6 - Failure prevention and analysis in nuclear power plant systems, structures and components (SSC): a holistic approach

Abstract

Requirements for NPP SSC quality, defence-in-depth (DID) and accident management are discussed within the context of avoiding SSC failures and, should they occur, limiting their consequences. The concept of latent failure conditions (LFCs) in systems is introduced. Questions to ask and aspects to consider when investigating and analysing failures in NPP SSCs are presented. The circumstances already prevailing in the NPP at the time of the failure, and that may have contributed to it, are examined holistically to show how a comprehensive way of understanding the complete event can be arrived at. The development of a systematic approach to guide and assist in the identification of key causative factors and to facilitate an objective SSC failure analysis is explained.