Simulation of pressure waves propagation following LOCA in piping systems using Laplace Transform Finite Volume

摘要

The detailed dynamic modeling and the simulation of the rapid depressurization of PWR following leak or loss of coolant accident, LOCA, is a key element of the safety analysis in the nuclear power plants. Early in a LOCA, the blowdown at the break point causes the propagation of an acoustic wave through the primary circuit. The local pressure gaps due to the depressurization wave propagation may lead to the component recoils and the internal structure movements. In this paper to obtain the pressure depressurization rate behavior in hypothetical LOCA, a thermal hydraulic test loop, THTL facility, has been designed and constructed. The pressure change data are provided to model the trend of the pressure decreasing along the water hammer oscillation peaks that are produced as soon as the accident is initiated. For determination of the intensity of the water hammer pressure waves due to LOCA, the governing equation is solved using Laplace Transform Finite Volume, LTFV, method and the boundary conditions are set on using the obtained experimental data from the THTL facility.To evaluate the method, the analysis of the water hammer data which is obtained experimentally from THTL facility are compared with simulation results of LTFV technique which reveals the reliability of the method. (C) 2018 Elsevier Ltd. All rights reserved.