Analysis of VVER-1000 Large and Small Break LOCA Experiments With RELAP5/MOD3.2

A RELAP5 model for the analysis of the PSB-VVER test facility was developed by the EREC in Russia. The PSB-VVER is a large-scale integral test facility to model the VVER-1000 type NPP. The volume and power scale in this test facility is 1:300 and the elevation scale is 1:1, which corresponds to the elevation mark of the reactor prototype. At the Division of Nuclear Safety, RIT, Sweden, we have modified the PSB-VVER facility’s RELAP5 model in order to analyze two of the transient tests performed on the PSB-VVER facility, which serve as the validation matrix described by NEA/CSNI. The objective of the work conducted was to validate the results obtained from RELAP5’s calculation with the supplied experimental data from the PSB-VVER test facility. Two accident scenarios have been calculated and analyzed. After being verified against the “11% UP LOCA” test data, the RELAP5/MOD3.2 model was used for a so-called “blind” transient calculation of the test “2×25% HL LOCA” and the results obtained were compared with the experimental data provided after the calculation.