Design basis of the fission product assembly in the subcritical transmutation system HYPER

An accelerator-driven subcritical system, named HYPER (HYbrid Power Extraction Reactor), is under development in KAERI (Korea Atomic Energy Research Institute). Although HYPER is mainly to incinerate the transuranium radioactive nuclides, long-lived FPs (Fission Products) can also be loaded for transmutation. This paper is concerned with conceptual design of the FP assemblies for Tc-99 and I-129. To enhance the transmutation rate of the FPs, a moderator-containing FP assembly is introduced and CaH2 is chosen as the moderator. The CaH2 moderator is placed in the central region of the FP assembly so that detrimental effects of the moderator can be minimized