Experiments and procedures for bottom heating heat transfer experiments through UO2 debris beds in sodium

Heat transfer to sodium without presence of debris showed that 153 watts/cm2 could be transferred before filament failure was encountered. This demonstrated that adequate capacity existed to dryout debris beds. For subcooled pool conditions, dryout heat fluxes ranged from 33.1 to 46.3 Watts/cm2. The measurements did not show any strong dependence upon the degree of subcooling. Dryout heat fluxes using the ANL procedure of bed loading were obtained for subcooling of 269 and 5650C. The measured heat fluxes are comparable to values determined in previous experiments in which bottom heating with gas flames was employed. Test have been performed to determine the effect of the method of bed loading on dryout. (DG)