Assessment of the COBRA/RELAP5 code using the LOFT L2-3 large-break loss-of-coolant experiment

The COBRA/RELAP5 code, a merged version of COBRA-TF and RELAPS/MOD3 SmS, was upgraded with RELAP5/MOD3.2. Using the "inter-process communication" technique, the realistic three-dimensional reactor vessel module of CIBRA-TF was linked with the RELAPS code in the merged code. The three-dimensional capability of COBRA/RELAPS was assessed using the LOFT L2-3 large-break loss-of-coolant accident (LOCA) experimental data. The evaluate the overall performance of the code, relatively fine three-dimensional meshes were used for the reactor vessel, which was simulated by CIBRA-TF, and the other systems were one-dimensionally modeled by RELAP5/MOD3.2. The simulation results showed that COBRA/ RELAPS is a promising tool for analysis of complicated, multidimensional, two-phase flow transients in pressurized water reactors (PWRS).