Review of R&D activities in Level-1 Probabilistic Safety Assessment and aging studies

This paper deals with the research and development activities in Level-1 Probabilistic Safety Assessment (PSA) and aging studies . Earlier, PSA models have been successfully employed during design evaluation in order to assess weak links and carry out design modifications to improve system reliability and safety. Now,studies are directed towards applying PSA in various decision making issues concerned with plant operations and safety regulations. This necessitated the development of software tools like Risk Monitor, Diagnostic System etc. in order to enable faster risk evaluation whenever the plant undergoes any design modifications as well as changes in component status and parameters or plant/system configuration. Also, research has been focussed into improving the PSA models and component failure data to be used. Paper highlights the research activities in reliability prediction of hardware and software components, so that realistic estimate can be used. Ageing studies play a vital role in equipment qualification as well as in life extension of components employed in plants. The paper highlights the experimental facilities available and their contribution in effective ageing assessment of Control and Instrumentation components used in Nuclear Power Plants (NPP).