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 virtually 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 system pipes. Installation of equipment and components (piping, pumps, electrical and instrumentation & control cabinets and cables, etc.) continued and is currently being completed to allow performance of the reactor start-up tests. These start-up tests are well advanced, with the performance of cold tests of the nuclear steam supply system and the containment hydrotest in 2018, along with a first phase of the hot tests performed in early 2019. After completion of the hot tests, EDF will be required to carry out conformity work on the main steam transfer pipe welds and carry out the remaining start-up tests in order to prepare for loading of nuclear fuel into the reactor (commissioning). At the same time, EDF is preparing for the arrival of this fuel on the site (partial commissioning).

copyright EDF Médiathèque - EPR nuclear power plant in Flamanville, France, mars 2019

ASN received the Flamanville 3 commissioning authorisation application file on 19 March 2015. This file was transmitted by EDF in accordance with article 20 of Decree 2007-1557. It contains a safety analysis report, general operating rules, a waste management study, a decommissioning plan, an on-site emergency plan and an update of the impact assessment. Installation commissioning corresponds to the introduction of the first fuel assembly into the reactor vessel. It is subject to the prior delivery by ASN of the installation commissioning authorisation. On the same day, EDF submitted the partial commissioning authorisation application file to ASN (step corresponding to the nuclear fuel being brought within the perimeter of the Flamanville 3 BNI).

ASN considers that the two files submitted by EDF are admissible. ASN nevertheless considers that additional information is required before their technical examination can begin. ASN thus informed EDF of its conclusions and listed the additions, corrections and justifications required for the various documents by letter dated 12 June 2015 for the commissioning authorisation application file and by letter dated 13 July 2015 for the partial commissioning authorisation application file.

In June  2017, ASN received updated versions of the commissioning authorisation and partial commissioning authorisation files. Some elements still need to be provided before ASN is able to issue a position statement on the commissioning authorisation application file. In 2018, ASN notably issued requests for additional data regarding the general operating rules.

ASN also obtained the opinion of the Advisory Committee for Reactors (GPR) on 4 and 5 July 2018 concerning the safety analysis report for the Flamanville EPR. This meeting was more particularly devoted to the follow-up to the previous GPR sessions devoted to this reactor since 2015.

On 26 July 2018, ASN authorised the introduction of steam containing tritium into certain Flamanville EPR reactor systems in order to prepare for and carry out the hot tests. This authorisation required the implementation of new resolutions regulating water intake and consumption, effluent discharges and monitoring of the environment around the Flamanville site. These resolutions were updated on 28 September 2018 and then came into force on 7 October 2018.

ASN oversight:

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 entity responsible for future operation of the reactor (the Flamanville 3 NPP).

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 carried out 20 inspections of EDF on the construction site in 2018 (of which 4 were unannounced). These inspections more specifically concerned the following technical subjects:

  • preparation for and performance of the containment hydrotest;
  • mechanical assembly work, notably an examination of the records of the main steam transfer pipe welds and of their initial inspection on completion of manufacturing, the organisation adopted to re-inspect them and the improvements made for the weld repair work;
  • the organisational set-up for performing the reactor start-up tests;
  • the non-destructive tests and worker radiation protection;
  • the preparedness of the team in charge of future reactor operations, more particularly in the fields of environmental protection, in-service monitoring of pressure equipment and nuclear pressure equipment (ESP/ESPN), fire risk control and reactor operations;
  • protection of the environment.

ASN also exercises its oversight with regard to labour inspection. ASN conducts unannounced inspections concerning occupational health and safety and the application of labour legislation. ASN works in close cooperation with the other relevant State services: DIRECCTE, URSSAF, etc.

ASN also ensures oversight of the 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 ESPN and monitor the manufacturing of this equipment, particularly in the plants of the manufacturer Framatome (ex-AREVA NP), as well as its suppliers and their subcontractors.

ASN’s supervision of the Flamanville-3 reactor construction (EPR) : News

Read the newsletters about the supervision of the Flamanville-3 reactor construction (EPR) ...

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.


References concerning the Flamanville-3 EPR reactor

Date of last update : 17/04/2019