Abstract
MAAP5 is an integral severe accident analysis program which simulates the responses of light water reactor power plant during severe accident. The program has been used intensively in the framework of probabilistic safety assessment, verification and validation of mitigation actions specified in the severe accident management guidelines (SAMG), and source term quantification. In the present study, a methodology is developed to quantify the uncertainties of model parameter of MAAP5. The target output parameters analyzed is the in-vessel hydrogen production during a core melt accident. The surrogate plant analyzed is Lungmen Nuclear Power Station of Taiwan Power Company. The plant employs Advanced Boiling Water Reactor (ABWR). Sensitivity studies are performed to identify the important model parameters which have impact on the target output parameter. Range and distribution are assigned to these parameters based on experiment results and expert judgement. Multiple calculations of MAAP5 are performed with input combination generated from Latin Hypercube Sampling (LHS). The results of the calculations are analyzed parametrically and non-parametrically to determine the 95 th percentile with 95% confidence level value of the amount of in-vessel hydrogen production. The Pearson Correlation Coefficient (PCC) was used to determine the impact of model parameters on the target output parameters. The results of the analyses provide guidance for the code applications.