Study of a new compact fast reactor core design

A study was conducted to investigate conceptual Liquid Metal Reactor (LMR) designs, employing some unconventional design features, for improved economics and safety. The unconventional design elements were used to supplement the conventional design measures, which alone did not lead to a truly competitive LMR design. Better economics was obtained through simplicity and compactness of core design. For simplicity of core design, internal blankets were omitted. Core compactness was achieved by maximum power flattening. This was done by employing axial and radial enrichment zones along with axial and radial (BeO) reflectors. To further enhance core compactness, the in-core control rods were replaced by reflector controls. For improved safety, the objective was to reduce both coolant void and burnup reactivities. However, even with the use of a wide spectrum of unconventional design features, such as burnable poisons, peripheral reflectors and inner moderating regions, it was not possible to overcome the classical known fact that both coolant void and burnup reactivities cannot be reduced simultaneously. The only resolution of this dilemma appeared to be to minimize coolant void reactivity, and to manage the burnup reactivity losses, such that an accidental insertion of significant amounts of reactivity is mechanically not possible. A conceptual design with these characteristics is described in this thesis