Glass Containers May Be The Answer For Nuclear Waste Disposal, Researcher Says

Dr. Delbert E. Day, Curators' Professor of ceramic engineering at UMR,received the patent from the United States Patent Office for his researchinto ways to dispose of excess plutonium from dismantled nuclear weapons.

Day's method involves the use of a special iron phosphate glass tochemically dissolve the nuclear waste.

Day, also a senior research investigator in UMR's Graduate Center forMaterials Research, says it will take several decades and billions ofdollars to dispose of all the radioactive waste that was created from theproduction of nuclear weapons and electricity in the United States duringthe past 50 years.

But a special family of glasses hold promise as the means to safely disposeof much of the waste. The U.S. Department of Energy awarded UMR athree-year grant to research the unique iron phosphate glasses developed atUMR.

According to DOE, "If geologic disposal is the option selected fordisposition of plutonium, this research may result in a less expensive andsafer disposal."  .

"The permanent disposal of the radioactive wastes generated over the past50 years is a major problem that will be with us well into the 21stcentury," Day says. It will be expensive, he adds, "but we must find amethod to safely dispose of these radioactive wastes, which will bepotentially 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 wastecan be dissolved in the iron phosphate glasses," Day says. Through aprocess called vitrification, Day and his colleagues melt a mixture ofsimulated radioactive waste with a non-radioactive base material to form aglass that immobilizes the waste.

The glass must have an exceptionally good chemical durability and notrelease any of the radioactive waste to the biosphere, Day says.

"Iron phosphate glasses have the potential to be used with certain types ofnuclear waste," Day says. "The glass can then be stored in a repositorydeep in the Earth for thousands of years, with little or no chance of theradioactive materials escaping into the environment."

Day hopes to develop iron phosphate glasses which are well suited forcontaining nuclear wastes. Iron phosphate glasses have an exceptionallygood chemical durability and can dissolve certain types of nuclear wastewhich are not well suited for the borosilicate glasses that have beendeveloped for nuclear waste disposal.

Even though Day cautions that one type of glass may not work with everytype of nuclear waste, he adds, "Our ultimate goal is to develop glassesthat can contain large amounts of specialized nuclear wastes, areenvironmentally safe to use, and lower the cost of disposal." 

The research project to develop iron phosphate glasses at UMR is beingconducted in collaboration with the Westinghouse Savannah River Co. inSavannah, S.C., and Battelle Pacific Northwest National Laboratories inRichland, Wash.

"Nuclear waste is presently stored in large steel tanks at both sites. Someof those tanks are leaking, so a better method of permanently disposing ofthat waste is needed," Day says.