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

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quirements, high costs, and probably increased environmental impacts (see Section 6.1.8.4).
Thus, some form of waste separation would be required. For HLW, the option appears to be
feasible, on the basis of the much lower number of Space Shuttle flights that would be
required (approximately one launch per week to dispose of HLW from 5000 MT of heavy metal
resulting from operations of approximately 170 GWe nuclear capacity). It is also possi-
ble that the space option would be used to rid the Earth of smaller quantities of radio-
active wastes that pose special hazards for long-term terrestrial disposal. The disposal
of selected isotopes would require chemical partitioning, with its high costs and secondary
waste streams. Remotely handled and contact-handled TRU wastes from the recycle options
would require geologic disposal.
Waste-System Description
The concept for space disposal of nuclear waste described here is the current DOE/NASA
reference concept as relfected by the preferred options in Figure 6.1.22. To place the
space disposal concept into perspective from a total system viewpoint, Figure 6.1.23 shows
the waste management system, emphasizing the location and process flow details of the space
disposal alternative within the total system. Two points are apparent from this figure:
(1) chemical processing would definitely be required for space disposal of waste, and (2)
the mined geologic repository would be part of the total system. The following discussion
briefly summarizes the mission profile frm the standpoint of waste-type compatability,
prelaunch activities, and orbital operations. Battelle (1980) presented a more detailed
discussion of this profile and various element definitions and requirements.
Prelaunch Activities. The prelaunch activities would include nuclear waste processing
and payload fabrication, ground transportation of waste, on-site payload preparation, and
final staging operations.
Typically, spent fuel rods from domestic power plants would be transported to the waste
processing and payload fabrication site in conventional shipping casks (see Chapter 4). A
high-level waste stream containing fission products and actinides, including several tenths
of a percent of the original plutonium and uranium, would result from the uranium and pluto-
nium recovery process. This waste would be formed into a "cermet" matrix (Aaron et al.
1979) (an abbreviation for ceramic particles uniformly dispersed within a metallic phase),
which has been shown to have superior properties compared with other potential waste forms
for space disposal (Battelle 1980). The waste would then be fabricated into an unshielded
5000-kg sphere. Within a remote shielded cell, this waste payload would be loaded into a
container, which would be closed be sealed, inspected, decontaminated, and packaged into a
flight-weight gamma radiation shield assembly. During these operations and subsequent
interim storage at the processing site, the waste package would be cooled by an auxiliary
cooling system.