EDF nuclear power plant at Fessenheim: review of compliance with the ASN requirements concerning reactor n°1

Published on 20/12/2012 • 11:56 am

Press release

ASN regularly verifies compliance with all 40 requirements set for continued operation of Fessenheim reactor n°1[1]. On 18 July and 11 December 2012, in particular, ASN carried out inspections on the site to ensure compliance with the requirements for which the deadline is imminent. ASN considers that the actions so far taken by the licensee to comply with its requirements are satisfactory[2] and [3].

An initial important requirement is the construction of the “emergency ultimate heat-sink” facility, an additional emergency cooling system requested by ASN. The deadline for this requirement is 31 December 2012. Satisfactory progress is being made on the work, but significant efforts are still needed so that, in addition to the hardware, all the necessary documentation for the use of this system is in place by the end of the year. In any case, the system should be fully operational by that date.

The second major requirement concerns the reinforcement of the reactor basemat, which should be completed before 30 June 2013. After examining the dossier submitted by EDF, ASN gave its approval on 18 December 2012 for EDF to implement the proposed modification subject to compliance with additional conditions designed to guarantee both the radiation protection of the staff performing the work and attainment of the specified safety objectives[4]. The modification is designed to increase both the thickness and surface area of the corium spreading zone used in a severe accident with reactor vessel melt-through. It leads to a “very significant increase” in the basemat’s ability to withstand the corium (requirement FSH1-25)[5].
 When examining this dossier, ASN drew on an analysis by IRSN, its technical support organisation, and a complementary expert assessment regarding the strength of the concrete[6].

Finally, for three of the 40 safety requirements set by ASN, EDF proposed solutions involving the use of means that differed from those initially imagined. After examining these proposals, ASN modified the formulation of the three requirements in question. The implementation deadlines and the safety objectives set by ASN remain unchanged[7].

ASN will continue to ensure compliance with and satisfactory implementation of these requirements by means of inspections, especially during reinforcement of the basemat.

In the first half of 2013, ASN will also issue a position statement regarding the continued operation of the plant’s number 2 reactor, for which the third ten-yearly outage inspection ended in March 2012[8].

ASN regularly informs the public about its regulation and monitoring of the Fessenheim plant on its website and through information briefings at meetings of the Fessenheim local information and monitoring committee (CLIS).

Basemat diagram

To find out more:

  1. ASN resolution n°2011-DC-0231 of 4 July 2011 (in french)

  2. Follow-up letter to the "Compliance with requirements for continued operation of reactor n°1 and climatic hazards" inspection
    Inspection of : 11/12/2012
    INSSN-STR-2012-0863 (PDF - 213,35 Ko) (in french)

  3. Implementation by the site of the requirements linked to continued operation of reactor n°1
    Inspection of : 18/07/2012
    INSSN-STR-2012-0804 (PDF - 193,54 Ko) (in french)

  4. Approval subject to implementation of the hardware modification (in french)

  5. Press release of 4 July 2011: "ASN states its position on continued operation of reactor No. 1 of the Fessenheim nuclear power plant" (in french)

  6. IRSN opinion on the modification of the Fessenheim reactor n°1 basemat, dated 28 November 2012 (in french)
    "Validation of concrete parameters" report of 12 December 2012 (in english)

  7. ASN resolution n°2011-DC-0328 of 11 December 2012 (in french)

  8. Outage for ten-yearly inspection of Fessenheim NPP reactor n°2 (in french)
    From 25 August to 12 September 2012

Press contact: Evangelia Petit, head of media department, tel. : 01 40 19 86 61, evangelia.petit@asn.fr

Date of last update : 30/05/2017