Qualitative Approach for Selection of Systems Structures & Components

This report presents a qualitative approach for selection of Systems, Structures & Components (SSC) sensitive to ageing. The purpose of selection is to model and evaluate SSC ageing effects on the overall NPP safety by applying Probabilistic Safety Assessment tool. The report was prepared by Institute for Nuclear Research, Pitesti, Romania in cooperation with Institute for Energy, EC Joint Research Center, Petten, Netherlands in the frame of EC JRC Ageing PSA Network Task 3 activities. The goal of the work is to demonstrate the feasibility of qualitative assessment in selection of components sensitive for ageing and to develop a viable guideline for selection of components susceptible to ageing. An overview of the available approaches for selection of ageing components was performed, and the methods are briefly presented. Their advantages and disadvantages, as their limitation are also specified. Applicability of the approach for qualitative selection of SSC susceptible to ageingwas demonstrated by a case study which use as an example SSC of NRI TRIGA research reactor. A list of ageing mechanisms, as their favourable factors for occurrence is provided in appendices of the report.