プレスリリース - 2016-11-01
1 November 2016, Tokyo - Documents on the carbon steel crisis submitted by Japan’s nuclear utilities to the Nuclear Regulation Authority (NRA) (1) are inadequate and unconvincing, Greenpeace Japan claimed today. The eleven power companies were under order of the NRA to investigate that steel components installed in their nuclear reactors were free of increased carbon concentrations. But the documentation submitted to the NRA are only records from the time of manufacture, which in France have been found not to be accurate.
Steel supplied by Japanese manufacturers to the French nuclear program have been found to have carbon contents outside regulatory limits, with major implications for nuclear safety, including reduced toughness of the steel and increased risk of catastrophic failure. Greenpeace Japan released a report from an independent nuclear engineer last week that detailed some of the implications for the Japanese reactor fleet if it was found that there was excess carbon found in reactor pressure vessels and steam generators.
“The nuclear industry in France is now in crisis as a result of the carbon test results, with 11 reactors supplied by Japanese steel ordered shutdown and under investigation by the regulator. The Japanese nuclear industry is desperate to shut the door on this issue and avoid a repeat of what is happening in France. However, it was only after the French regulator ordered non destructive and destructive testing(1) that the true scale of the excess carbon problem was confirmed. No such testing has been done in Japan. None of the documentation released by the utilities demonstrates what the carbon concentration is in the actual installed components. And until actual testing is conducted, the NRA, and more importantly the communities living near nuclear reactors, will not know what risks the nuclear plants pose. The NRA cannot allow this to be a paper exercise on the part of the utilities. The NRA must instruct utilities to undertake non destructive and destructive testing as a matter of urgency, the priority being the Sendai-2 and Ikata-3 reactors which are the only operating plants,” said Shaun Burnie, nuclear specialist at Greenpeace Germany.
Steel under investigation in the French nuclear reactor program was supplied by Japan Casting and Forging Company and Japan Steel Works. Both supplied the steel for Japanese reactors, together with JFE. The AREVA owned le Creusot steel forge is also under investigation.
Notes:
(1) The submissions to the NRA are available at: https://www.nsr.go.jp/
(2) Non destructive testing refers to the external inspection of steel components by portable spark optical emission spectrometry (OES) and ultra sound scanning. They have their limitations and cannot show carbon content inside or through the steel. Destructive testing can be both on newly manufactured components but also on existing installed components. AREVA found through destructive testing that carbon concentrations, or positive macrosegregation increased from the surface through the depth of the steel.
Contacts:
Shaun Burnie, senior nuclear specialist, Greenpeace Germany (Tokyo):
, +81 (0)80 3694 2843
Chisato Jono, communications officer, Greenpeace Japan: 
, +81 (0)80-6558-4446