Benchmarking NSP Reactors with CORETRAN-01

As part of an overall verification and validation effort, the Electric Power Research Institute's (EPRIs) CORETRAN-01 has been benchmarked against Northern States Power's Prairie Island and Monticello reactors through 12 cycles of operation. The two Prairie Island reactors are Westinghouse 2-loop units with 121 asymmetric 14 × 14 lattice assemblies utilizing up to 8 wt% gadolinium while Monticello is a General Electric 484 bundle boiling water reactor. All reactor cases were executed in full core utilizing 24 axial nodes per assembly in the fuel with 1 additional reflector node above, below, and around the perimeter of the core. Cross-section sets used in this benchmark effort were generated by EPRI's CPM-3 as well as Studsvik's CASMO-3 and CASMO-4 to allow for separation of the lattice calculation effect from the nodal simulation method. These cases exercised the depletion-shuffle-depletion sequence through four cycles for each unit using plant data to follow actual operations. Flux map calculations were performed for comparison to corresponding measurement statepoints. Additionally, start-up physics testing cases were used to predict cycle physics parameters for comparison to existing plant methods and measurements.

These benchmark results agreed well with both current analysis methods and plant measurements, indicating that CORETRAN-01 may be appropriate for steady-state physics calculations of both the Prairie Island and Monticello reactors. However, only the Prairie Island results are discussed in this paper since Monticello results were of similar quality and agreement. No attempt was made in this work to investigate CORETRAN-01 kinetics capability by analyzing plant transients, but these steady-state results form a good foundation for moving in that direction.