SANTA: A safety analysis code for neutron absorbers in spent nuclear fuel pools

Abstract

Recent experimental reports on the premature corrosion of an Al-B4C neutron absorber in a spent nuclear fuel pool, which was possibly assisted by 10B(n, α)7Li reaction-induced porous microstructures, illustrated the need for quantitative evaluation of the neutron-induced energetic particle emission reactions inside neutron absorbers. For this purpose, we developed a Safety Analysis code for NeuTron Absorbers in spent nuclear fuel pools (SANTA) by integrating several existing codes (TRITON, ORIGEN, CSAS6, and modified SDTrimSP) with newly developed modules to provide the essential parameters for the experimental emulation of irradiation-assisted corrosion of the absorbers. The most important outputs of this code are radiation damage in displacement per atom (dpa) units and He concentration in atomic ppm. These outputs are required for the design of heavy-ion irradiation experiments on the absorbers to emulate the radiation damage induced by energetic 7Li ions and α-particles. The SANTA code is also user-friendly: its whole sequence can be executed using simplified text-based input without user intervention. This code may improve the understanding of the gas bubble formation and irradiation-assisted corrosion mechanisms of the neutron absorbers, and it could provide a foundation for the future development of more robust safety codes for spent nuclear fuel pools.