Dec. 10, 1997 ROLLA, MO. -- Glass may be the answer to safely dispose of nuclear waste, says a University of Missouri-Rolla who recently received a patent for his research efforts to encapsulate plutonium in a special type of glass.
Dr. Delbert E. Day, Curators' Professor of ceramic engineering at UMR, received the patent from the United States Patent Office for his research into ways to dispose of excess plutonium from dismantled nuclear weapons.
Day's method involves the use of a special iron phosphate glass to chemically dissolve the nuclear waste.
Day, also a senior research investigator in UMR's Graduate Center for Materials Research, says it will take several decades and billions of dollars to dispose of all the radioactive waste that was created from the production of nuclear weapons and electricity in the United States during the past 50 years.
But a special family of glasses hold promise as the means to safely dispose of much of the waste. The U.S. Department of Energy awarded UMR a three-year grant to research the unique iron phosphate glasses developed at UMR.
According to DOE, "If geologic disposal is the option selected for disposition of plutonium, this research may result in a less expensive and safer disposal." .
"The permanent disposal of the radioactive wastes generated over the past 50 years is a major problem that will be with us well into the 21st century," Day says. It will be expensive, he adds, "but we must find a method to safely dispose of these radioactive wastes, which will be potentially dangerous for hundreds of years."
At UMR, Day is directing research to develop glasses to encapsulate this nuclear waste.
"We prepare simulated nuclear waste and determine how much of that waste can be dissolved in the iron phosphate glasses," Day says. Through a process called vitrification, Day and his colleagues melt a mixture of simulated radioactive waste with a non-radioactive base material to form a glass that immobilizes the waste.
The glass must have an exceptionally good chemical durability and not release any of the radioactive waste to the biosphere, Day says.
"Iron phosphate glasses have the potential to be used with certain types of nuclear waste," Day says. "The glass can then be stored in a repository deep in the Earth for thousands of years, with little or no chance of the radioactive materials escaping into the environment."
Day hopes to develop iron phosphate glasses which are well suited for containing nuclear wastes. Iron phosphate glasses have an exceptionally good chemical durability and can dissolve certain types of nuclear waste which are not well suited for the borosilicate glasses that have been developed for nuclear waste disposal.
Even though Day cautions that one type of glass may not work with every type of nuclear waste, he adds, "Our ultimate goal is to develop glasses that can contain large amounts of specialized nuclear wastes, are environmentally safe to use, and lower the cost of disposal."
The research project to develop iron phosphate glasses at UMR is being conducted in collaboration with the Westinghouse Savannah River Co. in Savannah, S.C., and Battelle Pacific Northwest National Laboratories in Richland, Wash.
"Nuclear waste is presently stored in large steel tanks at both sites. Some of those tanks are leaking, so a better method of permanently disposing of that waste is needed," Day says.
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