Evaluation of RELAP5/MOD3 behavior against loss of flow experimental results from two research reactor facilities

This study presents the simulation results of LOFA experiments for two research reactor facilities; namely the Indonesian (RSG-GAS) and Egyptian (ETRR-2) Research Reactors. The RSG-GAS reactor is equipped with two Instrumented Fuel Elements capable of providing cladding temperature indications, whereas ETRR-2 provides temperature measurements in different positions above the core. The RELAP5/MOD3.3 code is used to simulate the system response under these transients and estimate a number of measured parameters – including the cladding temperature for the RSG-GAS reactor. The main objective of this analysis is to examine, through detailed modeling, the code response and compare it with experimental measurements under loss of flow conditions in research reactors. In this framework the introduction of two novel metrics that quantify aspects of the model behavior is also discussed. The results obtained confirm the applicability of RELAP5/MOD3.3 on the modeling of loss of flow analysis in research reactors and contribute toward the adoption of metrics as application performance measures.