PLENTIFUL ENERGY

The first operation is done in the pin chopper. Intact fuel pins are prepared for
electrorefining by chopping them into short segments, exposing the fuel, and
removing scrap such as the spacer wire, end caps, and plenum. The highly
radioactive fuel is then introduced into the electrorefiner in perforated steel baskets.
Shown in Figure 8-5, the electrorefiner consists of the process vessel with
associated heater/insulator assembly, cover, and support stand; electrode assemblies
(anodes and cathodes) and their associated handling and placement mechanisms;
ancillary systems for cover gas circulation, stirring, materials addition, sampling,
and measurements; and an instrumentation and control system. A staging or support
station services the electrorefiner. It attaches and removes anode and cathode parts,
removes product from the cathodes, and empties the cladding hulls from the anode
baskets. The design is based on the engineering-scale electrorefiner in service in the
Chemical Technology Division at the Illinois site since 1987 and still ongoing.
Figure 8-5. Schematic of electrorefiner
The electrorefiner operates at a temperature of 500 o C. It has a layer of molten
cadmium, ten centimeters thick under thirty-six centimeters of molten salt. It is
heated by the thermal radiation from a furnace assembly of resistance heaters in
low-density ceramic insulator blocks. Circular ports in the steel cover and thermal
radiation baffles provide access for four electrodes, 28 cm in diameter, and a stirrer
20 cm in diameter. Other smaller ports allow material additions, sampling
measurement, and cover gas control. The electrode assemblies have a long shaft
with an adapter for an anode or a cathode bottom fixture, a rotation motor, rotating
electrical contacts, a port cover, a containment housing, and various instrumentation
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