One of the key recommendations from ENSREG following the completion of the European Stress Tests was to develop reference levels and guidance on the subject of natural hazards to drive harmonisation and improve safety. This recommendation resulted in new WENRA Safety Reference Levels (RLs) specific to natural hazards (Issue T), and a corresponding Guidance Head Document that contributes to a consistent interpretation of the RLs and provides insight into the considerations that led to their formulation.

The WENRA Reactor Harmonization Working Group (RHWG) recently completed the hazard specific annexes (Seismic Events, External Flooding, Extreme Weather Conditions) of the Guidance Document for Issue T.

The purpose of the hazard specific guidance documents is to provide additional explanations of the intent of the RLs of Issue T, specific to seismotectonic, external flooding and extreme weather conditions hazards.

The documents form annexes to the Guidance Head Document and should be read in conjunction with this Head Document. The guidance documents do not define any additional requirements. Furthermore, it is important to recognize differences in national regulations and in reactor designs when using this document. However, the overall content and meaning is in all cases relevant.