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Taishan Problems An investigation is still under way into leaks at nuclear power plant.

The second EPR reactor at China’s Taishan nuclear power plant is about to enter into commercial operation.

  nuClear News No 136 Dec 21, Taishan Problems An investigation is still under way into the cause of problems at the Chinese EPR plant in Taishan. It was shut down in August after reports of damage to fuel rods. The plant is operated by CGN and owned in partnership with EDF, the two companies involved in building Hinkley Point C (HPC). 

The Times (1) has reported that key safety components at HPC may need to be redesigned and the project delayed after defects were detected at a similar reactor in China. The newspaper says the scheduled start date for electricity generation, of June 2026, may have to be postponed.

The Commission for Independent Research and Information on Radioactivity (CRIIRAD), a French association created in the aftermath of the Chernobyl disaster, said that a whistleblower had reported to them that a design flaw in the reactor pressure vessel could be the cause of the problem at Taishan which means that design changes may be needed. 
In a letter to the French nuclear regulator (2), ASN, CRIIRAD says: “In June 2021, the national and international press widely covered the case of the problems of ruptured nuclear fuel cladding at the Taishan 1 EPR reactor in China.”   

  It goes on to say there are several possible causes of the rupture some of which may involve design flaws in the reactor. A whistleblower has now told CRIIRAD that the ruptures are caused by a design flaw in the reactors pressure vessel. This will also cause problems in other EPR reactors like Hinkley Point C.

The letter continues: “If they are true, these revelations raise serious questions in terms of nuclear safety and radiation protection, both for plant workers and for residents. The existence of a generic design defect on the EPR reactor vessel could jeopardize the start-up of [other EPR reactors].”   

  Stop Hinkley spokesperson, Roy Pumfrey says:
 “What’s been cobbled together to get Taishan started clearly isn’t working. It’s just another example of the folly of complex designs for big new nuclear reactors. Trying to identify and correct the design flaw can only lead to further delays and cost overruns for the absurdly expensive HPC project.” 

“Stop Hinkley will be pressing the UK’s Office of Nuclear Regulation for a full disclosure of its investigations into this matter. And if there are expensive delays and modifications to HPC required, given the already huge cost to consumers, we will be asking government officials to investigate whether, in fact, it would be cheaper to cancel the whole thing.”   

Eva Stegen, German blogger and energy consultant says the whistleblower gave the radiation research institute ‘CRIIRAD’ important detailed technical information from Taishan. With every additional day on which neither the operator nor the French nuclear regulatory authority – ASN – deny, the hypothesis that the design error affects all EPRs, Taishan’s problems become more  important. She reminds us that in June 2021, a ‘CNN’ report from Taishan, China caused a stir. There was talk of an “immediate radiological threat” in a letter from the French consortium partner “Framatome” to the US Department of Energy. The Chinese security authorities were accused of having raised the radiation limit values for the outside area around the nuclear power plant in order to circumvent the shutdown of the defective reactor block.

 In this context, a little-noticed communication of the Institute for Radiation Protection and Nuclear Safety – IRSN – of March 31 assumes new significance: the Institute expressed concern about “abnormally high vibrations” already observed in the primary circuit of several EPR reactors. It said the overall architecture of the primary circuit piping leads to the severe vibrations in the reactor pressure vessel due to an unfavourable distribution of the cooling water. These vibrations could lead to a pipe rupture in the primary circuit and cause significant radioactive releases. This raises the question whether the entire piping architecture should not be revised  

As early as 2018, the Finnish power utility ‘TVO’ and the Finnish safety authority ‘STUK’ reported that during tests at Olkiluoto, vibrations had occurred in the primary circuit at the reactor pressure vessel. 

So along with carbon-brittle misfits, botched welds and inferior concrete comes the vibration problem. The once-vaunted core catcher, which was supposed to be used to contain a melted reactor core, is apparently also giving engineers a headache. If a major fragment of the vessel were to block the chute to the catcher, the corium would not flow into the catcher. (3)

December 11, 2021 - Posted by | China, safety

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