The reactor pressure vessels in every European nuclear power plant should be subjected to a standardized review to check for manufacturing flaws (hydrogen-induced forging defects).The recommendation was issued by the Western European Nuclear Regulators Association (WENRA) to its members.
“After discovery of indications for manufacturing flaws affecting the reactor pressure vessel at the Belgian nuclear plants Doel 3 and Tihange 2 in Belgium, exhaustive investigations were carried out at the affected plants. We consider it important and necessary to be aware of this issue and that appropriate measures will be taken at every European plant”, said WENRA Chair Dr. Hans Wanner.
Hans Wanner thanked the Belgian nuclear safety authority (FANC) for the openness, transparency and co‐operation during the process of investigation.
Regulatory authorities in various countries have already decided to demand a safety review ‐ to check for manufacturing flaws ‐ from the operators of the plants under their supervision.
It is, however, recommended that measures are implemented on the basis of the same criteria, as WENRA Chair Wanner pointed out.
The recommendation now issued by WENRA includes guidance for the performance of the review. But it is up to the national nuclear safety authorities to define the necessity, testing scope, volume and non‐destructive method, depending on the available information on the vessels.
WENRA recommends two‐step procedure:
Step 1: Comprehensive review of the manufacturing and review records
Step 2: In case the national nuclear safety authority considers it necessary, representative
examination of the vessels with non‐destructive test‐methods.
The examinations should be carried out during the usual scheduled inspections. An unscheduled plant shut‐down is not necessary.
"The recommendation to review the reactor pressure vessels of all European nuclear power plants on account of the insights gained from the Belgian plants is an example of WENRA's active engagement on relevant technical issues concerning nuclear safety", said WENRA Chair Hans Wanner.
WENRA is a network of Chief Regulators of EU countries with nuclear power plants and Switzerland as well as of other interested European countries which have been granted observer status. WENRA elaborates safety reference levels for its members and has, in the past, published its position on various nuclear safety issues. For example, WENRA published this year a report on the safety objectives for new nuclear power plant designs based on a statement of 2010 on safety objectives for new nuclear power plants. In 2011, WENRA defined for ENSREG the specifications for the European post‐Fukushima stress tests. A position paper on periodic safety review, resulting from WENRA work on lessons learned from Fukushima was published in spring 2013.
"We intend to mobilize WENRA's expertise more and more on such important topics. As an association of competent and independent regulators, we can provide politically and economically independent viewpoints to support our members and inform the general public and politicians" emphasized Hans Wanner.