A COMBINED PROCEDURE OF RSM AND LHS FOR UNCERTAINTY ANALYSES IN-SOURCE TERM QUANTIFICATIONS USING MAAP3.0B CODE

Quantification of uncertainties in the source term estimations by a la rge computer code, such as MELCOR and MAAP, is an essential process of the current probabilistic safety analysis. The main objective of the present study is to investigate the applicability of a combined proced ure of the response surface method (RSM) based on input determined fro m a statistical design and the Latin hypercube sampling (LHS) techniqu e for the uncertainty analysis of Csl release fractions under a hypoth etical severe accident sequence of a station blackout at Young-Gwang n uclear power plant using MAAP3.0B code as a benchmark problem. On the basis of the results obtained in the present work, the RSM is recommen ded to be used as a principal tool for an overall uncertainty analysis in source term quantifications, while using the LHS in the calculatio ns of standardized regression coefficients (SRC) and standardized rank regression coefficients (SRRC) to determine the subset of the most im portant input parameters in the final screening step and to check the cumulative distribution functions obtained by RSM. Verification of the response surface model for its sufficient accuracy is a prerequisite for the reliability of the final results that can be obtained by the c ombined procedure proposed in the present work. Copyright (C) 1996 Els evier Science Ltd