Capturing Nuclear Power Plant Design Basis Configuration Through Effective Self Assessments

This paper emphasizes the importance of capturing all design basis changes especially in the civil/structural disciplines in a nuclear plant. Constant changes due to plant maintenance activities may lead to a potential loss of configuration, if these changes are not clearly understood and documented. By performing effective self-assessments, benefits gained are substantial and compliance is readily assured. It has been seen from experience that the current configuration control status of design documents such as calculations, procedure adherence, quality of posted changes, tracking aggregate impact, and understanding of the documentation update program by involved personnel is not clearly communicated. Various critical software structural and civil packages, piping specifications, and engineering evaluations, have outstanding changes posted against them as a result of continuing plant operational and maintenance work. Utilities that have nuclear plants also have a tendency to bank calculations, which has the potential to impact configuration control, since all changes that are banked are not supported with adequate backup calculations and justification. This may lead to loss of valuable time, should a plant emergency exist. Often a lack of aggregate impact of outstanding changes to plant design basis calculations continue to increase. Plants have been in operation for many years with reduced staffing levels. Additionally, due to limited resources, the aggregate impact of outstanding changes is not being formally tracked for all calculations. A lack of configuration control is often one of the precursors to safety significance or cost significant events. Increased management attention and allocation of resources is warranted to ensure that corrective actions are implemented. This will ensure that needed improvements are made to the configuration control of design documents. The paper outlines that by performing an in-depth review of changes posted against safety related documents, the potential to impact safety is substantially minimized. An effective self-assessment in the areas where numerous documents such as civil and stress calculations are generated may significantly ease the burden of maintaining adequate configuration.