Project Salt Vault:Radioactive Waste
Disposal in a Salt Mine
W. J. BOEGLY, Staff Member
R. L. BRADSHAW, Staff Member
F. M. EMPSON, Staff Member
W. C. McCLAIN, Staff Member
F. L. PARKER, Staff Member
Health Physics Division
W. F. SCHAFFER, JR., Staff Member
Chemical Technology Division
Oak Ridge National Laboratory
Oak Ridge, Tennessee
INTRODUCTION
Chemical reprocessing of power reactor fuel produces a chemically complex
and hazardous effluent which cannot be handled by conventional waste-disposal
methods. Special methods of disposal are required safely to contain these radioactive wastes for centuries, with adequate safeguards to prevent the escape of the
fission products to the environment. At the present time, the most promising
method for the disposal of high-level, heat-generating, power reactor wastes is
the conversion of liquid wastes to solids, followed by the ultimate disposal of the
solids in salt formations.
In September 1955, at the request of the Atomic Energy Commission, a
meeting of geologists and engineers was organized by the Earth Sciences Division
of the National Academy of Sciences -- National Research Council to discuss the
possibility of permanently disposing of radioactive wastes in geologic formations.
In the committee report, salt was recommended as the most practical immediate
solution because of its impermeability, geographic distribution, thermal conduc-
tcause of its impermeability, geographi
ngth, and abundance (1).
.
tivity, stre
As a result of these recommendations, studies on the disposal of high-level
liquid and solid wastes were initiated at ORNL. Basic problem areas studied were
the heat transfer from the waste to the salt, the effects of heat and radiation on
rock salt,   and the economics of an actual disposal facility in a salt mine (2,4).
PROJECT SALT VAULT
Based on the studies summarized above, it was decided that a field experiment should be designed and operated to demonstrate that it is feasible and
safe to dispose of radioactive solid wastes in a salt mine. This demonstration,
called project Salt Vault, has also been designed to illustrate the equipment and
operations necessary for an actual disposal facility. Since packaged solids are not
currently in production, and pilot plant quantities will not be available for some
time, it has been decided to operate Project Salt Vault using irradiated fuel assemblies as the heat and radiation sources. A study of available fuel assemblies
has shown that it is possible to simulate solidified wastes using 90-day-cooled
Engineering Test Reactor (ETR) fuel assemblies (2). The other main difference
between Project Salt Vault and an actual disposal operation is that the fuel as-
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