Combining sensitivity analysis and scaling analysis for nuclear thermal-hydraulic studies

• A sensitivity analysis (GSA) in support of scaling. • How the sensibility and the scaling analysis can improve the distortions evaluation. • Guidelines for the future application of the GSA to the scaling analysis. • Application of system codes to scaling analysis. The scaling analysis of an accidental nuclear transient can identify the possible scale distortions between scaled down facilities and a real power plant. Advanced scaling approaches exist today in order to identify and quantify these distortions. There is also significant ongoing progress in evaluating the impact of distortions on a thermal–hydraulic transient using simulations of an Integral Effect Test (IET) and of a reference reactor transient using mature system codes. This paper presents some parallel application of a scaling analysis and of the General Sensitivity Analysis (GSA), a statistical tool used to identify the impact of a series of pre-selected input parameters e.g. physical models, to a specific Figure of Merit (FoM). This work identifies common and complementary potentials between the scaling analysis and the GSA. A counterpart test between BETHSY and LSTF facilities for a Pressurized Water Reactor (PWR) Small Break LOCA (SBLOCA) is analyzed in order to show the benefits of this strategy. The results suggest some guidelines to promote the combined use of GSA and scaling analysis.