During the electrorefining test of uranium or rare earth metal in the the molten salts e.g. LiCl-KCl and LiF-CaF2, dissolution of metal in the anode and reduction in the cathode occurr simultaneously, the reduction potential can be monitored and controlled by the reference, e.g. AgCl/Ag or Pt QRE, but how to monitor and control the dissolution potential of the metal in the anode ?