ORNL-5388 - the Molten Salt Energy Technologies Web Site

5-22
In the case of metal-clad oxide fuels that are thorium based, the areas requiring
further study are essentially the same as those listed above for the Pu/U oxide fuels; how-
ever, in contrast to Pu/U-oxide fuels, where significant effort has already been devoted
toward resolving this list 0; areas, relatively little R&D has been performed to date for
thorium-based fuels and consequently a larger amount of research and development would be
required.
The intense radioactivity of the decay daughters of 232U (which is produced in the
thorium along with the 233U) requires that the refabrication processes all be remotely
operated and maintained. This requirement will necessitate additional development of the
refabrication processes and may require the development of new fabrication methods.
qualification of U/Th and Pu/Th oxide fuels will also require additional R&D efforts.
fuel element.
HTGR fuels are coated uranium oxide or carbide microspheres embedded in a graphite
have been identified; however, additional R&D prior to construction of a hot demonstra-
tion facility is needed.
The process and equipment concepts for refabricating HTGR fuel remotely
This should cover:
(1) the scaleup of refabrication equipment,
(2)
(3)
(4)
the recycle of scrap material,
the control of effluents, and
the assay of fuel-containing materials.
Additional R&D will also be required for qualification of the recycle fuel.
While the reference HTGR fuel cycle already includes thorium, further development work
will be required to fabricate DUTH fuels for HTGRs because of the requirement of a higher
uranium content of the fiss
irradiation.
Fuel Reprocessing
le part
The
cle and the increased production of plutonium during
The basic technology for reprocessing of uranium and uranium/plutonium oxide pellet
fuels with low burnup exists in the Purex process.
of government reprocessing experience with military-related fuels;
This technology is based on many years
reprocessing plant for mixed oxide power reactor fuels that conforms to current U.S. federal
and state requirements has not yet been operated.
pilot-scale work has been successfully carried out on ‘all important processes and components
of the reprocessing plant, operability, reliability, and costs of an integrated plant have
not been demonstrated in all cases at fuel exposures expected in commercial reactors.
Specific areas that still require development work include the following:
however, a commercial
Additionally, while engineering or
(1 ) operation and maintenance of the mechanical headend equipment;
(2) ‘methods for handling highly radioactive residues that remain after the dissolution
(3)
of high-burnup fuel;
the technology for reducing radioactive off-gas releases (e.g., Kr-85, iodine and
tritium) to conform to anticipated regulations;