Two Batch Fuel Management for the Soluble Boron Free ATOM Core

To accomplish these requirements, SMRs should be compact, simple and less dependent on active control components. From this point of view, for pressurized water reactor (PWR) type SMRs with soluble boron free (SBF) coolant is favorable because the use of borated coolant has following drawbacks: 1) acceleration of material corrosion 2) radioactive liquid waste 3) positive moderator temperature coefficient, 4) complicated chemical volume control system (CVCS). In previous work, a 450MWth SBF SMR based on PWR type, namely autonomous transportable on-demand reactor module (ATOM), has been studied, aiming at extremely safe SMR with autonomous operation capability. To eliminate the soluble boron from the coolant without any degradation of the safety or performance, a new burnable absorber (BA) design, centrally-shielded burnable absorber (CSBA) was introduced and its neutronics feasibility of using a single batch fuel management was evaluated using optimized CSBA loading scheme. The main purpose of this study is to evaluate the feasibility of two-batch fuel management in the ATOM core operation to enhance the fuel utilization. All the neutronics calculations are carried out using Monte Carlo code SERPENT2 in conjunction with ENDF/B-VII.1. To achieve higher discharged burnup compared to previous single batch ATOM core design, the feasibility of applying 2-batch fuel management to the core was evaluated in this study. Noticeable improvement in discharge burnup with marginal reactivity penalty was observed using 2-batch fuel management in the ATOM core.