Applying the continuous-energy Monte Carlo calculation code, MVP3, to analysis of kinetic parameters measured for light-water moderated UO₂ and MOX cores of the TCA and EOLE critical facilities

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 (<i>β_eff</i>) to prompt-neutron life time (<i>ℓ</i>) – represented hereafter by <i>β_eff</i>/<i>ℓ –</i> and <i>β_eff</i> 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 <i>β_eff</i>/<i>ℓ</i> 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 <i>β_eff</i> of one UO₂ core in TCA, C/E − 1 was 1.2%. For the <i>β_eff</i> 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 <i>β_eff</i> 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.