This publication offers a framework for the qualification and survivability assessment of equipment in Nuclear Power Plants under Design Extension Conditions (DEC), including both scenarios without significant fuel degradation and those involving core melting. Aligned with Safety Standards Series No. SSG 69, the publication supports both new builds and existing plants undergoing backfitting, providing practical guidance on qualification approaches, determination of design inputs, and documentation practices. Drawing on international experience and current industry practices, it delivers valuable insights to help ensure that critical equipment can perform reliably under extreme conditions, thereby strengthening the resilience and safety of nuclear power plants worldwide.
