Update on Quality Assurance Issues in France

David McIntyre
Public Affairs Officer

Today, the NRC is releasing information about large reactor components supplied to U.S. nuclear plants by AREVA’s Creusot Forge in France. This information includes the names of the plants and the reactor components involved.

This blog post discusses the information as well as the NRC’s actions related to ongoing French investigations into potential defects and problems with quality assurance documents regarding the parts’ manufacture.

We are confident at this time that there are no safety concerns for U.S. nuclear power plants raised by the investigations in France. Our confidence is based on the U.S. material qualification process, preliminary structural evaluations of reactor components under scrutiny in France, U.S. material aging-management programs, our participation in a multinational inspection of Creusot Forge, and information supplied by AREVA about the documentation anomalies. Also, the components supplied to U.S. plants have performed well and inspections during their operating life have revealed no safety issues.

Because there are no immediate safety concerns, there is no justification for the NRC to order plants to shut down and inspect components, as some groups have suggested. Should new information raise a specific safety concern, the agency will take appropriate action.

The information released today ML17009a275 was provided to the NRC on Dec. 15 at our request by AREVA, a multinational manufacturer of nuclear plant components.  We informed AREVA on Dec. 30 of our intent to make the information public (ML16364A034). Attachment A lists components with forgings from Creusot Forge supplied to 17 U.S. reactors at 13 sites, directly by AREVA or through third-party vendors. The components are mostly replacement reactor vessel heads, replacement steam generator components or pressurizers. AREVA clarified the list in letters dated Jan. 9 and Jan. 10, which are included in the information.

We posted a piece last June about the investigation by the French Nuclear Safety Agency, ASN, into AREVA’s Creusot Forge. Here is an update:

There are two separate, but related, issues to the investigation in France. The first is called “carbon segregation,” a condition that in certain circumstances could create local areas of reduced toughness in large forged components of nuclear plants. The second is a series of anomalies discovered in the quality assurance documentation of components manufactured at Creusot Forge.

Carbon segregation occurs naturally during the casting of steel ingots. Carbon molecules concentrate as newly forged ingots cool. Most of this excess carbon is cut away and discarded before the actual plant components are formed, but some processes leave small areas of elevated carbon content near the component’s surface. NRC regulations and code requirements by the American Society of Mechanical Engineers account for this condition. Higher-than-expected carbon segregation has been discovered on some reactor components in France that were manufactured using a particular process, though there are no indications it would exceed U.S. limits. We’ve asked AREVA if any components supplied to U.S. reactors were manufactured using that same process, and we expect the company’s answer soon.

While investigating the carbon segregation issue, ASN discovered anomalies in the documents describing how components were manufactured at Creusot Forge. This probe, launched last May, has since expanded to include a review of documents dating back to 1965. (AREVA acquired Creusot Forge in 2006.)

Two NRC inspectors participated in an inspection of the Creusot Forge facility in late November/early December. The inspection team included inspectors from France, the United Kingdom, Finland, China and Canada, and was conducted under the Multinational Design Evaluation Programme, which facilitates information exchanges among nations. During the inspection, AREVA reported that some files on components supplied to U.S. nuclear plants contained anomalies. The company said the anomalies presented no apparent safety concerns.

The NRC inspectors conducted a preliminary review of records for three U.S. plants and agreed that AREVA had made a reasonable assessment of no safety concerns.

The ASN, which led the inspection, is expected to issue a report on its findings in the next several weeks. Meanwhile, AREVA filed an interim report to the NRC on Dec. 7 (ML16344A120), providing more information about document anomalies affecting some U.S. plants. AREVA said it had notified its U.S. customers (including nuclear power plants and vendors) of the documentation issues and its assessment that there are no related safety concerns. The company said it expects to complete its evaluation of Creusot Forge’s documentation processes for U.S. plants by June 30, 2017.

We are not taking this issue lightly. Complete and accurate documentation provides assurance that components were forged to the proper procedures and specifications. As the investigation continues, we remain alert to any indication that the documentation irregularities at Creusot Forge might call into question the safety of these components and U.S. nuclear plants.

 

Quality Assurance Issues in France: Implications for U.S. Plants?

Kerri Kavanagh
Chief, Quality Assurance and Vending Inspection Branch

The NRC doesn’t just oversee how nuclear power plants operate. We also oversee the quality of the important components that go into the reactors. That’s why NRC staffers are working with the French Nuclear Safety Authority and AREVA, a manufacturer of reactor components, to determine if a quality assurance investigation underway in France has implications for U.S. plants.

ASN – the acronym for the French regulator — requested the probe in early May after a flaw was discovered in the vessel of a reactor under construction at Flamanville in France. So AREVA checked the manufacturing records of the Le Creusot Forge, in central France. They found anomalies in the records of about 400 parts manufactured there since the plant opened in 1965. (Le Creusot Forge was purchased by AREVA in 2006.)

investigationsASN says these are paperwork irregularities – inconsistencies, modifications or omissions in production files concerning manufacturing parameters or test results. The irregularities are troubling because complete documentation provides assurance the components were forged to the proper procedures and specifications.

They do not mean, however, that any parts or components manufactured at Le Creusot are defective.

AREVA announced at the end of May that it had completed two-thirds of its review and found no indications of safety issues. The company told the NRC about 10,000 documents are still under review. The company pledged to provide us with a list of U.S. plants affected by these paperwork irregularities when the investigation is completed around the end of July. We’ll continue to engage with ASN and AREVA to make sure we have a complete picture of how these irregularities may affect any components provided to U.S. nuclear power plants.

NRC’s regulations in 10 CFR Part 21, “Reporting of Defects and Noncompliance,” require any entity that identifies reportable issues to evaluate them and inform the users of any impacted components. The users then have 60 days to do their own safety evaluations. If the users identify significant safety hazards, they must report these to the NRC by phone within two days, and in writing within 30 days.

AREVA and Le Creusot Forge are under contractual obligations to their U.S. customers (who are NRC licensees) to follow these reporting requirements. We’ll take appropriate regulatory and enforcement action if we find issues of safety significance. At this time, there is no indication of a safety issue with any components from Le Creusot covered by this quality assurance audit.

Regarding new reactors, Westinghouse Electrical Co., the architectural engineering firm for the AP1000 reactors under construction at Vogtle and V.C. Summer, has confirmed that no components at these plants were supplied by Le Creusot Forge.

Once AREVA completes its audit and we have a complete picture of the situation, the NRC has several options. We may issue a generic communication to keep the broader nuclear industry informed. We may also perform inspections to ensure conformance and compliance with our regulations.

More information will be coming on this issue. If the NRC determines that Le Creusot Forge has provided components to U.S. nuclear power plants, we’ll make sure those components are fully evaluated to determine any impact the documentation irregularities might have on their safety-related functions.