Experimental study of the influence of cross-overflow on the decay heat removal from spent fuel pools

Abstract

In the case of failure of cooling systems or structures in spent fuel pools (SFP), the decay heat removal must be guaranteed to prevent a fission product release. The heat, generated by the fuel assemblies (FA), causes a water level decrease, when heat removal systems fail. In this case, the cooling of the inventory is no longer guaranteed. If limit temperatures are exceeded, an irreversible damaging of the fuel assemblies is possible. To predict the decay heat removal for different accident scenarios, the project SINABEL was initiated. Within this project, the test facility ALADIN was erected in 2016 at TU Dresden to analyze cladding temperature profiles in beyond design accident scenarios. An additional overflow channel was equipped to the ALADIN test facility in order to investigate the influence of air cross overflow on the decay heat removal for different rod powers and overflow velocities in SFP boil-off and air cooling scenarios. To provide an overview of the application field of the test facility, all planned experiments are briefly presented. The results of the first experiments indicate an influence of the overflow on the surface temperatures of the FAs. Finally, conclusions for the safety of SFPs are drawn.