French firm AREVA says that additional studies have, so far, confirmed the quality of the forged components for the Flamanville 3 EPR, which is under construction in northern France. However study of the forgings and the quality processes at the Creusot Forge plant are still ongoing.
The news comes two weeks after AREVA informed the French nuclear regulator that chemical and mechanical tests conducted in late 2014 on a reactor pressure vessel head similar to that of the Flamanville EPR had revealed an area with high carbon concentration. At the time AREVA and plant owner EDF pledged to perform additional tests as soon as possible to demonstrate the safety and quality of the corresponding equipment.
AREVA said that so far the analyses have examined questions related to the fabrication of forgings for the Flamanville 3 reactor vessel and similar analyses previously conducted on other forging. In 2005 the French authories brought in a new order on nuclear pressure equipment (ESPN), and the Flamanville 3 vessel must comply with new mechanical specifications.
Analyses also concern a mechanical testing laboratory at the Creusot where a material inspection tool was "inaccurately used" for hot tensile testing measurements from 2009 to 2014. This problem, AREVA said, means that reinterpretation of results or repeats of certain tests are required.
"These assessments have confirmed thus far the intrinsic quality of the forgings and the safety of components," AREVA said. It also confirmed that none of the components subject to the faulty testing procedure are installed in an operating reactor.
Meanwhile EDF said, 20 April, that on the basis of the information available, work can continue on Flamanville's EPR site.
Independent quality review
AREVA has appointed French-British company Lloyd's Register Apave Limited to carry out an external review of areas related to forging and inspections.
This review, which will begin on 4 May, is expected to last for at least two months.
AREVA said it would help the company "to identify the causes of potential defects in practices and in quality inspections," as well as improvement measures.
The Creusot Forge, acquired by AREVA in 2006, specialises in the manufacturing and machining of major forgings and castings. It is one of the only forges in the world capable of producing components for the nuclear island.