THERMODYNAMIC QUANTITIES OF ACTINIDES AND RARE-EARTH ELEMENTS IN LIQUID BISMUTH AND CADMIUM

The activity coefficients of uranium, lanthanum, cerium, praseodymium, gadolinium and yttrium in liquid bismuth were measured electrochemica lly as 10(-4.65), 10(-13.44), 10(-13.00), 10(-12.81), 10(-11.04), and 10(-10.17) respectively at 773K. The activity coefficients of neodymiu m and neptunium were estimated as 10(-12.85) and 10(-7.43) respectivel y from the standard potentials in LiCl-KCl eutectic molten salt and th e distribution coefficients in the LiCl-KCl/bismuth system. The partia l molar enthalpy of mixing and the partial molar excess entropy of sol utes in both liquid bismuth and cadmium were evaluated from the change in the activity coefficients with temperature.