Evaluation of neutronic characteristics of accident tolerant fuel concepts in SMART reactor fuel assemblies using DRAGON

Abstract

The selection of perfect accident-tolerant nuclear reactor fuels necessitates a neutronic study of the various fuels for Small Modular Reactors (SMRs). This study demonstrates a neutronic assessment of 17 × 17 fuel assemblies of Korean SMART (System-Integrated Modular Advanced ReacTor) integral type SMR using three types of Accident Tolerant Fuel (ATF) by the deterministic code DRAGON. These reactors are less expensive to build, have a shorter construction period, are safer, and have a higher power density. Uranium Nitride (UN), Uranium Di-Silicide (U3Si2), and Composite material (70 % UN- 30 % U3Si2) are considered the most potential ATF candidates. The effective multiplication factor (keff), different fissionable materials, neutron poisons, neutron-induced power, decay power, and fuel burnup are investigated as well as presented on graphs and compared from the conventional fuel UO2. Throughout the entire duration of the operation, all four models maintain a critical state while maintaining consistent dimensions. However, due to enrichment and chemical composition differences, it is found that the UN has the highest keff value. UN displayed lower concentration variation for different isotopes, whereas UO2 showed the highest power analysis study among the models. The different approaches to Accident Tolerant Fuel are not quite significant. However, opting for Uranium Nitride (UN) could offer a slight advantage in terms of effectiveness because of the higher power-up rates and burnup as well as increased cycle length when compared to the other three options.