September 14, 2017

Le Creusot manufacturing records: a methodical and systematic analysis of all deviations

Subsequent to the discovery of deviations in the compilation of manufacturing records at Creusot Forge, in September 2016, AREVA NP embarked on an exhaustive process of review covering all records for parts manufactured on the site for nuclear installations since the 1970s.

Teams specially put together at AREVA NP are responsible for carrying out the inspection work and then processing the deviations in coordination with the customers and the Safety authorities concerned.

Step 1: the records are inspected page by page to identify findings

This manufacturing record for each part consists of different documents which provide a trace of the steps in the manufacturing process (mechanical and chemical test reports (procès verbaux – PVs), history of forge operations, heat treatment graphs, tracking sheet, routing sheet, etc.). These elements are used to compile the end-of-manufacturing report (EMR) [rapport de fin de fabrication – RFF] which is submitted to the customer. Each record in general consists of several hundred pages. These EMRs or records are inspected page by page, line by line. For each point in the guide, the result of the inspection is entered in a database as a finding. Compliance with the requirements applicable at the time of manufacturing is verified for each parameter and recorded in the review guide. Similarly, if some documents are not present or if inconsistencies are identified, they are recorded in the guide. For certain chemical analyses, the test reports present in the records are compared with the original test report which it has been possible to retrieve from the laboratory responsible for performing the tests.

Due to this methodology which ensures the exhaustive and transparent review of records, numerous findings are made. The majority of them are related to the fact that certain information is not included in the records, in particular given the archiving rules for certain internal documents, some of which date from over thirty years ago.

Step 2: the findings are analyzed to determine the mode of processing

An analysis of findings allows them to be classified into three categories: no deviation; internal non-conformance notice; non-conformance report.

The majority of findings are findings with no deviation: these findings where there is no deviation are cases where the examination shows the absence of any deviation with respect to internal instructions, specifications stated in the order or requirements stated in the code or regulations. In the case of these findings with no deviation, all the substantiating elements required for the technical analysis are available in the file and no additional elements are necessary.

For deviations from an internal specification or plant quality assurance system, an internal non-conformance notice [NCN] (fiche de non-conformité – FNC) is opened and a justification of the acceptability of the part is prepared by a technical team based on the elements available in the record. The NCN is sent to the customer for information purposes.

If it is a case of a deviation from a code, regulations of customer specifications, a non-conformance report [NCR] (fiche d’anomalie – FA) is opened. In the majority of cases, the technical analysis leads to them being proposed for acceptance as they are on the basis of the elements present in the record and possibly based on additional analyses. In some cases, additional tests are necessary to confirm the serviceability of the part. To be able to close the NCR, it is necessary to have the customer's approval.

Step 3: each anomaly is processed by experts

The non-conformances identified are now broken down into 6 main families:

  • Mechanical characteristics of the part that do not meet the criterion
  • Chemical composition of the part that does not conform with the specification
  • Discard ratio of the forged part that does not meet the criterion
  • Untraced deovalization operations performed on the forged part
  • Dimensional characteristics of the part that do not conform with the specification
  • Deviation in heat treatment conditions.

AREVA NP draws upon its skills in mechanics, inspection and materials science to process these non-conformances. The customer's approval is necessary in order to implement the solution for processing the non-conformance, whether this is in the form a justification relative to regulations or the performance of additional tests to demonstrate the safety of the part.

Once the solution has been implemented, the non-conformance reports and the internal non-conformance notices can be closed out with the customer's approval. Depending on the regulations applicable in the country concerned, the non-conformance reports are sent by the customer to the Safety authority for approval.

Report on progress to date

In France, this analysis gives rise, for each reactor, to the drafting of a summary report which is submitted by EDF to the French Nuclear Safety Authority (ASN) for examination no later than two months prior to the scheduled restart date for the reactors concerned. To date, AREVA NP, under the supervision of EDF, has drafted the reports for the first 12 units of the fleet in accordance with the milestones defined by EDF and the ASN. An analysis of the deviations identified in these reports has concluded that none of them are of such a nature as to call into question the serviceability of the equipment concerned for totally safe operation.

A painstaking review mobilizing the efforts of teams from AREVA NP

This purpose of this painstaking activity of review and justification of all deviations is to demonstrate the quality of the parts manufactured on the Le Creusot site. This activity is set to continue into 2018.

David Emond, Director of AREVA NP's Components BU, comments "AREVA NP's teams are working with professionalism and transparency to deal with the deviations identified and implement improvements for future production. Regular visits and inspections are organized so that our customers and the Safety authorities can check that the review is proceeding properly. The complete review of past production is necessary in order to demonstrate the quality of the components manufactured at Le Creusot, to rebuild the confidence of our stakeholders, to learn the lessons from the irregularities brought to light and to safeguard the future of the site."