Sensitivity and uncertainty analysis of the VENUS-F critical core

A sensitivity and uncertainty analysis was performed for a critical configuration at he VENUS-F facility using three major nuclear data libraries (JENDL-4.0, ENDF/B-VII.1, and JEFF-3.1.2) and the JENDL-4.0 covariance data. Differences in keff between the nuclear data libraries are shown to be smaller than those between the geometric models/calculation methodologies. Both the diffusion and transport methodologies in the criticality calculation provide similar results for the differences in keff between JENDL-4.0 and ENDF/B-VII.1 (∼450 pcm) and etween JENDL-4.0 and JEFF- 3.1.2 (∼270 pcm). Major contributors to these differences are identified along with sensitivity coefficients. Among nuclear data parameters, the keff of the VENUS-F core is sensitive to the fission cross section, fission neutron multiplicity, and capture cross section of uranium as well as the elastic scattering parameters of lead and 56Fe. It was found that these parameters have a considerable impact on the differences in keff. However, their positive and negative elements cancel each other out, thereby resulting in a relatively small difference. Based on the JENDL-4.0 covariance data, the total uncertainty induced by the nuclear data is evaluated to exhibit a 0.833% δk/k (1σ).