TOPFLOW-PTS Experiments. Pre-Test Calculations with NEPTUNE_CFD Code

Abstract

Hypothetical Smal l Break Loss Of Cool ant Acc ident is identified as one of the most severe transients leading to a potential huge Pressurized Thermal Shock on the Reactor Pressure Vessel (RPV). T his m ay result in two-phase fl ow configurations in the co ld legs, according to the operating condi tions, and to reliabl y assess t he RPV wall int egrity, advanced t wo-phase flow simulations are required. Related n eeds in de velopment and/ or validation of t hese advanced models are important, and the on-going TOPFLOW-PTS experimental program was designed to provide a well docum ented data base to m eet th ese needs. This pap er focuses on pre-test NEPTUNE_CFD simulations of TOPFLOW-PTSexperiments; these simulations were performed to (i) help in the definition of t he test matrix and test procedure, and (ii) check t he presence of the different key physical phenomena at the mock-up scale.