May 02, 2017

The manufacturing of nuclear reactor components

AREVA NP designs and manufactures the key nuclear steam supply system components for utilities all over the world. AREVA NP is active in the new build market as well as in the provision of replacement components for nuclear fleets in operation, supplying both heavy components (reactor pressure vessels, steam generators, pressurizers, etc.) and other mechanical equipment (reactor coolant pumps and control rod drive mechanisms).

These manufacturing processes are carried out under the supervision of dedicated internal teams, which are independent of operations, as well as of independent bodies and of customers, manufacturers or nuclear operators.

The regulatory framework is drawn up by the nuclear safety authorities. In France, the ESPN order relating to nuclear pressure equipment (Arrêté relatif aux Équipements Sous Pression Nucléaire – ESPN) sets out the regulations applicable to nuclear pressure equipment, and in particular those applicable to the primary coolant system of nuclear reactors. This order was published in 2006 and supplements the requirements of the previous regulation from 1974 and its corresponding applicable industrial code, the RCC-M Code. Compliance with regulatory requirements is in particular ensured by design qualification and monitored during manufacturing by means of inspections on a spot check or scheduled basis.

AREVA NP has three equipment manufacturing sites in France at Jeumont (Nord), Saint-Marcel and Le Creusot (Saône-et-Loire).

2 independent but concomitant events have led to the quality of past manufacturing at Le Creusot being called into question

October 2014

Within the framework of the assessment of compliance with ESPN order of the upper and lower domes of the reactor pressure vessel (RPV) of the EPR under construction at Flamanville (Manche), AREVA NP identifies mechanical characteristics that are not compliant with regulatory values. Analyses conducted show that the steel has a higher carbon content than that envisaged in certain zones of the RPV domes.

February 2015

Dysfunctions in tests performed on a machine at the Le Creusot mechanical testing laboratory are detected in end-of-manufacturing reports. The machine used for these tests is found to have had an anomaly since 2009 which was not picked up by the quality assurance system. AREVA NP decides to entrust the carrying out of quality audits to a team of internal experts and an external consultant. These audits bring to light irregularities, documentary anomalies and practices which are unacceptable from the point of view of quality in the manufacturing records of the Le Creusot plant.

As of 2015, EDF and AREVA NP work together to define an overall plan seeking to address all the issues related to the control and monitoring of manufacturing of nuclear pressure equipment, under the supervision of the ASN.

The key events to date

    • Publication of the ESPN order relating to nuclear pressure equipment (Arrêté relatif aux Équipements Sous Pression Nucléaire – ESPN)
    • June: casting of the ingot for the upper dome of the FA3 RPV
    • Acquisition of Sfarsteel (Creusot Forge and Creusot Mécanique) by AREVA
    • January: casting of the ingot for the lower dome of the FA3 RPV
    • Commissioning of a new machine for tensile tests at the Le Creusot laboratory
    • Issuing of the qualification report for the FA3 RPV domes
    • Commissioning of a second new machine for tensile tests at the Le Creusot laboratory
    • Committee of experts on application of the ESPN order confirming the application of criteria relating to mechanical properties in all zones of the equipment
    • Proposal to conduct additional tests on a part similar to the FA3 RPV domes
    • January: installation of the RPV on the EPR worksite at Flamanville
    • October: mechanical characteristics of parts of the FA3 RPV shown to be non-compliant with requirements of the ESPN order
    • February: dysfunctions brought to light in tensile tests performed at the Le Creusot Laboratory
    • May to October: series of quality audits conducted by internal and external teams on the Le Creusot site
    • June: drawing up of the justification program for the FA3 RPV domes including a program of tests and assessment by the French Nuclear Safety Authority (Autorité de Sûreté Nucléaire – ASN)
    • September: identification of components that could display high levels of carbon
    • September: analysis by a group of ESPN experts of AREVA’s methodology proposal to demonstrate theFA3  domes’ toughness
    • October: launching of further audits and a review of the Le Creusot plant's manufacturing records
    • December: acceptance by the ASN of the test program concerning FA3 RPV domes
    • February: "marked" records brought to light at Le Creusot site
    • April: completion of inventory of "marked records" and launching of analysis
    • June: quality review extended to the Jeumont and Saint Marcel sites
    • June: acceptance by the ASN of supplements to the justification program for the FA3 RPV following the group of ESPN experts meeting
    • August: start of review of 6,000 records for nuclear components archived at Le Creusot
    • August: high level of carbon segregation discovered in SG channel heads supplied by a Japanese sub-contractor
    • September: completion of processing of 244 "marked records" identified at Le Creusot
    • December: presentation of the Le Creusot improvement plan to EDF
    • December: submission of the justification file for the FA3 RPV domes, including results of the test program, to the ASN for examination
    • March: The ASN issues a communication on permission to restart reactors affected by high carbon segregation
    • March: start of forging on the Le Creusot site of test parts with a view to confirming the robustness of the quality plan

An expression of the value we place on integrity

AREVA NP is keeping its customers and the safety authorities concerned informed as to how work is progressing, whether it is on the program of additional tests on the domes of the Flamanville 3 RPV, the documentary review relating to past manufacturing operations or the action plans being implemented on its manufacturing sites to assure the quality of current and future manufacturing operations.

AREVA NP is also keeping all its stakeholders, both internal and external to the company, informed on a regular basis at meetings held to provide information and keep them up to date with the progress being made on these issues or by organizing visits to its sites.