THERMAL-HYDRAULIC EVALUATION OF AN LBE COOLED 19-PIN BUNDLE IN THE FRAME OF TRACE VALIDATION

摘要

In the frame of the validation and verification of the thermal hydraulic system code TRACE for lead alloy cooled systems, a 19 pin bundle is analyzed, in particular, the influence of the spacers. TRACE is updated and improved in order to be used for the analyses of liquid metal cooled reactors. For the present investigation, isothermal hydraulic experiments, carried out at the Karlsruhe Lead Laboratory, are used to validate the pressure losses related to wall friction and spacers. In this experimental set-up, a 19 rod bundle, cooled by liquid lead-bismuth eutectics (LBE) is used. In addition, thermal analyses are performed in order to evaluate the axial temperature profile of coolant and cladding and to validate the chosen heat transfer models. Since the thermal experiments have not been performed yet, the validation is done by comparing TRACE results to CFD results following a unique approach for the turbulent Prandtl number. Special emphasize is paid to the validation of the models to account for heat transfer enhancement at and in the vicinity of spacers due to increased turbulences.