Degradation of nuclear fuel debris analog by siderophore-releasing microorganisms

Onuki, Toshihiko*; Nakase, Masahiko*; Liu, J. ; Dotsuta, Yuma; Satou, Yukihiko   ; Kitagaki, Toru  ; Kozai, Naofumi   

We investigated the effect of siderophore-releasing microorganism (SB) on fuel debris. Fuel debris analogue pellet samples (FDAPSs) and powder samples containing CeO (an alternative to UO)-ZrO solid solution, and metallic iron were fabricated. FDAPSs were contacted with SB on a membrane filter placed on agar medium for 50 days. By the addition of SB, Fe-containing degradation products were detected on the filter, and on the agar medium, revealing that some fraction of Fe ions were dissolved and precipitated on FDAPSs, and the rest became detached from FDAPSs, and migrated through the filter. Although Zr were detected in small amounts on the Fe area, the dissolution of Zr may be limited. These results clarify that the presence of RB accelerates the degradation of fuel debris in which Fe metal regions are preferentially degraded, and some fraction of Fe were detached and migrated from the fuel debris.