Supervision of the EPR reactor
The EPR reactor is a pressurised water reactor (PWR) whose design, which has evolved with respect to that of the PWRs currently in operation in France, is intended to meet more stringent safety objectives.
Background and current situation:
Following the issue of the creation authorisation decree and the building permit, construction of the Flamanville 3 reactor began in September 2007. Initial pouring of concrete for the nuclear island buildings took place in December 2007. Since then, the structural civil engineering work has continued and is now completed. In 2014 and 2015, EDF completed the construction work of the inner containment and then the outer containment of the building designed to house the reactor. In 2014, the first large components (reactor vessel, steam generators, etc.) of the main primary system were introduced into the reactor building and welded to the main pipes of the system. Installation of equipment and components (piping, pumps, cables and electrical and instrumentation & control racks, etc.) has been completed. The main remaining activities concern finishing work on the installation. The start-up tests have progressed, with performance of the cold tests on the NSSS and the containment test in 2018 along with the hot tests performed in 2019 and early 2020. In 2020, ASN authorised the arrival of fuel on the site (partial commissioning). It is currently stored in a pool.
EDF must still carry out conformity work on the main steam letdown pipes and carry out the remaining start-up tests in order to prepare the reactor for loading with nuclear fuel (commissioning).
In June 2021, EDF renewed its commissioning authorisation application for the installation. This comprises the safety report, the general operating rules, the on-site emergency plan, the decommissioning plan, an update of the installation’s impact assessment and a risk control study. This application is being examined by ASN, with the support of IRSN.
ASN oversight concerns different fields:
- oversight of the construction work and the manufacture and qualification of the EPR equipment,
- assessment of nuclear pressure equipment conformity, particularly with regard to design and to manufacturing, assembly, installation and commissioning operations,
- oversight of the on-site start-up tests,
- technical examination of the design of the reactor and its equipment, more specifically examination of the documents transmitted for the reactor commissioning application,
- assessment of the preparedness of the teams in charge of future operation of the reactor.
This oversight is exercised by examining the technical documentation and performing inspections on the site, in the EDF head office departments and on the equipment manufacturers' premises.
ASN is currently continuing these oversight actions so that it can draft a technical opinion concerning the reactor commissioning application.
About two-thirds of the inspections carried out on the Flamanville EPR reactor construction site concern technical subjects in line with the progress of the work and the ongoing activities (mechanical assembly, start-up tests). The other inspections concern cross-cutting subjects (preparation for operation, organisation of occupational radiation protection, environmental protection etc.). These inspections are either carried out with advance notice to the licensee or are unannounced.
ASN also exercises its oversight with regard to labour inspection. ASN conducts inspections, some of which are unannounced, concerning occupational health and safety and the application of labour legislation. ASN works in close cooperation with the other relevant State services: DREETS, URSSAF, etc.
ASN also ensures oversight of the EDF engineering services responsible for carrying out and monitoring the detailed design studies and for monitoring the qualification and manufacturing activities, with performance of regular inspections in these services.
With regard to the manufacture of nuclear pressure equipment, ASN and the accredited organisations review the technical documentation concerning the design and manufacture of this equipment, and monitor its manufacture, particularly in the plants of the manufacturer Framatome, as well as its suppliers and their subcontractors.
ASN’s supervision of the Flamanville-3 reactor construction (EPR) : News
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ASN’s supervision principles for the construction of the Flamanville-3 reactor
On 10th April 2007, after consulting ASN, the Government issued the creation authorisation decree for the Flamanville reactor No.3, an EPR (European Pressurized water Reactor) reactor.
ASN's oversight of reactor construction falls within the general framework of the regulations applicable to basic nuclear installations supplemented by several ASN resolutions specifically concerning the EPR construction site (see Regulations tab).
In this context ASN:
- oversees reactor construction to ensure that it ultimately results in a reactor that meets the design requirements;
- examines the documents relative to the commissioning authorisation application provided for in article 20 of Decree 2007-1557 relative to basic nuclear installations.
ASN's oversight of the Flamanville reactor 3 construction involves the following activities:
- oversight of the construction work, the manufacture and qualification of the EPR equipment,
- assessment of nuclear pressure equipment conformity, particularly with regard to design, the manufacturing, assembly, installation and commissioning operations;
- oversight of the on-site start-up tests,
- technical examination of the design of the reactor and its equipment, and more specifically examination of the reactor commissioning application documents,
- assessment of the preparedness of the entity responsible for future operation of the reactor (the FLA3 NPP).
The principle regarding nuclear safety is thatprime responsibility lies with the licensee (EDF).
The objective of ASN oversight is therefore to ensure that EDF exercises its prime responsibility in full and controls:
- the conformity of the detailed design studies with respect to safety requirements;
- the conformity of the equipment production or installation activities, with the ultimate aim of assessing the overall quality of work performance;
- the impact of the worksite on the safety of the neighbouring BNIs and on the environment.
ASN directly oversees the design and manufacture, particularly by Areva, of the main nuclear pressure equipment (for example: the reactor vessel, the steam generators, and the pressuriser).
ASN is also responsible for labour inspection on the construction site.
ASN exercises its oversight through:
- examination of the detailed design documents;
- an inspection programme that addresses the activities of EDF's engineering services, the worksite and the manufacturers;
- examination of the handling of nonconformities or anomalies that can arise on a construction site of this scale. Under the Order of 7th February 2012, anomalies or deviations that arise during construction must be recorded and be dealt with by the licensee.
ASN receives technical assistance from the IRSN teams in its oversight activities.
With regard to labour inspection, the ASN inspector determines its oversight actions according to information brought to his/her knowledge, worksite progress and the ongoing operations. Oversight hinges around the examination of files, conducting inspections and the various requests made to the labour inspector.
To ensure successful oversight of the construction work, ASN relies primarily on:
- its Caen regional division, where a specific team carries out the worksite inspections and examines the handling of anomalies and non-conformities;
- its Nuclear Pressure Equipment Department (DEP) where a team is responsible for oversight of the manufacture of nuclear pressure equipment;
- its Nuclear Power Plant Department (DCN), which is responsible for examining the detailed design, inspections in the EDF engineering services and good coordination between the various ASN entities.
These activities mobilise the equivalent of 15 full-time ASN employees, as well as the personnel mobilised by IRSN.
 Order of 7th February 2012 setting the general rules concerning basic nuclear installations.
References concerning the Flamanville-3 EPR reactor