Investigation of WWER-type and PWR-type model fuel assemblies quenching during loss-of-coolant accident

The results of reflooding investigations of WWER-type and PWR-type model fuel assemblies (FA) carried out at large-scale facilities (RBHT, SVD, PARAMETER) under Design Basis Accident (DBA) and Beyond Design Accident (BDA) conditions are presented. The regime parameters ranges are: the initial fuel rod temperature - T_clad = 460÷1600 °C, water mass rate - ρw = 47÷160 kg/(m²·s), FA inlet subcooling - ΔT_sub= 11 - 118 °C, pressure - p=0,14÷0,42 MPa and the linear heat flux density simulating decay heat - ql = 0÷2,3 kW/m. The generalizing correlation on the quench front velocity of model FA´s describing the experimental data with 30% error is proposed. It allows to predict the latency of model fuel assemblies reflooding of various design and to evaluate the time of WWER and PWR reflooding.