A Batch Refueling Framework for Implementing the Sourdough Fuel Cycle and Waste Management Strategy in the EIRENE Novel Molten Salt Reactor Design

Public perception of nuclear power continues to be hindered by the challenge of used fuel management. Advanced Generation IV reactor designs such as the Molten Salt Reactor (MSR) could potentially serve a significant role in high-level waste (HLW) minimization and management, with innovative fuel cycles warranting further study as commercial interest in these reactors continues to increase. In particular, the Sourdough refueling and waste management strategy has recently been proposed as a promising alternative fuel cycle for thermal spectrum MSRs operating with low-enriched uranium (LEU). The Sourdough concept has demonstrated promise in recent research as an efficient framework for minimizing and managing HLW in addition to supporting flexible nuclear fleet growth and grid decarbonization. In this work, the Sourdough refueling strategy will be implemented into a novel thermal spectrum LEU-fueled MSR design. The SCALE/KENO-VI Criticality Safety Analysis Sequence (CSAS6) will be used to study reactivity feedback and neutron flux behavior, while a combination of KENO-VI and TRITON will be used for implementation of the Sourdough refueling framework. Changes in reactivity resulting from different refuel enrichment levels and refuel volume additions will be examined for each depletion step with the objective of determining optimal refueling regimes for maintaining reactor safety and criticality, in addition to achieving a desired rate of fuel growth. Furthermore, the MSR model, in addition to all scripts developed for implementing and analyzing the Sourdough refueling strategy, is open source and made freely available with the intent of fostering continued growth in MSR fuel cycle research.