RELAP5 assessment: Semiscale natural-circulation tests S-NC-2 and S-NC-7. [PWR]

The RELAP5 independent assessment project at Sandia National Laboratories in Albuquerque (SNLA) is part of an overall effort funded by the US Nuclear Regulatory Commission (NRC) to determine the ability of various systems codes to predict the detailed thermal/hydraulic response of LWRs during accident and off-normal conditions. This report summarizes the RELAP5 analyses of two particular series of Semiscale natural circulation tests. The RELAP5 models used for the analyses are described. The calculational results for tests S-NC-2 and S-NC-7 are presented. The overall conclusions and their possible relevance to future RELAP5 code application and development are discussed. The appendices provide a brief description of the test facility, and input listings for the transients, for reference.