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Separation of platinum-group metals (PGMs: Ru, Rh, Pd) and Mo from high-level liquid waste (HLLW) makes the vitrification process more stable. Aluminum ferrocyanide (AlHCF) has been synthesized, and it is suitable for the simultaneous recovery of PGMs and Mo from HLLW. In this study, an adsorption experiment onto AlHCF was conducted in a spent fuel solution prepared from an irradiated MOX fuel. An adsorption experiment in a simulated HLLW with 26 elements was also conducted as reference. As a result, both Pd and Mo have been successfully adsorbed on AlHCF in both the spent fuel solution and the simulated HLLW. Americium was not adsorbed onto AlHCF as tri-valent lanthanide ions were.

The release behavior of Pu and Am was investigated under the reducing atmosphere expected in sodium cooled fast reactor severe accidents. Irradiated Pu and U mixed oxide fuels were heated at maximum temperatures of 2773 K and 3273 K. EPMA, γ-ray spectrometry and α-ray spectrometry for released and residual materials revealed that Pu and Am can be released more easily than U under the reducing atmosphere. The respective release rate coefficients for Pu and Am were obtained as 3.11 × 10 −4 min −1 and 1.60 × 10 −4 min −1 at 2773 K under the reducing atmosphere with oxygen partial pressure less than 0.02 Pa. Results of thermochemical calculations indicated that the main released chemical forms would likely be PuO for Pu and Am for Am under quite low oxygen partial pressure.