Periodic tests are technical inspections aimed at verifying the availability of the safety-related systems during operation. The French licensee, Electricité de France (EDF), manages periodic tests according to procedures, methods of examination and a frequency, which were defined when the systems were designed. These requirements are defined by national authorities of EDF in a reference document composed of rules of testing and tables containing the reference values to be respected. This reference document is analyzed and transformed by each “Centre Nucléaire de Production d’Electricité” (CNPE) into station-specific operating ranges of periodic tests.
In 2003, the IRSN noted that significant events for safety (ESS) involving periodic tests represented more than 20% of ESS between 2000 and 2002. Thus, 340 ESS were related to non-compliance with the conditions of the test and errors in the implementation of the procedures. A first analysis showed that almost 26% of all ESSs from 2000 to 2002 were related to periodic tests. For many of them, the national reference document and the operating ranges of tests were involved. In this context, the “Direction Générale de la Sûreté Nucléaire” (DGSNR), requested the “Institut de Radioprotection et de Sûreté Nucléaire” (IRSN) to examine the process of definition and implementation of the periodic tests.
The IRSN analyzed about thirty French Licensee event reports occurring during the considered period (2000-2002). The IRSN also interviewed the main persons responsible for the processes and observed the performance of 3 periodic tests. The results of this analysis were presented to a group of experts (“Groupe Permanent”) charged with delivering advice to the DGSNR about the origin of the problems identified and the improvements to be implemented.
The main conclusions of the IRSN addressed the quality of the prescriptive documents. In this context, EDF decided to carry out a thorough analysis of the whole process. The first conclusions of this analysis are presented in this paper.