EXPERIMENTAL INVESTIGATION ON DRYOUT PHENOMENON OF HOMOGENEOUS AND AXIAL STRATIFIED DEBRIS BED

抄録

The dryout behavior of debris bed is an important safety issue in the postulated Core Disruptive Accidents (CDAs) of a sodium-cooled fast reactor. In this paper, the coolability of debris beds is studied experimentally and quantitatively assessed by the dryout heat flux (DHF). Dryout phenomenon of three cases with different particle diameter of 1mm, 2mm and 3mm and two cases of axial stratified beds are investigated. And the dryout location is monitored by the sudden rise in temperature and observed by visualization. The mechanism of the dryout behavior of axial stratified beds is discussed. Results show that the dryout location of homogeneous bed occurs at the bottom of the debris bed, while the dryout location of the axial stratified debris bed with different stratified mass ratio is found at the interface and then expands downward. The DHF of axial stratified bed is about 10% of that of the homogeneous debris bed packed with small particles of the same size at the upper layer of axial stratified bed, because of the low permeability at the interface.