Experimental investigation on dryout heat flux of a particle debris bed with a downcomer

This paper presents the results of experimental investigation on dryout heat flux of a particulate debris bed. A series of experiments on the POMECO (porous media coolability) facility were performed for both homogeneous and stratified heated porous beds. The porous beds were made of different sand particles. The porosity of particle bed was varied from 25 to 40%, and the average particle size from 0.2 to 1 mm. Experimental results for the dryout heat flux of homogeneous beds with top flooding compare well with the predictions by Lipinski correlation. For the stratified particle beds, the fine particle layer resting on the top of another particle layer is found to dominate the dryout processes. The effect of a downcomer on the dryout heat flux was also investigated for both homogeneous and stratified particle beds. It was found that the downcomer can enhance the dryout heat flux from 50 to 350%. (orig.)