TRAC-PF1/MOD1 independent assessment. LOBI intermediate break test B-R1M

The TRAC-PR1/MOD1 independent assessment project at Sandia National Laboratories is part of an overall effort funded by the NRC to determine the ability of various system codes to predict the detailed thermal/hydraulic response of LWRs during accident and off-normal conditions. The TRAC code is being assessed at SNLA against test data from various integral and separate effects test facilities. As part of this assessment matrix, two approx.25% intermediate break counterpart tests, B-RIM performed at the LOBI facility and S-IB-3 performed at the Semiscale Mod-2A facility, have been analyzed. The LOBI B-RIM results show that no core heatup was measured, and none was calculated; there are some differences between calculated results and data, but generally the agreement is good. Comparison of our LOBI results with corresponding results from our analyses of the counterpart test S-IB-3 show that similarities and differences in most of the major phenomena were correctly predicted. 19 refs., 46 figs