LAUSR

ABSTRACT In order to evaluate the accuracies of the kinetics parameters predicted with the continuous-energy Monte Carlo calculation code, MVP3, core analysis was performed for light-water moderated UO2 and mixed oxide (MOX) fuel cores for which the ratios of effective delayed-neutron fraction (βeff ) to prompt-neutron life time (ℓ) – represented hereafter by βeff /ℓ – and βeff values were measured. The results obtained with the JENDL-4.0-based neutron library showed that (the calculation values (C)/the measurement values (E)−1) ranged from −1.0% to 4.0% for the βeff /ℓ values with an average of 1.0% and a standard deviation of 1.1% for the 17 cores (the UO2, and UO2-MOX mixed cores) tested in the Tank-Type Critical Assembly (TCA). With respect to the βeff of one UO2 core in TCA, C/E − 1 was 1.2%. For the βeff values of the UO2 and MOX cores tested in the EOLE critical facility, C/E − 1 was −1.5% for the former and −4.6% for the latter. The calculated βeff value of the MOX core using the JEFF-3.2-based neutron library was larger by 4% than that calculated using the JENDL-4.0-based neutron library and showed better agreement to the measurement.