Conceptual designing of reduced-moderation water reactor with heavy water coolant

The conceptual designing of reduced-moderation water reactors, i.e. advance d water-cooled reactors using plutonium mixed-oxide fuel with high conversi on ratios more than 1.0 and negative void reactivity coefficients, has been carried out. The core is designed on the concept of a pressurized water re actor with a heavy water coolant and a triangular tight lattice fuel pin ar rangement. The seed fuel assembly has an internal blanket region inside the seed fuel region as well as upper and lower blanket regions (i.e. an axial heterogeneous core). The radial blanket fuel assemblies are introduced in a checkerboard pattern among the seed fuel assemblies (i.e. a radial hetero geneous core). The radial blanket region is shorter than the seed fuel regi on. This study shows that the heavy water moderated core can achieve negati ve void reactivity coefficients and conversion ratios of 1.06-1.11. (C) 200 1 Elsevier Science B.V. All rights reserved.