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

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* The use of commercial power reactors as transmutation devices might result in fissile
penalties, reactor peaking problems, reduced reactor availability, and increased
operating costs.
* Because of increased concentrations of radioisotopes with high specific activities,
and/or modifications of existing systems due to changes in requirements, transmutation
recycles could require additional containment systems to limit the release of radioactivity
at the reactor site to acceptable levels.
* Many transmutation cycles would increase fuel handling requirements because of the more
frequent insertion and removal of fuel and transmutation targets from the reactor core.
Most transmutation cycles would result in increased shielding requirements both for
fresh and spent fuels and transmutation targets.
* Decommissioning and disposal of reagents from partitioning and transmutation facilities
would be complicated by the increased demands for shielding, multiple chemical processes,
and waste streams.
The duration of the transmutation cycle is important in estimating its overall effec-
tiveness in reducing the total radiotoxicity of transmutable elements in the environment.
Premature termination of the transmutation cycle could actually increase the radiotoxicity of
the wastes. This is because the resulting inventory sent to a final disposal system might
have more activity than it would if the transmutation cycle had not been initiated.
R&D Requirements
The R&D requirements for partitioning would involve specific near-term subtasks to clar-
ify points of uncertainty in the current process parameters and techniques. However, to
fully develop and demonstrate actinide partitioning, a program would have to include addi-
tional process research and development, a cold (nonradioactive) testing facility, equipment
development and testing, and pilot plant design, licensing, construction, testing, and
operation.
Transmutation R&D would include specific nuclide cross section measurements, reactor
physics calculations, and irradiation to full burnup of test fuel assemblies to verify
calculations. The irradiation tests would also serve to confirm the design and fabrication
of the fuel assemblies and their compatibility with and performance in the reactor during
power operation.
The design, construction, and testing of a prototype shipping cask made from the rela-
tively unconventional materials proposed might also be required. Specific aspects of cask
technology that might require attention are: techniques for industrial fabrication of spe-
cial shielding materials, such as B 4 C/Cu and LiH, investigation of the ability of the cask
using such materials to conduct the heat from the fuel contents, and the effect of the un-
usual construction materials on safety considerations in cask design.
Finally, continuing overall studies to define the preferred methods of operating the fuel
cycle and the impacts and benefits of this operation would be of primary importance.