An optimization study of Kalimer core thermal hydraulic design with the improvement of its design tools

KALIMER (Korea Advanced Liquid Metal Reactor) is currently in a design optimization study at KAERI, after completion of the conceptual design study early this year. It is a pool-type sodium cooled prototype reactor with a thermal output of 392,0 MW (electric power of 150,0 MW). In phase I of the study, the KALIMER core was initially designed with 20% enriched U-10%Zr binary alloy metallic fuels, which generates a net negative reactivity with inherent safety characteristics. But in phase II of the study, it was changed, to increase the breeding characteristics, to a heterogeneous core fueled with U-Pu-Zr ternary alloy fuel. The ultimate objective of the KALIMER program is to develop an inherently and ultimately safe, environmentally friendly, proliferation-resistant and economically viable fast reactor concept. The subchannel analysis codes are effective tools to calculate temperature distributions in core and subassemblies. Two codes are used at KAERI to compute the core-wide temperature profiles in KALIMER cores, i.e, SLTHEN and MATRA-LMR codes. These codes will provide temperature maps for all pins in all assemblies and thus facilitate core-wide failure probability studies. It is expected they will be extensively used during preliminary and final design phases. This paper summarizes the optimization study of KALIMER core thermal hydraulic design and analysis with the improvement of its design tools. (author)