Evaluation of reflood HTC and CRF of RELAP5/MOD3.1/K for the new LOCA M/E analysis

The New LOCA Mass and Energy (M/E) release analysis methodology has been developed by coupling two computer codes, RELAP5/MOD3.1/K for the RCS thermal hydraulic analysis and CONTEMPT4/MOD5 for the containment back pressure analysis. During the development, review and comparison of regulations for equipment qualification, domestic and international status of relevant techniques, and thermal hydraulic models of the best-estimate codes were necessary to assure its compliance with current regulation. Especially, major modeling parameters which affects most the analysis results should be carefully evaluated from the licensing viewpoint. In this paper, reflood Heat Transfer Coefficient (HTC) and Carryover Rate Fraction (CRF) among various main parameters are selected, simulated, and compared with the experimental data of the FLECHT (Full Length Emergency Cooling Heat Transfer) facility to assess the applicability of RELAP5/MOD3.1/K to the new LOCA M/E release analysis