FY2010 - Oak Ridge National Laboratory

Director’s R&D Fund—
Advanced Energy Systems
ADVANCED ENERGY SYSTEMS
05214
Development of Cermet High-Level-Waste Forms
Robert Jubin, Scott Aaron, Emory Collins, David W. DePaoli, Guillermo D. DelCul, Kevin Felker,
Douglas Kothe, Bradley D. Patton, Raymond Vedder, Stewart Voit, and Robert Wham
Project Description
The successful reexpansion of nuclear energy is dependent on the development of waste disposal options
that minimize use of repository space and maximize efficiency and public safety. Toward this goal, we
are developing concepts for advanced cermet waste forms to optimize storage of high-level wastes that
will be generated in next-generation nuclear fuel cycles. Cermets, which consist of ceramic phases
dispersed in continuous metal matrices, provide a unique opportunity to tailor waste forms that take
optimal advantage of the properties of both metallic and oxide materials. In this project, we are exploring
the development of cermets consisting of ceramic materials that sequester the short-lived, but highly heatgenerating,
137 Cs/Ba and 90 Sr/Y components of spent fuel, along with metal alloys that enable isolation of
long-lived fission products such as 99 Tc, noble metal components, transition metals, fuel assembly
hardware, and cladding materials. The proposed waste form will provide significant cost benefit by
improving the heat-handling capability of the waste, thus increasing net repository capacity. We are also
investigating the benefits of combining these two waste types and processes to produce an optimum waste
form with minimized processing costs. The “proof of concept” is being established through
experimentation and preliminary modeling studies to elucidate the long-term performance of such a
cermet waste form. Success in this work will create an important new option for investigation in programs
of the DOE Office of Nuclear Energy.
Mission Relevance
The United States has experienced a resurgence of interest in the possibility of reprocessing spent fuel to
recover valuable materials and to reduce the load on waste repositories. In the traditional glass high-level
waste (HLW), most of the residual activity and decay heat generation that occurs in the first
100-300 years arises from the ~30 year half-life 137 Cs/Ba and 90 Sr/Y components. Waste loading in the
remaining HLW can be increased if these components are separated. The project provides a new option
for HLW that affords the benefits of simplified separations technologies and improved waste forms,
which, in turn, enable overall cost minimization. The proposed cermet waste form will improve the heat
transfer characteristics and reduce the centerline temperature of the waste monolith, thus allowing for
increased waste loading compared with that for a glass. Success in this work will create an important new
option for investigation in programs of the DOE Offices of Nuclear Energy and Environmental
Management. The new cermets also have application for advanced radioisotope source forms of interest
to both the Nuclear Regulatory Commission and the Department of Homeland Security.
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