Management of Commercially Generated Radioactive Waste - U.S. ...

4.38
4.3.3.4 Immobilization of Wet Wastes and Particulate Solids
Prior to shipping and isolating wet wastes, they must be immobilized. This step may
be done by a variety of methods. Immobilization of these wet wastes in bitumen and cement
(bituminization and cementation) is discussed here as applied to an FRP and a MOX-FFP.
Another alternative, urea-formaldehyde immobilization, requires process equipment similar
to that for cementation. Cementation is the example treatment process chosen for this
Statement.
Cementation (Example Method)
Immobilization of radioactive wet wastes in cement involves mixing the wastes with
cement, placing the mixture into drums, and allowing the mixture to harden to a liquid-free
product. Cement immobilizaion of radioactive wastes has been widely used in the U.S. A
variety of cementation technologies have been developed, including in-drum mixers, drum tum-
blers, and in-line mixers, each of which is described in ERDA-76-43. For this Statement, a
drum-tumbling system was selected for the following reasons:
* Both liquid and dry wastes can be immobilized without altering the commercially
available technology.
* The wastes are mixed inside the drums, preventing external solidification of the
waste-cement mixture.
The process flow diagram for a cementation system at an FRP is shown in Figure 4.3.10.
A similar system can be used at a MOX-FFP after neutralization of the acidic liquids and
treatment to remove the ammonia present in those wastes (to avoid possible later pressuriza-
tion of sealed containers).
DRUMS
I1W LIOUIO AND SLURRY WASTE PNEUMATIC
STORAE
CONVEYOR
TANKS VEN COVEYOR
RECYCE SLURRY WATER
VENT TO ATMOSPHERE
BAG METEING
FILTER PUMP
OPTIONAL INCINERATOR ASH FEE SYSrTM
M IXDANO E PA CHARCOAL
DECAcNT F L FILTR - TO FRP-APS
STANA f Ce t a
FUSH R WATER
CEMETWALL.
STC E I IFILLEO DRUAMS TO STORAGCE
SOLID
WASTE
MIXING ADDITION DRUM FILLING SCALE
IEIGHTS AND CAPPING INSPECTION
AND WEIGHING
FIGURE 4.3.10. Process Flow Diagram for Cementation at Fuel Reprocessing Plant
Lo w