Core Design of a 1200 MWe Sodium Cooled Fast Reactor by Using Non-Fuel Rods

Korea Atomic Energy Research Institute (KAERI) has developed a 600MWe sodium cooled fast reactor, the KALIMER-600 reactor core concept using a single enrichment fuel without blanket assemblies. Single enrichment fuel concept was achieved by using the special fuel assembly designs where non-fuel rods (i.e., ZrH1.8, B4C, and dummy rods) were used. Also, a power flattening is achieved by using the core region wise cladding thickness without non-fuel rods. The design concept of KALIMER-600 was chosen as a reference design of a Gen IV Sodium cooled Fast Reactor (SFR). As an on-going study of a Gen IV SFR development to enhance the economics and safety characteristics, the 1200 MWe design concept is being developed by KAERI. In this paper, a new core design concepts for a 1200 MWe SFR with single enrichment fuels by using nonfuel rods such as vacancy rods, steel rods and graphite rods are described. All the neutronic calculations are done with the KCORE system. The depletion analysis is done with the equilibrium model of the REBUS-3 code system where the DIF3D module solves the neutron diffusion equation with the HEX-Z nodal method and a 25-group cross section set to obtain the neutron flux and power distributions. The cross section set is prepared based on the ENDF/B-VI library