Liquid metals and salts can be employed as working media in pyrochemical reprocessing of spent nuclear fuels (SNF). Information on activity coefficients and solubility of SNF components is required to estimate the possibility and efficiency of elements separation in a fused salt � liquid metal system.In the present study uranium activity, activity coefficients and solubility were determined in gallium, indium and gallium-indium alloys (containing 21, 40 and 70 wt.% In). Uranium activity was determined between 573-1073 K from the results of emf measurements. Uranium activity in Ga-In alloys is close to that in pure gallium and below 600 K there is very little difference between Ga and Ga-In based systems, Fig. XRD analysis showed that in cooled to room temperature U-Ga-In alloys only UGa3 intermetallic compound (IMC) was present. Although UGa3 and UIn3 are isostructural, even in the 70 wt.% indium containing systems the cell parameter of the IMC, 4.255�0.002 �, is very close to that of pure UGa3, 4.251�0.002 �, confirming that no mixed U(Ga,In)3 phases is formed. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/240nm/uploads/40239_cover1b.jpg' alt='' /> Solubility of uranium was determined employing several techniques, alloy filtration, centrifuging and precipitation. The data were obtained from 1073 to 433 K for In, 423 K for Ga-In (40 and 70 wt.% In) and room temperature for Ga and Ga-21 wt.% In alloys. Activity coefficients of uranium were calculated at 1073-573 K from the difference of found activity and solubility values.

Activity and solubility of uranium in gallium, indium and gallium-indium based alloys

247th National Meeting (2014)

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