PLENTIFUL ENERGY

eaction. Current flows, electrical energy is converted to chemical energy, and
chemical bonds are formed or broken as needed to form the products desired. This
is what happens in electroplating, for example—and this is what happens in the IFR
process.
The IFR process electrolyte is a molten mixture of lithium chloride and
potassium chloride salts. Chopped-up fuel pieces are made the anode of the
electrochemical cell; a metallic cathode will collect the product. Voltage is applied
and the spent fuel gradually dissolves into the electrolyte. Here the first and very
important separation takes place. The most chemically active (the most driven to
react) of the fission products, which are also responsible for much of the
radioactivity, react immediately with the ionic compound uranium chloride, UCl 3 ,
in the electrolyte. It is present as a seed from initial operation and maintained by
electrorefining operations. The active fission products displace the uranium and
form their own chlorides. At actinide-refining voltages, the chlorides of the active
fission products, once formed, are very stable, and they remain in the salt until they
are removed as waste in a later operation. The positively charged uranium and
higher actinide ions diffuse through the electrolyte toward the cathode, and only
they deposit in quantity on the cathode because the higher stability of both the
chlorides of the electrolyte materials and the chlorides of the dissolved active metal
chlorides prevents them from also ―reducing‖ to metals and depositing on the
cathode at the voltages used.
9.2 Energy Transfer: The Thermodynamics of the Process
The fundamental bases of the process are actions at the molecular level of atoms,
ions, and electrons. Chemical reactions are just these very small particles
interacting with each other. Tiny energy changes occur in these interactions, and
these energy changes determine what happens in the process. Classical
thermodynamics, which deals precisely with energy relationships (e.g. energy
cannot be created or destroyed), gives us the means to predict what chemical
reactions are possible. Only if the energy content of the products of the reaction is
less than the sum of the energy contents of the reactants going into it is a chemical
reaction possible. The fraction of the energy that isn‘t dissipated in the reaction and
is available to drive the reaction is called the free energy.
The free energy is the maximum energy available from a reaction for conversion
to other forms of energy. It is a potential energy, energy stored and actually
available to ―flow downhill‖ and do useful work. The magnitude of the free energy
in the reactions of various elements forming their chloride ionic compounds is
available in tabulations in the literature and for the most relevant elements is given
in Table 9-1 below. [1] Our process is based on the differences in free energies of
chloride formation of the various elements and compounds in the electrorefiner.
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