Abstract:
The nuclear accidents at the Three Mile Island, Chernobyl, and Fukushima Daiichi nuclear power plants were the three most severe accidents in the history of nuclear power. These accidents brought about an unavoidable adverse impact on humans and the environment. The issue of nuclear power plant safety has become the top priority for the technology developer and the current user countries but also for the new countries currently planning or building new nuclear power plants. For this reason, some research works related to the safety of nuclear power plant has been initiated and implemented in Thailand. In this study, the prediction capability of RELAP/SCDAPSIM/MOD3.4 developed by Innovative Systems Software (ISS) is being assessed using the Severe Fuel Damage (SFD) Test 1-4 performed in the Power Burst Facility (PBF) at the Idaho National Engineering Laboratory. The objective of this work is to evaluate the effectiveness of RELAP/SCDAPSIM/MOD3.4 to predict severe core behavior, fission product release and hydrogen generation rates during 1.3 hours transient. The calculated results were compared to the available experimental data and the calculated results from the SCDAP/RELAP MOD1, MOD3.2 and MOD3.3. In general, the obtained results indicated that RELAP/SCDAPSIM MOD3.4 predicted reasonably well the experimental data and is more accurate than the SCDAP/RELAP MOD1, MOD3.2 and MOD3.3 prediction. Even though, some discrepancies, especially in the cladding temperatures during the beginning phase, were found from the comparison of the calculated results and test data, these discrepancies were due to the uncertainties in the boundary conditions and code nodalization.