[1K12-14] Nuclear Transmutation

[1K13] Design study on fast reactor core and LLFP assembly for nuclear transmutation

(1) Characteristics of nuclear transmutation in SFRs

*Yoshihisa Tahara¹, Peng Hong Liem^1,3, Naoyuki Takaki¹, Satoshi Chiba² (1. TCU, 2. Tokyo Tech., 3. NAIS)

Keywords:Nuclear Transmutation, Fast reactor, Long-lived fission products, LLFP assembly

The characteristics of nuclear transmutation of ¹²⁹I in a fast reactor were studied. The nuclear parameters, e.g. transmutation rate, core reactivity, conversion ratio and power peaking factor, were analyzed by a Monte Carlo code for a fast reactor in which LLFP targets of BaI₂ with moderator YH₂ (and/or YD₂) were loaded in its blanket region. As a result, it has been found that the transmutation rate (%/y) increases with increasing YH₂ volume ratio and the value of transmutation (g/y) becomes maximum at 30 %. However, remarkably high peak powers appear in the fuel region adjacent to the LLFP assembly. Thus, some measures must be devised to suppress such high power for maintaining safety margin of the reactor.