% of Taishan is owned by the state-owned Guangdong General Nuclear (GCN) Power Group.
“Our team is working with relevant experts to assess the situation and propose solutions to address any potential issue,” the French company said in a statement.
Framatome said it had requested to hold an extraordinary board meeting of the joint venture’s partners.
Reports said the French company, which has operations in the US, would need a US government waiver to help CGN fix the technological problems.
An unnamed spokesman for the plant told AFP that the noble gases had built up in part of the cooling system of Taishan’s Unit 1 reactor after the coating on some of the fuel rods deteriorated.
The spokesman said the gases that had built up in a component of the plant were collected and treated before being released into the atmosphere in “accordance with regulations.”
The spokesman added that the measurements of inert gases were below maximum levels authorized in China while it was too early to say whether the reactor would have to be shut down.
Prior to the CNN report, CGN released a statement on its website on Sunday evening that Taishan’s Unit 1 reactor, which commenced operation on December 13, 2018, had entered its second nuclear fuel cycle and was operating at full power.
It said its Unit 2 reactor, which started operation on September 7, 2019, had been overhauled as planned and was successfully connected to the grid on June 10, 2021.
It said the plant had fulfilled the safety requirements since the commencement of its operations. It also said the plant’s environmental indicators and its surroundings were normal.
CGN said in a press release on Monday that the plant’s workers and their children who resided near the nuclear facility were celebrating happily during an annual boat festival holiday.
Macau’s Unitary Police Service said Macao Meteorological and Geophysical Bureau’s gamma-ray monitor had not detected any abnormalities in the 24 hours as of 4 am on Tuesday.
On April 8, the Hong Kong government’s security bureau said it was informed by the Nuclear Emergency Committee Office of Guangdong province of an operational event at Taishan.
It said the monitoring system indicated that there was a short-term release of a very small amount of gas when the exhaust gas treatment system of Unit 1 of TNPS was performing a planned special operation on April 5.
It said the event was classified as a Level 0 deviation on April 6 and did not affect the safe operation of the unit, the health of the workers, the nearby public or the environment.
Prior to this, a Level 0 deviation was reported on February 21 due to a problem with the main water pumps in the coolant system at the same reactor. The two incidents were announced on CGN’s website but only in Chinese.
The recent increase in the concentration of certain noble gases in Unit 1 reactor suggested that fuel rods were leaking noble gases, a byproduct of nuclear fission, said Luk Bing-lam, chairman of the Hong Kong Nuclear Society and a senior engineer at the City University of Hong Kong.
The plant operators appeared to have managed the leak using normal procedures so far, Luk said.
“The plant operators normally extract the gases from the primary circuit, and then store it for a while to let the radiation level die down a bit…before releasing the gases to the atmosphere,” said Luk. “As a whole, that shouldn’t cause any major concern to the general public.”
However, Luk said the plant would have to suspend operations if the concentration of gases continued to accumulate.
He added that any threat arising from the reported incident had remained small to Hong Kong as the plant was more than 100 kilometers away from the territory.
The plant has a history of safety issues. When its construction started in 2009, the Taishan reactor was the first to deploy the French-designed Evolutionary Power Reactor (EPR) technology, which is also now used in France, Finland and Britain.
The technology, formerly known as a “European Pressurised Reactor”, is a “third-generation” nuclear technology that includes enhanced safety features as well as greater generation capacity. It was jointly designed by Framatome and Germany’s Siemens. Its third-generation rivals now include Westinghouse’s AP1000, Russia’s VVER-1200 and China’s Hualong One.
Framatome originally planned to have the world’s first ERP reactor commenced operation in Flamanville in France in 2014 but it delayed the launch to 2017 after some problems in the reactor pressure vessel were found. The debut was further postponed to 2023 as some pipes had to be repaired.
On December 12, 2017, Hong Kong’s FactWire reported that the component of a deaerator (a device that removes oxygen and other dissolved gases from liquids) at Taishan Unit 1 had cracked during testing.
On the following day, CGN Power Co, the Hong Kong-listed arm of CGN, said it had replaced the cracked component.
On December 29, 2017, the company said in a filing to the Hong Kong stock exchange that the expected commercial operation of Taishan Unit 1 would be delayed from the second half of 2017 to 2018 while that of Unit 2 would be postponed from the first half of 2018 to 2019.
On January 8, 2018, NNSA released a safety inspection report for the Unit 1 reactor of the Taishan plan and urged the plant to fix 20 minor defects in the facilities.
On January 9, Chinese President Xi Jinping and French President Emmanuel Macron met in the Great Hall of the People in Beijing and held an opening ceremony for the Unit 1 reactor in Taishan, which has become the world’s first ERP project.
On April 10, 2018, fuel assemblies were loaded into Unit 1’s core at the Taishan nuclear plant while its first chain reaction was attained in early June, according to EDF.