Calculation chain for the analysis of spent nuclear fuel in long-term interim dry storage

In this paper, a calculation chain for the analysis of spent nuclear fuel in long-term interim dry storage is demonstrated. The calculation chain consists of reactor physics burnup simulation for obtaining the decay heat, Computational Fluid Dynamics (CFD) simulation for the temperatures of fuel rods and the dry storage cask, and finally, cladding integrity analysis. Each succeeding calculation step uses the results from the previous step as boundary conditions. The applied codes are Serpent Monte Carlo reactor physics burnup code, open-source OpenFOAM CFD code, and VTT-ENIGMA fuel performance code. The peak cladding temperatures are calculated with OpenFOAM at different instants of time, ranging from 3.4 to 300 years after unloading from the reactor. The chosen demonstration case considers 17x17 PWR fuel stored in a CASTOR® V/21 type dry storage cask. The main parameters of interest in the last stage of the analysis are the cladding creep hoop strain and stress during dry storage. The developed analysis methodology helps to ensure the safety of long-term dry storage.