Angular distribution uncertainty influence in a large sodium-cooled fast reactor with mixed-oxide fuel

Nuclear data uncertainties are considered a main limiting factor in proving safety of advanced reactors. A reasonable amount of available information should be applied to sensitivity and uncertainty analyses for this, and this work considers the influence of usually omitted angular distribution uncertainties. A sensitivity and uncertainty analysis of MOX3600 is conducted using Serpent. The angular distribution influence is assessed by applying covariances of the state-of-the-art libraries. The sensitivity analysis shows that quantifying the influence of higher-order Legendre moment uncertainties on the eigenvalue and void reactivity is of minor importance for MOX3600. The uncertainty analysis shows the P1-coefficients for 238U and 16O introduce uncertainties to the eigenvalue similar to 56Fe and should be accounted for. A library comparison reveals TENDL-2021 and ENDF/B-VIII.0 introduce uncertainties of a few hundred pcm to the eigenvalue, and the data should be reassessed, while the other libraries give an uncertainty of several tens of pcm.

Automated summary

This paper analyzes the impact of nuclear data uncertainties on the safety of advanced reactors, with a specific focus on angular distribution uncertainties. Through sensitivity and uncertainty analysis, key parameters for MOX3600 are identified, and a comparison of different libraries' uncertainties on the eigenvalue is performed.