PLENTIFUL ENERGY

CHAPTER 9
THE BASIS OF THE
ELECTROREFINING PROCESS
In this chapter our aim is to provide a physical understanding of the
electrochemical basis of electrorefining—the heart of IFR pyroprocessing. We are
indebted to John Ackerman, Argonne‟s fine electrochemist, for his generous advice
and help and in the editing of this chapter. Our goal also is to give as simple and
straightforward a presentation as we can manage. In seeking simplicity there may
be some error in detail, but the major themes of this chapter are as they are
understood at the present time. Responsibility for the former lies with the authors;
for assurance of the latter we are in debt to Dr. Ackerman.
The chapter is an abbreviated treatment of the material given in Appendix A.
The appendix treats the electrochemistry of the process in detail from the
fundamental particles on up—through the concepts used, the thermodynamics, a
little of the kinetics of reactions, and the details of the calculations of the important
properties and products. Those who wish a fuller understanding of the subject are
referred to Appendix A.
9.1 Electrorefining Spent Fuel
The inexpensive compactness of the IFR fuel cycle, the effectiveness of the
separations of product from waste, and in fact the very ability to recycle spent fuel
at all, depend on one piece of equipment: the IFR electrorefiner. Its operation is
based on the principles of electrochemistry, a science at the intersection of
electricity and chemistry. One specific class of chemical reactions gives rise to the
electrical phenomena that are the basis for all of electrochemistry. When an
electrode (a conductor of electrons) is immersed in an electrolyte (which contains
electrically charged ions and can conduct electricity) it forms an ―electrochemical
cell.‖ Chemical reactions then occur naturally at the interface between electrode and
electrolyte which convert chemical energy to electrical energy spontaneously and
naturally, as a battery does. However, if the object of a process is to have a
particular chemical reaction occur, the reverse can be done: a voltage can be
imposed that alters the electrical phenomena so as to cause the desired chemical
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