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

4.39
The packaged waste output of the cementation systems depends markedly on whether or not
the combustible wastes are incinerated (because the incinerator ash and scrubber solutions
are additional feeds to the cementation systems). If the combustible wastes are inciner-
ated, the output of the cementation systems will be 106 55-gallon drums/GWe-yr at an FRP and
31 55-gallon drums/GWe-yr at a MOX-FFP. About 40% of the drums originating at an FRP and
all of the drums originating at a MOX-FFP could be contact-handled.
If the combustible wastes are not incinerated, the packaged waste output of the cemen-
tation systems will be 49 55-gallon drums/GWe-yr at an FRP and 11 55-gallon drums/GWe-yr at
a MOX-FFP. All of the drums originating at an FRP require remote handling, but those origi-
nating at a MOX-FFP would be contact-handled.
Bitumenization
Imnobilization of radioactive wet wastes in bitumen involves mixing the waste with
liquid bitumen or asphalt binder and placing it in 55-gallon drums. The temperature of the
binder at the time of mixing (above 100 0 C) evaporates the free water, and thus reduces the
waste volume. Use of bitumen to immobilize radioactive wastes has been well demonstrated,
largely through extensive operating experience in Europe. However, it is uncertain whether
bitumenized waste forms will meet waste form criteria for repositories.
Several types of bitumenization processes have been developed as discussed in
ERDA-76-43. In this Statement, a continuous screw extruder process was considered for the
following reasons:
* The screw extruder bitumenization process operates at lower temperatures and with
shorter residence times than the batch process, thus minimizing off-gas problems.
* The process uses well-demonstrated technology.
* The process is commercially available in the U.S.
A process flow diagram for a bitumenization system at an FRP is shown in Figure 4.3.11.
A similar system can be used at a MOX-FFP after neutralization of acidic liquids.
If the combustible wastes are incinerated, the packaged waste output of the bitumeniza-
tion systems will be 48 55-gallon drums/GWe-yr at an FRP and 10 55-gallon drums/GWe-yr at a
MOX-FFP. About 2% of the drums originating at an FRP and all of the drums originating at a
MOX-FFP could be contact-handled.
If the combustible wastes are not incinerated, the packaged waste output of the bitu-
menization systems will be 26 55-gallon drums/GWe-yr at an FRP and 8.7 55-gallon drums/
GWe-yr at a MOX-FFP. About 3% of the drums originating at an FRP and all of those originat-
ing at a MOX-FFP could be contact-handled.
4.3.4 Gaseous and Airborne Waste Treatment
Spent nuclear fuel contains some radionuclides that are released in gaseous form during
certain treatment operations. Such volatile radionuclides include the fission products
H, 85 Kr, and 129I and the activation product 1C. A small portion of the fission product