Assessment of SIMMER-III code in predicting water cooled lithium lead breeding blanket “in-box-Loss of Coolant Accident”

The in-box Loss of Coolant Accident is a major safety concern for the Water Cooled Lithium Lead Breeding Blanket design. SIMMER-III code has been modified by University of Pisa and ENEA C.R. Brasimone to perform deterministic safety investigation of such accidental scenario. Thanks these modifications, this version of the code has unique features for dealing with the PbLi water reaction related phenomena. The reliability of the code requires a systematic validation activity, carried out applying a standard methodology based on a three-steps procedure and through qualitative and quantitative evaluations. The methodology was applied to the LIFUS5 campaign. Post-test analyses highlighted open issues of test execution and of experimental data, as well as code limitations and capabilities. Nevertheless, the modified version of SIMMER-III code for fusion application is able to predict the relevant thermal-hydraulic phenomena during PbLi/water interaction.