Alpha-radiolysis of organic extractants for separation of actinides

Sugo, Yumi; Taguchi, Mitsumasa; Nagaishi, Ryuji ; Sasaki, Yuji  ; Hirota, Koichi; Morita, Yasuji  

The radiolytic stabilities of the organic extractants for the separation of actinides have been commonly evaluated by the irradiation with -rays as the most convenient method. However in the actual partitioning process of HLW, the extractants will be exposed to alpha-particles emitted from actinides, as well as beta- and -rays from various fission products. In this study, alpha-radiolysis of -tetraoctyldiglycolamide (TODGA) in -dodecane was investigated by the irradiation with helium ion beam accelerated by a tandem accelerator using the TC1 irradiation apparatus in the TIARA facility. The sample was also irradiated with Co -rays for comparison of the radiation chemical yields between - and -rays. It was found that TODGA had almost fourfold resistance to -rays, as compared with -rays. This result suggests that the radiolytic degradation of TODGA has been hitherto overestimated only by the irradiation with -rays.