Effect of decontamination factor of recycled actinide and FP on the characteristics of SCNES

Effect of the decontamination factor (DF) of nuclides to be confined in the closed fuel cycle was examined in terms of the system characteristics. Two kinds of indices, equilibrium mass and equivalent radiotoxicity, were used to determine the recovery perfectivity of the nuclides. By using the equilibrium mass, extremely high DF had to be attained. The required values of DF were 10⁸ for LLFP and 10¹² for actinides. On the other hand, using the radiotoxicity, inferior perfectivity of recovery, DF=10⁶, could be acceptable for actinides and there is no necessity of LLFP recycling for transmutation because they only have comparable radiotoxicity with the supplied uranium to the system. The required DF which provide ignorable loss of waste to the outside of the system depends on what index we use. Generalization of index to quantify the hazard or nuisance of nuclear waste and setting the criteria remains unsettled questions.