Estimation of Self-shielding Effect on Uncertainty of Neutronics Characteristics using Random Sampling Method and Continuous-energy Slowing-down Calculation

摘要

The effect of self-shielding of cross sections on the uncertainty of neutronics characteristics is evaluated by the random sampling method and the resonance calculation based on the ultra-fine group spectrum calculation. The calculation results indicate that the self-shielding effect has impact on the estimation results of uncertainty of k-infinity. The effect of self-shielding on the uncertainty of k-infinity depends on a nuclide in focus. In the present study, uncertainty due to ~(238)U capture cross section is sensitive to the treatment of self-shielding. When the self-shielding effect is taken into account, estimated uncertainty of k-infinity decreases by approximately 6%.