Neutronic Space-Time Effects with Thermal-Hydraulic Feedback in Large Homogeneous and Heterogeneous Liquid-Metal Fast Breeder Reactors

Two-dimensional multigroup space-time kinetics calculations with thermal-hydraulic feedback were performed for 1000- and 1800-MW(electric) homogeneous and heterogeneous liquid-metal fast breeder reactors. The recent development of the FX2-TH code has made feasible an evaluation of the importance of spatial effects in the calculation of operational fast reactor transients. This paper concerns two basic questions. The first is the relative capability of point kinetics and space-time kinetics calculations in predicting reactor parameters under an initiating transient due to the asymmetric withdrawal of a single control rod. The second question concerns the neutronic transient behavior with thermal-hydraulic feedback of homogeneous and heterogeneous LMFBR cores. 6 refs.