An experimental study on the coolability of stratified debris beds

摘要

Coolability of a debris bed is a real concern and hence it is receiving attention a part of ongoing in severe accident research. Many experimental and analytical studies have been done in order to enhance the quantitative understanding of the debris bed coolability. The present paper deals with an experimental investigation of multi-dimensional stratified bed and the horizontally stratified bed, which is the extension of our previous study on the radially and triangularly stratified beds. These stratified beds are composed of different zones/layers of various particle diameters and porosities, where the stainless steel spheres are used. These tests are carried out on the POMECO-HT facility built at KTH, Sweden. The dryout heat flux obtained for above specified beds helps to study the effect of multi-dimensional coolant ingression on coolability of the beds. All the experiments are carried out under top-flooding conditions at first. Afterwards, the use of a down-comer is installed in order to investigate study the effect of external natural convection driven coolability (NCDC) on dryout heat flux of the beds.