ASN states its position on the continued operation of reactor No. 1 of the Fessenheim nuclear power plant

Published on 22/07/2011 • 04:57 pm

Press release

In its opinion No. 2011-AV-0120 of 4 July 2011, ASN considers that subject to the forthcoming conclusions of the complementary safety assessments initiated following the Fukushima accident and in view of the result of the third periodic safety review of reactor No. 1 of the Fessenheim nuclear power plant, that reactor is capable of being operated for a period of ten more years after the third review, provided that the requirements in ASN resolution No. 2011-DC-0231 dated 4 July 2011 are complied with, particularly the following two main requirements:

  • Strengthen the reactor basemat by 30 June 2013 to increase resistance to corium in the case of a severe accident with reactor vessel breakthrough;
  • Install emergency technical systems by 31 December 2012 to remove residual heat reliably in the event of loss of ultimate heat sink.

In France, the licence to operate a nuclear power reactor does not specify any predetermined time limit. In this context, article 29 of the Act on “Transparency and Security in the Nuclear Field” of 13 June 2006 (TSN Act) requires an operator of a nuclear reactor to conduct a periodic safety review of the installation every ten years, after which ASN states its position on its continued operation.

Firstly, the periodic safety review offers the opportunity both to examine the installation condition in depth and to check that it actually complies with all the applicable regulatory requirements and provisions (conformity check). Secondly, its objective is also to improve its safety level in line with the requirements applicable to installations with more recent safety objectives and practices and taking into account the latest developments in national and international know-how and operating experience (safety reassessment). The purpose of periodic safety review is also to verify that the diverse ageing phenomena of the installations will be under control for a minimum period of ten more years.

Reactor No. 1 of the Fessenheim nuclear power plant is the second French nuclear reactor to undergo a ten-yearly safety review thirty years after its commissioning. The reactor had been shut down for its third ten-yearly inspection from 17 October 2009 to 24 March 2010, during which time ASN carried out twelve inspections and supervised hydrotesting for requalification of the primary system. EDF sent its final report to ASN on 10 September 2010 at the end of a procedure initiated in 2003.

ASN is imposing technical demands on EDF, based on the periodic safety review, which set new operating conditions for reactor No. 1 of the Fessenheim nuclear power plant. These demands mainly include requirements which are applicable to installations with more recent safety objectives and practices.

This ASN resolution does not prejudge future conclusions resulting from the complementary safety assessments undertaken following the Fukushima accident in accordance with the resolution of ASN Commission of 5 May 2011. These complementary assessments will cover all basic nuclear installations, including Fessenheim.

Furthermore, according to its permanent missions, ASN carries on maintaining continuous supervision of the operation of reactor No. 1 of the Fessenheim nuclear power plant.


  • ASN generic position: Extension of the operating lifetime of 900-MWe nuclear reactors up to 40 years: ASN considers as satisfactory the conclusions of the generic studies carried out by EDF (7 July 2009)

Press contact: Evangelia Petit, press relations manager, tel.: + 33 1 40 19 86 61,

Date of last update : 08/06/2017