Validation of the Serpent-ARES code sequence using the MIT BEAVRS benchmark - Initial core at HZP conditions

The Serpent-ARES code sequence, applying Monte Carlo based group constants in a full-core nodal diffusion calculation, is currently being validated for PWR fuel cycle simulations. The test case chosen for the task is the MIT BEAVRS benchmark, which provides a detailed description of a commercial PWR core, including operating data and results of experimental measurements. This paper summarizes the first stage of the validation study, which is focused on the neutronics solution at the hot zero-power state of the initial core. The results show a good agreement between the ARES simulation and a reference full-scale Monte Carlo calculation at both assembly- and pin-level. At core mid-plane, the reconstructed pin-powers are off by less than 1% in 82% of all fuel pins.