ASN position statement of 20th April 2016 concerning generic guidelines for the periodic safety review associated with the fourth ten-year inspections for the 900 MWe reactors

In a letter to EDF dated 20^th April 2016, ASN stated its position regarding the EDF guidelines concerning the 4^th periodic safety review of the 900 MWe nuclear reactors.

This fourth periodic safety review is a particular event in three respects:

• First, forty years of operation corresponds to the initial hypothesis used in the design of certain reactor components and equipment. Extending their operation beyond this period means that these design studies must be updated to take into account operating experience feedback.
• Next, this fourth periodic safety review is an opportunity to complete the integration of the changes arising from the ASN prescriptions issued following the stress tests performed in the wake of the accident that struck the Fukushima-Daiichi nuclear power plant in Japan.
• Finally, in 2009, EDF stated that it wished to significantly extend the operating life of the reactors beyond 40 years, which implies a reassessment of their safety in light of the requirements applicable to new facilities, the state of the art with regard to nuclear technologies, and the operating life envisaged by EDF.

Given the particular context of this fourth periodic safety review for the 900 MWe plant series, which aims to ensure continued operation beyond 40 years, ASN aimed to ensure greater participation by stakeholders during the generic preparation phase. The following position statement was thus opened for public comments and consultation on the Internet from 26^th January to 16^th February 2016. All the comments received during this time will be collated, and a summary will be available for downloading.

After examination of EDF’s proposed guidelines, ASN considers that the topics selected by EDF in its programme correspond to the safety issues. However, ASN is asking EDF to supplement several aspects of its programme, more specifically with regard to the scope of the inspection programmes and the design improvement objectives.

Following the generic studies phase, ASN will also issue a position statement on the adequacy of the modifications planned by EDF.

The first ten-year inspection associated with this fourth periodic safety review for the 900 MWe reactors is scheduled for 2019 (Tricastin 1 reactor).

ASN’s position regarding the guidelines for the periodic safety review – VD4 900 MWe

In France, the operating life of a nuclear power plant is not defined in advance. In accordance with Article L. 593-18 of the Environment Code, the licensee of a basic nuclear installation must conduct a periodic safety review of its facility every ten years, after which ASN issues a position statement on the continued operation of the facility.

The periodic safety review comprises two parts: theconformity checkand thesafety reassessment. The conformity check constitutes a detailed examination of the facility in order to ensure that it does indeed comply with all the rules applicable to it.  In addition, the goal of the safety reassessment is to improve the level of safety with regard to the requirements applicable to facilities by considering more recent safety goals and practices.  This reassessment also takes into account changing knowledge and national and international operating experience feedback. The periodic safety review also makes it possible to check that the various ageing phenomena affecting the facilities will be satisfactorily controlled for a further period of at least ten years.

The 58 nuclear reactors operated by EDF are divided into large families called “plant series”: 900 MWe, 1300 MWe, 1450 MWe. Given the similarity among the characteristics of the reactors in the same series, the safety review process begins for EDF with a generic preparatory phase common to all the reactors of a given series. At the end of this phase, EDF sends ASN a “generic” review guidelines file (DOR) for the plant series concerned. This DOR describes the programme of work and the study documents to be submitted to ASN for assessment.

For the fourth ten-year safety review of the 900 MWe plant series, which will begin with the Tricastin reactor 1 in 2019, EDF transmitted its periodic safety review guidelines file at the end of 2012.  EDF then amended and updated these guidelines in mid-2014, presenting the 900 MWe generic inspections and studies it intends to carry out.

This fourth periodic safety review for the 900 MWe reactors is a particular event in three respects:

• First of all, forty years of operation correspond to the initial hypothesis used in the design of certain reactor components and equipment. Extending their operation beyond this period means that these design studies must be updated to take into account operating experience feedback.
• Next, this fourth periodic safety review is an opportunity to complete the integration of the changes arising from the ASN prescriptions issued following the stress tests performed in the wake of the accident that struck the Fukushima-Daiichi nuclear power plant in Japan.
• Finally, in 2009, EDF stated that it wished to significantly extend the operating life of the reactors beyond 40 years, which implies a reassessment of their safety in the light of the requirements applicable to new facilities, the state of the art with regard to nuclear technologies and the operating life envisaged by EDF.

Following an analysis of the various information supplied by EDF, and after asking IRSN and the Advisory Committees for nuclear reactors and for nuclear pressure equipment for their opinions in 2015, ASN issued a position statement in this present letter with regard to the general objectives identified by EDF and the topics requiring more in-depth examination.

After examination of the programme proposed by EDF, ASN considers that the topics selected by EDF are pertinent with respect to the safety issues. However, ASN is asking EDF to supplement several aspects of its programme, more specifically concerning the scope of the inspection programmes and the design improvement objectives.

Following the generic studies phase, ASN will also issue a position statement on the adequacy of the modifications planned by EDF.