ENERGY

Chinese nuclear reactors ‘did not receive latest safety tests before installation’

French manufacturer said recent test detected fault that could lead to cracks in reactor shell

PUBLISHED : Friday, 10 April, 2015, 5:18pm
UPDATED : Wednesday, 15 April, 2015, 3:30pm

Two new nuclear reactors in Taishan, Guangdong, did not undergo the same quality tests as a similar reactor in France that was found to have weak spots prone to cracks.

Special tests at the Flamanville EPR nuclear power plant were only carried out last year after France tightened its nuclear safety regulations, France’s Nuclear Safety Authority (ASN) told the South China Morning Post.

No such tests were conducted on the two third-generation EPR Taishan reactors before French nuclear manufacturer Areva shipped them to China.

That meant the 50-billion yuan (HK$63 billion) Taishan plant, located about 80km west of Zhuhai and Macau, could be plagued by the same problem and not be detected.

Weak spots in a reactor’s steel shell is a serious defect – once installed, the shell cannot be replaced throughout the reactor’s 60-year lifespan.

The tests in France found that excessive carbon in the steel that formed the reactor’s top and bottom could lead to unexpected cracks that could later spread.

The news comes as a shock to China’s burgeoning nuclear sector. With the completion date of the first project phrase expected by the end of this year, the Taishan EPR plant was a landmark project for China’s nuclear sector.

The plant’s two advanced 1.75GW pressurised water reactors were to be the world’s largest single-piece electric generators and their operation was said to be the safest, too.

Now it is not certain whether the Taishan reactors would comply with France’s stricter standards.

“Manufacturers must perform non-destructive tests on their products to guarantee their compliance,” the ASN said.

“However, some mechanical properties can only be measured by destructive tests, which cannot be performed on delivered equipment.

“Following a revision of the French regulations in 2005, ASN has required manufacturers to perform destructive and non-destructive tests on equipment (which are destroyed during testing) to qualify their manufacturing process.

“For the domes of the EPR main pressure vessel, those tests were performed in October 2014.

“Areva performed extensive non-destructive tests on all reactor vessel equipment, including on those shipped to China.

“But, as explained previously, the problem can only be detected by destructive tests.”

However, the ASN said Areva had a come up with a plan to deal with the problem.

“Over the next few months, Areva plans to perform comprehensive tests on equipment made with the same manufacturing process to fully characterise the problem, assess its impact on the safety of the reactors, (and) if need be, provide additional justifications and/or propose compensatory measures,” the ASN said.

China’s National Nuclear Safety Administration were informed about the problem were provided with information on Friday last week, the ASN said.

Areva said the Taishan reactors met Chinese nuclear standards.

“The reactor vessel heads for the Taishan reactors were evaluated as being in compliance with the Chinese regulations. The French and Chinese safety authorities are in contact following the information provided by the French watchdog,” the company told the Post.