Accident analysis of spent fuel storage and transportation cask with gd based neutron absorber

Abstract

The shortage of nuclear spent fuel storage pool has been issued. The spent fuel storage and transportation cask is one of the major alternatives for storing spent fuel. The use of advanced neutron absorber is important for effective storage of spent fuel in spent fuel cask. Gadolinium based neutron absorber is chosen since it has high neutron absorption cross section in thermal neutron region compared to boron and it does not produce any gas element when it reacts with a neutron. The major requirement for neutron absorbing materials in the spent fuel cask system is to maintain subcriticality in normal, off-normal and accident conditions. In this study, the criticality calculations under accident conditions are conducted to ensure the safety of spent fuel cask. Major accident conditions are flood and cask tip-over. The full and partial flooded condition is analyzed and 100% flooded condition has the highest reactivity. The water density is selected as 1 g/cm3 because keff is highest at this condition. When the cask tip-over, the flux trap reduces. In this case, a huge increase in reactivity of 800 pcm.