Sensitivity and Uncertainty Analysis of Neutron Spectrum and DPA in a B&B Core

Abstract

This study quantifies the uncertainty in the calculated displacements per atom (DPA) value due to uncertainties in the neutron spectrum resulting from cross-section data uncertainty. Using generalized perturbation theory, covariance matrices, and fine-group DPA cross sections, a method for propagating nuclear data uncertainties through to the calculation of DPA is outlined. This method is then implemented for the case of a typical sodium-cooled breed-and-burn core. The majority of uncertainties in accumulated DPA were found to come from the inelastic scattering cross section for ²³⁸U. Overall the uncertainty in accumulated DPA is found to be roughly 2% of the total value.

Keywords:

• Displacements per atom
• sensitivity
• uncertainty
• breed-and-burn
• generalized perturbation theory

Acknowledgments

This research used the Savio computational cluster resource provided by the Berkeley Research Computing Program at the University of California, Berkeley.