Disposal of Radioactive Wastes in Bedded
Salt Deposits
WILLIAM C. McCLAIN, Assistant Director
Salt Project
Health Physics Division
Oak Ridge National Laboratory
Oak Ridge, Tennessee
INTRODUCTION
During the very early stages of the nuclear power reactor development
program, it was recognized that, unless the problem of disposing of the large
quantities of highly radioactive fission products resulting from the chemical
reprocessing of spent fuel was solved, the use of nuclear power as a source of energy
would be seriously impeded. The disposal of these wastes is, indeed, a formidable
problem; they require heavy shielding during any handling operations and complete
and total isolation from the biological environment for periods up to several
hundreds of thousands of years. The longevity of the hazard associated with these
materials implies that any true "disposal" system must reliably achieve the required
isolation without reliance on surveillance, monitoring, and control by man.
In September 1955, a National Academy of Sciences-National Research
Council committee of geologists and geophysicists, which was established to consider
the possibility of disposal of radioactive wastes in geologic structures within the
continental United States, concluded that natural salt formations at sufficient depth
were the most promising potential disposal sites (1).
Salt and salt deposits have several advantageous properties which contributed
to this conclusion, including:
1. Salt deposits are essentially impermeable and are completely isolated from
circulating groundwater. Furthermore, any fractures, which should develop, tend to
heal due to the plastic properties of salt. This means that materials deposited in salt
formations are unlikely to come into contact with leaching solutions over very
extended periods of time.
2. Salt is widely distributed and abundant. In the continental United States,
approximately 500,000 square miles in portions of 23 states are underlain by salt and
its utilization for this purpose will not sterilize a valuable natural resource.
3. Salt formations are, in general, located in regions of low seismicity, thereby
reducing the chances of breaching the containment.
4. Excavation in salt is a well-developed technology and low-cost operation.
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