Development of a systematic approach for quantification of thermal hydraulic code model input uncertainty
Résumé
Uncertainty analysis (UA) is a key element in nuclear power plant (NPP) deterministic safety analysis using
best-estimate thermal hydraulic codes and best estimate plus uncertainty (BEPU) methodologies. If forward
uncertainty propagation methods have now become mature for industrial applications, the input
uncertainties quantification (IUQ) on the physical models still requires further investigations. The
OECD/NEA PREMIUM project attempted to benchmark the available IUQ methods, but observed a strong
user-effect due to lack of best practices guidance. The SAPIUM project has been proposed towards the
construction of a clear and shared systematic approach for input uncertainty quantification as it is already
addressed in industries and R&D for related topics. The main outcome of the project is a first “good
practices” document that can be exploited for safety study in order to reach consensus among experts on
recommended practices as well as to identify remaining open issues for further developments. This paper
presents the systematic approach that consists in five elements in a step by step approach to perform a
meaningful model input uncertainty quantification & validation, the key issues to be addressed for each
step as well as some “good practice guidelines” recommendations and open issues on the tools and methods to be used for each step.