Pyrochemical processing of spent nuclear fuels makes use of chemical and electrochemical reactions in molten salts and liquid Cd. Design and optimization of the pyrochemical processing requires not only thermodynamic but also kinetic properties of actinides and fission products. In this study, an electrochemical method was applied to measure the diffusion coefficient of Pu in liquid Cd; 6.8 x 10(-6), 9.3 x 10(-6) and 1.0 x 10(-5) cm(2) sec(-1) at 723, 773 and 823 K, respectively. The activation energy was evaluated to be 19 kJ mol(-1) from the temperature dependence of the diffusion coefficient. (C) 2014 The Electrochemical Society. All rights reserved.