Summary of the IRSN report on the safety review carried out by EDF as part of the third ten-yearly inspection of 900 MW reactors

IRSN (the French Institute for Radiation Protection and Nuclear Safety) presents its assessment of the sufficiency of studies conducted by EDF as part of the safety review associated with the third ten-yearly inspection of 900 MWe reactors (VD3-900). The IRSN presents the modifications envisaged as a result of these studies, in relation to the objectives initially set for this safety review with a view to enabling the French nuclear safety authority (ASN) to give an opinion on the suitability of the 900 MWe reactors for continued operation until the fourth ten-yearly inspection (VD4). The topics and studies assessed in this context are as follows: 1 - Internal and external hazards:Internal flooding and rupture of high- and medium-energy pipes; Internal site explosions; Fire; Seismic testing approach; Climate-related aggressions; Unit and site autonomy against common-mode external hazards; 2 - Studies of accidents and their radiological consequences: Risk of cold overpressure; Passive failure of safety injection circuit; Steam generator tube rupture - No water overflow; Severe accidents / Update of level 2 probabilistic safety assessment; Update of level 1 probabilistic safety assessments; Containment in post-accident situations; Behavior of containment systems; Compliance of ventilation/filtration systems with containment requirements; Operability of equipment called out in beyond-design-basis and ultimate situations; 'State approach' instrumentation - Post-accident monitoring; information; 3 - Design of civil engineering systems and structures: Checking the design of civil engineering structures; Radioactivity measurement system operation; Reliability of the deactivation pool cooling system; Safety injection system functional capabilities; RIS-EAS recirculation function reliability; 4 - 'Out-of-review' reference systems: Criticality, Radiological consequences, New complementary field, Heat waves, Lowest safe water level, Pumping station; 5 - Programs for unit conformity assessment and further investigations: Unit conformity assessment, Complementary investigation program; 6 - Process associated with the preparation of suitability files for the continued operation of units