Hongkong’s FactWire reported on 18 June that the EPR reactor at unit 1 of the delayed Taishan NPP in China’s Guangdong province, which achieved criticality on 6 June, had been started despite new problems identified by China’s National Nuclear Safety Administration (NNSA) one week earlier. The EPR (European Pressurised Reactor) is an evolutionary development of light water designs such the Framatome N4 and Siemens Power Generation Division KONVOI reactors. NNSA reportedly identified six major issues in Taishan 1 following a safety inspection in late May. It said that the operator, Taishan Nuclear Power Joint Venture, must rectify the problems before starting up the reactor. According to the report, the problems included equipment malfunction, such as failure of reactor monitoring systems, and human error in responding to false alarms.
NNSA called for ‘increased training for operating staff in order to minimise human error’, but did not mention how much time was supposedly required to resolve the issues. Factwire said it is unclear whether the company has already rectified the problems. This comes less than six months after an investigation by FactWire revealed cracks in important components of the same reactor, including a defective reactor vessel head that is set to remain in use for seven years.
In 2015, the reactor vessel heads at France’s Flamanville 3, another EPR, were found to have weak spots due to carbon concentrations that could weaken the resilience of the steel. The reactor was later ruled fit for service by French nuclear regulator ASN, but EDF, the owner of Flamanville 3 and also a minority partner in the Taishan project, was ordered to replace the vessel head by 2024. However, when the NNSA issued a fuel loading permit for Taishan 1 in April, it only required operator, plant operator China General Nuclear (CGN) to develop a testing method for its reactor vessel head “as soon as possible”, Factwire said. “If developments fail or test results are unfavourable, the cover shall not be used by the end of April 2025,” the permit reads.
Earlier in January, NNSA published an inspection report which listed 20 areas for improvement at Taishan, including “unclear roles and responsibilities” concerning fuel loading. Factwire noted that the report also pointed out that some pipelines required frequent repairs due to welding defects, for which the operator was only instructed to perform standard inspections and testing. Other problems identified in the report included wrong signage in the plant, lock failure in high radioactive areas, random reboots of the digital reactor monitoring system and incomplete training for nuclear fuel operators.
In December, FactWire revealed that a deaerator in Taishan unit 1 cracked during testing and must be replaced, as well as high carbon concentrations in upper head of a steam generator that had make them more prone to cracks. At the time CGN only admitted that there were ‘partial defects’ in the welding of the deaerator. CGN did not respond to FactWire’s enquiries regarding the start-up of Taishan unit 1, which is expected to enter commercial operation later this year, followed by unit 2 in 2019.
Taishan 1 and 2, the first two EPR reactors to be built in China, are part of an €8bn ($9.5bn) contract signed by Areva and China General Nuclear (CGN) in November 2007. The project is owned by the Guangdong Taishan Nuclear Power Joint Venture Company Limited, a joint venture between EDF (30%) and CGN. Construction of Taishan units 1 and 2, which began in 2009 and 2010, is five years behind schedule.
EPRs under construction in France and Finland are facing even longer delays. The first EPR to begin construction was at unit 3 of Finland's Olkiluoto NPP in August 2005 followed by another at unit 3 of France's Flamanville NPP in December 2007. Olkiluoto 3 almost a decade behind schedule, is only now undergoing fuel loading, while work on Flamanville 3 is on hold while welds are checked. Both projects have seen dramatic cost increases.