One of the key aspects of nuclear safety and continuous improvement is a strong periodic safety review (PSR) process. WENRA reference revels (RLs) for existing nuclear power plants cover the topic of PSR in Issue P. According to the RLs, the PSR shall be made periodically, at least every ten years. The licensee has the prime responsibility for performing the PSR. All reasonably practicable improvement measures shall be taken by the licensee as a result of the review. The European stress tests organised by the ENSREG emphasised also the importance of the PSR process. In the action plan for the follow-up of the peer review of the stress tests performed on European nuclear power plants, ENSREG encourages WENRA to undertake a review of the associated Reference Levels, particularly with respect to external hazards. WENRA publishes now a position paper on PSRs taking into account the lessons learnt from the TEPCO Fukushima Dai-ichi NPP accident.
The TEPCO Fukushima Dai-ichi accident demonstrates the importance of properly implementing the Defence-in-Depth principle, to ensure safety, getting the design basis for external hazards right, providing adequate protection against external hazards, and the need to ensure a strong PSR process together with independent regulatory body to drive it. Concerning the scope of PSR, it is recognised that natural hazards should be more systematically reviewed during a PSR. No major modifications are expected concerning the PSR process itself. However, it is expected that WENRA countries take measures to make the process as transparent as possible to the stakeholders and the public. This should improve societal confidence on the nature and scope of the PSR and the licensees commitment to address any PSR findings. The following areas are recognised for improvements in the WENRA RLs Issue P:
- the timely and effective implementation of improvements derived from the PSR
- review of site characteristics regarding external hazards
- more explicit guidance on the need for comprehensive analysis of all hazards and plant faults
- taking into account multiple-unit issues.
WENRA Position Paper on Periodic Safety Reviews