Analisis of Surge Line MBLOCA Sequences With HPSI Failed

Abstract

The main objective of OECD/NEA ROSA-2 Project is to analyze thermal-hydraulic issues relevant to light water reactors (LWR) safety by using Large Scale Test Facility (LSTF) . As a part of this project ROSA-2 test1 has been performed in LSTF during 2009. This test consists of a double ended guillotine break in the surge line, surge line loss-of-coolant accident (SL-LOCA), with high pressure safety injection, (HPSI) failed and reactor coolant pumps trip simultaneously to reactor scram. As part of the participation of Universidad Politécnica de Madrid (UPM) group in OECD/NEA ROSA-2 and Code Applications and Maintenance Program (CAMP) projects two tasks related with this test have been performed. In the first task the simulation of ROSA-2 test1 has been performed with TRAC/RELAP Advanced Computational Engine (TRACE) code. Furthermore, an analysis of similar sequences in a Westinghouse pressurized water reactor (PWR) has been carried out; within this analysis a wide range of break area size has been analyzed: from 0.0254 m to 0.2794 m (1" to 11"), and a sensitivity analysis of delay time in the beginning of manual depressurization in the secondary side has been performed. The results show that the sequences with intermediate break sizes, from 0.0508 m to 0.1016 m (2" to 4") have worse consequences in this kind of sequences.