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Taishan EPR shuts down to repair damaged fuel rods
Regular readers will know that I am no fan of EDF’s third generation nuclear technology being deployed at Hinkley Point C – the European Pressurised Water Reactor (“EPR”). The company has been trying and failing to complete its flagship reactors at Flamanville and Olkiluoto with both schemes a decade late and something around three times over budget, and although two EPRs were completed at Taishan in China, the lack of transparency around costs and performance means they are rarely held up as genuine proofs of concept.
In my recent post about the troubles with the aging British nuclear fleet, there was some discussion about safety concerns at Taishan, and today has come an announcement that the plant has closed for urgent maintenance.
What is the problem at Taishan?
In mid-June reports began to emerge of a potential “imminent radiological event” at the Taishan Nuclear Power Plant in Guangdong Province, 80 miles from Hong Kong. Framatome, a subsidiary of EDF which holds a 30% stake in the plant had apparently informed US authorities on 8 June of a potential problem with a build-up of noble gases in the primary circuit of Taishan unit 1. The reason for the notification was that Framatome needed a US waiver in order to obtain the technical information required to solve the problem.
Responding to media reports of a leak at the plant China General Nuclear (“CGN”) announced on 13 June that Taishan 1 was operating at full power and there had been no release of radiation. However, Chinese safety authorities were reportedly raising the acceptable limits for radiation detection outside the plant in order to avoid having to shut it down, and did not publicly address the issue until 16 June.
The build-up of inert gases in the plant apparently occurred due to issues with the casing around some of the fuel rods, the first of three containment barriers at the reactor. On 16 June, China’s National Nuclear Safety Administration (“NNSA”) confirmed that the increase in the concentration of noble gases in the primary circuit was related to a few damaged fuel rods, stating that the plants performance was still in accordance with the requirements of its operating technical specifications. EDF announced the following day that this is “a known phenomenon, studied and provided for in the reactor operating procedures”.
“Due to the influence of uncontrollable factors such as fuel manufacturing, transportation, loading, etc, a small amount of fuel rod damage during the operation of nuclear power plants is unavoidable, which is a common phenomenon. According to relevant data, many nuclear power plants around the world have experienced fuel rod damage and have continued operating. Within the scope of allowing stable operation and meeting the requirements of technical specifications, the operational safety of nuclear power plants is guaranteed,” – NNSA spokesman
The NNSA estimates that of more than 60,000 fuel rods in the core of Taishan 1, about five probably have damage to their cladding, less than 0.01% of the total, and much lower than the maximum allowable damage to the fuel assembly of 0.25%. Nuclear fuel operates in a harsh environment in which high temperatures, chemical corrosion, radiation damage and physical stresses can undermine the integrity of the assembly.
The life of a fuel assembly in a reactor core is regulated to a burn-up level at which the risk of its failure remains low. Fuel “failure” in this context means a situation when the cladding has been breached, and radioactive material leaks from the fuel ceramic (pellet) into the reactor coolant water. The radioactive materials most likely leak through a cladding breach into the reactor coolant are fission-product gases and volatile elements, notably krypton, xenon, iodine and caesium.
Such fuel leaks do not present a significant risk to plant safety, although they can have a big impact on reactor operations and hence plant economics. Primary coolant water is continuously monitored so that any leak is quickly detected, and the permitted levels of released radioactivity are strictly regulated. The industry as a whole has made significant performance improvements in this respect, reducing fuel failure rates by about 60% in the 20 years to 2006 to an average of some 14 leaks per million rods loaded, according to the International Atomic Energy Agency.
An NNSA spokesman said that the increase in the level of radioactivity in the Taishan primary circuit is completely different from a radiological leakage accident:
“The primary circuit is inside the reactor containment. As long as the pressure boundary of the reactor coolant system as a radioactive containment barrier and the containment tightness meet the requirements, there is no possibility of radioactivity leaking to the environment.”
He also dismissed the reports that it had approved an increase in the acceptable limit of radiation detection outside the plant in order for it to continue operating, saying the regulator would continue to closely monitor the radioactivity level of the primary circuit of Taishan 1, strengthen on-site supervision and environmental monitoring; guide and supervise the operating units to take measures to strictly control the radioactivity level of the primary circuit, and strictly abide by the operation technical specifications to ensure that unit 1 runs safely.
However, last week EDF said it would have shut down the reactor if the facility were in France but that the decision to continue operating the plant was beyond its control.
“On the basis of the analyses carried out, EDF’s operating procedures for the French nuclear fleet would lead EDF, in France, to shut down the reactor in order to accurately assess the situation in progress and stop its development. In Taishan, the corresponding decisions belong to TNPJVC [Taishan Nuclear Power Joint Venture Co],” – EDF
EDF said it had been allowed to analyse data related to the “detection of unsealed assembly rods in reactor No 1 of the Taishan power plant” and that the data made available by CGN suggested the “radiochemical parameters” were still below regulatory thresholds in China, which were “consistent with international practices”. The company sought to play down the problem after a CNN report in June suggested the risk of a radiation leak, stating that a leak outside the facility is not a danger and the build-up of noble gases had been contained. A spokesperson for EDF told the FT last Thursday that the primary concern was to begin maintenance to resolve the issue:
“We want to prevent the fuel rods from deteriorating further, carry out investigations to figure out why the fuel rods lost their sealings, and we want the necessary maintenance to be as simple as possible. This is not an emergency or an incident. It is a situation, that is covered by operating procedures, that is known and understood.”
An extraordinary board meeting was held by the Taishan stakeholders last Thursday to review the latest data relating to the problem, and today it has been announced that the plant has now been shut down for maintenance to be carried out.
Role of China in British nuclear power
Separately from the problems at Taishan, there have been reports this week that the British Government is increasingly uneasy about the role of the Chinese in the British nuclear power sector. This follows the ban on equipment from Chinese telecoms manufacturer Huawei in the UK’s 5G network due in part to the impact of the National Intelligence Law in China which forces companies to comply with state intelligence work.
Aside from concerns the Government has over China’s current actions in Hong Kong and allegations of human rights abuse in Xinjiang, there is a growing concern over China’s involvement in strategic infrastructure when private companies can be compelled to hand over information about their activities in other countries.
Any decision to limit the role of Chinese companies in British nuclear power would affect the proposed second EPR at Sizewell C, and a new plant at Bradwell-on-Sea using Chinese nuclear technology (the Hualong One HPR1000 reactor) which is currently going through regulatory approvals process with a decision expected in the second quarter of next year.
The FT has reported this week that CGN “is likely” to walk away from the Hinkley Point C if the company is forced out of future projects in the UK. One nuclear industry executive reportedly warned that CGN could also reassess its involvement with Hinkley Point, pointing out there are four interlinked agreements between CGN, EDF and the government dating to 2015: Hinkley Point, Sizewell, Bradwell and the pursuit of regulatory approval for China’s reactor design, saying:
“Neither EDF nor the government can assume they can just deal with Sizewell in isolation. If you open one agreement then you potentially open all four. Legally, you open one part of the agreement, you run the risk of opening all parts of the agreement.”
But even without the emergence of geopolitical concerns, there are doubts over the economic viability of Sizewell C after HPC’s budget has soared from £14 billion to as much as £22.5 billion, risking its profitability. EDF’s final investment decision on HPC was marginal with one board member resigning over the issue so if CGN is barred from future projects and with HPC looking less attractive, the company may well be glad of an excuse to walk away.
Ministers would reportedly prefer a situation where CGN was replaced as a minority investor in Sizewell, but the deteriorating economics at HPC together with the ongoing problems with the EPR technology more broadly might make finding a new investor difficult.
In addition to strategic concerns, there are also worries around the lack of transparency from Chinese authorities. It took time for the details of the Taishan issue to be made public, and had the plant been wholly-owned by the Chinese, it’s doubtful that the situation would ever have entered the public domain, a situation reminiscent of the early days of the Chernobyl disaster where the Communist regime was slow to inform the public of the unfolding tragedy.
The language from EDF reported in the FT was also concerning, with its references to EDF having been “permitted” to inspect certain data which had been “made available”. This suggests that despite having a 30% stake in the plant, and partnering with CGN on its UK EPRs, EDF does not routinely have access to plant performance data at Taishan. If that is the case then it means that EDF is not able to benefit from any operational experience relating to what is an otherwise unproven technology, which does not bode well for its troubled European projects.
Unsurprisingly, none of this makes me more supportive of the EPR technology, and while I continue to believe that large-scale nuclear is essential to the British energy mix, I believe the most effective route would be to support the Wylfa Newydd ABWR scheme instead.