Uncertainty Analysis of the TRU-Burning Thorium-Fueled RBWR Using Generalized Perturbation Theory

Abstract

TitleUncertainty analysis of the tru-burning thorium-fueled rbwr using generalized perturbation theory ABSTRACTThe RBWR-TR is a thorium-based reduced moderation BWR (RBWR) with a high transuranic (TRU) consumption rate. It is charged with LWR TRU and thorium, and it recycles all actinides an unlimited number of times while discharging only fission products and trace amounts of actinides through reprocessing losses. This design is a variant of the Hitachi RBWR-TB2, which arranges its fuel in a hexagonal lattice, axially segregates seed and blanket regions, and fits within an ABWR pressure vessel. The RBWR-TR eliminates the internal axial blanket, eliminates absorbers from the upper reflector, and uses thorium rather than depleted uranium as the fertile makeup fuel. This design has been previously shown to perform comparably to the RBWR-TB2 in terms of TRU consumption rate and burnup while providing significantly more margin against critical heat flux.This study examines the uncertainty in key neutronics parameters due to nuclear data uncertainty. As most of the fissions are induced by epithermal neutrons and since the reactor uses higher actinides as well as thorium and 233 U, the cross sections have significantly more uncertainty than in typical LWRs. The sensitivity of the multiplication factor to the cross sections of many actinides is quantified using a modified version of Serpent 2