Core design for super fast reactor with all upward flow core cooling

Abstract

A 1000MWe level supercritical-pressure light water-cooled fast reactor (Super FR) is proposed in this paper. The newly improved features include two flow paths which both applies upward flow pattern. Compact lattice of MOX fuel pins are arranged in hexagonal seed assembly while blanket assembly comprised of depleted UO2 fuel pins wrapped with solid moderator ZrH layer for negative void reactivity. This core design includes 162 seed assemblies and 73 blanket assemblies with 1.7cm of solid moderation layer of ZrH, the core active height is 3.6m. The axial coolant density distribution of the core is far from uniform due to the all upward flow pattern, however, by applying axial Pu enrichment zoning and new loading and refueling scheme, flattened power distribution is obtained and all the design criteria as well as limitations have been fulfilled with significant delivery of high power density up to 237kw/L, 500°C average core outlet temperature, both whole core and local negative void reactivity.