ASN Report 2017

343 ASN report on the state of nuclear safety and radiation protection in France in 2017 Chapter 12  - EDF Nuclear Power Plants of the radioactive substances containment barriers and the operability of the control procedures in the event of an incident or accident. They also stipulate what is to be done if a required system fails or if a limit is exceeded, situations which constitute degraded operation. The STE evolve to take account of the lessons learned from their application and the modifications made to the reactors. Furthermore, on an occasional basis, the licensee can also modify them temporarily, for example to carry out an intervention in conditions that are different from those initially considered in the nuclear safety case. It must then demonstrate the pertinence of this temporary modification and define adequate compensatory measures. Depending on their nature, STE modifications likely to affect protected interests require either an authorisation application sent to ASN, or notification to ASN before they are implemented. More particularly, the modifications which significantly compromise the safety case are systematically the subject of an authorisation application. Until 31st December 2017, temporary STE modifications considered to be minor were eligible for the internal inspection arrangement implemented by EDF and thus complied with the requirements of Article 27 of Decree 2007-1557 of 2nd November 2007, as amended, concerning BNIs and the monitoring of the nuclear safety of the transport of radioactive substances. The internal authorisation systems were repealed on 1st January 2018. In 2017, the working of this internal inspection system was verified by spot-checks and inspections by ASN in the NPPs and in the EDF head office departments. Every year, ASN carries out an in-depth examination of the temporary modifications made to the STE, on the basis of an assessment prepared by EDF. This examination notably enables recurrent temporary modifications to be identified, which would require a lasting change to the STE. During inspections in NPPs, ASN verifies that the licensee complies with the STE and, as necessary, checks the compensatory measures associated with any temporary modifications. It also checks the consistency between the modifications made to the facilities and the normal operating documents, such as instructions, alarm sheets, the STE and the training of the persons responsible for implementing them. Periodic tests Elements Important for the Protection (EIP) of persons and the environment are equipment items identified by the licensee. They undergo qualification to guarantee their ability to perform their assigned functions in the situations in which they are needed. The periodic tests help verify that this qualification is maintained and regularly ensure that these elements are available when required. The associated rules constitute Chapter IX of the general operating rules for EDF reactors. These rules set the nature of the technical checks to be performed, their frequency and the criteria for determining the satisfactory nature of these checks, in other words the compliance of the equipment concerned with the qualification requirements. ASN ensures that the periodic technical checks on the EIP are relevant and are continuously improved. It carries out this verification when examining the application for authorisation to start-up the reactor and then the applications for authorisation to modify the RGE. In addition, during inspections, it verifies that these periodic technical checks are carried out in accordance with the test programmes stipulated in the RGE. Core physics tests The core physics tests contribute to the first two levels of defence in depth. Their purpose is, on the one hand to confirm that the core in operation is compliant with the design baseline requirements and the safety case and, on the other, to calibrate the automatic control and protection systems. These tests, prescribed in the RGE chapter concerning EDF reactor core physics tests, are performed periodically. The physics tests at restart are comparable to requalification tests following reloading of the core. The physics tests in progress and for the cycle extension guarantee the availability and representativeness of the instrumentation as well as the performance of the core in operation. The modifications to Chapter X of the RGE concerning core physics tests are made using a process similar to that for STE modifications and generally require ASN authorisation. During the on-site inspections, ASN checks the conformity of the tests performed (compliance with procedures and criteria to be verified) and EDF’s organisation during these particular operating phases. Operating rules in the event of an incident or accident Incident or accident operations In an incident or accident situation, the reactor operating strategies and rules are defined in the general operating rules. These evolve more particularly to take account of experience feedback from incidents and accidents, to correct the anomalies detected during their application or to take account of modifications made to the facilities, in particular those resulting from the periodic safety reviews. Implementation of the changes made is submitted to ASN for approval. ASN regularly checks the processes to draft and validate the incident or accident operating rules, their pertinence and how they are implemented. To do this, ASN can place the facility’s control teams in a simulated situation to check how they apply the above- mentioned rules and manage the specific equipment used in accident operating situations. It in particular ensures correct application of the emergency teams’ organisation principles described in the EDF baseline requirements validated by ASN in November 2014. This organisation more particularly requires that each emergency team member take part in an exercise every year.