Load-Follow Operation in LEU+ loaded very-low soluble boron APR1400

This study explores the effectiveness of the mode-K+ strategy in managing a Very-Low Soluble Boron (VLSB) APR1400 core, loaded with LEU + fuel, and utilizing the Centrally-Shielded Burnable Absorber (CSBA) and erbia for excess reactivity control. Initially, a 24-month two-batch fuel management scheme was developed, targeting an equilibrium cycle Burnup (BU) of 26 GWD/MTU. The scheme required a maximum of ∼550 ppm Critical Boron Concentration (CBC) in the early cycle BU. Analysis of radial and axial power profiles revealed that the power peaking factors remained within acceptable limits, with values not exceeding 1.4 and 1.6 throughout the cycle, respectively. Subsequently, various Daily Load-Follow Operation (DLFO) scenarios were examined at different BU levels. These investigations demonstrated a consistent alignment between the demanded power and the reactor's power output. Furthermore, critical safety parameters, including the Axial Shape Index (ASI) and inlet coolant temperature, consistently remained within prescribed design specifications. The study's findings underscore the feasibility and reliability of implementing a VLSB APR1400 core with LEU + fuel, using mode-K+ and advanced fuel management strategies for effective power generation and safety compliance. To perform the analysis, an in-house diffusion code KANT was utilized, KANT is based on NEM-CMFD accelerated simulation tool, while the cross-section was generated via Serpent 2.2.0 assessed with ENDF VII.B data library.