ICONE19-43273 INVESTIGATION OF CRITICAL HEAT FLUX IN THE ROD BUNDLE USING MECHANISTIC APPROACH IN CONJUNCTION WITH THE SUBCHANNEL CODE

Abstract

Critical Heat Flux (CHF) is one of the important parameters for the thermal design of a rod bundle. Subchannel analysis is recommended in the absence of experimental data to determine the thermal margin of a new fuel design using empirical correlations. However, there are a large number of empirical CHF correlations available even for a simple geometry which indicates that a generic correlation with wide range of validity is not available in the literature and hence mechanistic approach could be more appropriate. A mechanistic model based on the Liquid Film Dryout approach with the constitutive models suitable for the BWR conditions have been employed in conjunction with the subchannel code COBRA-IIIC. This paper deals with the film dryout analysis of a typical BWR fuel bundle considering a simplified mechanistic approach in conjunction with the subchannel code.