BURFEL BIAS AND MCNP BENCHMARKING BURFEL CALCULATIONS OF NRU LOOP FUEL

Abstract

The Burnup of Fuel Elements (BURFEL) code system has been used to calculate powers and burnups for experimental fuel irradiated in the National Research Universal Reactor (NRU) loops. BURFEL-calculated burnups, based on the calorimetrically measured loop powers, have been observed to exhibit biases with respect to their chemically measured counterparts. A high-fidelity Monte Carlo N-Particle method involving the NRU full-core model has been used for benchmarking BURFEL calculations, resulting in similar biases attributed to uncertainties in the loop powers. This study provides quantitative insights into the observed BURFEL biases for the purpose of possibly correcting existing loop fuel irradiation data for such biases.