Subchannel analysis of a critical power test, using simulated BWR S × S fuel assembly

Abstract Critical power predictions have been compared with the critical power test data obtained in simulated BWR 8 × 8 fuel rod assemblies. Two analytical methods for the critical power prediction in rod assemblies are used in the prediction, which are the subchannel analysis using the COBRA/BWR subchannel computer code with empirical critical heat flux (CHF) correlations and the liquid film dryout estimation using the CRIPP-3F ‘multi-fluid’ computer code. Improvements in both the analytical methods were made for spacer effect modeling, though they were specific for application to the current BWR rod assembly type. In general a reasonable agreement was obtained, through comparisons, between the prediction and the obtained test data.