It may not inspire feelings of health and security, but America's nuclear future may depend on how much yogurt we eat, and how much coffee we drink. That is because Rust Federal Services Inc. of Grand Junction, Colo., is aiming to commercialize a method of encapsulating low-level radioactive wastes in scrap low density polyethylene. The LDPE plastic used in the process, such as coffee can and yogurt container lids, currently is not recycled in Colorado.
Rust has been working with Kaiser-Hill Co. LLC, the contract consultant hired by the federal government to coordinate the cleanup and environmental rehabilitation of the Rocky Flats nuclear weapons plant north of Denver. Rust, an engineering and consulting firm, specializes in the disposal of radioactive waste. It has been using the plastic encapsulation method developed by the Brookhaven National Labor-atories and Kaiser-Hill in preparing wastes from Rocky Flats in special landfills in Utah and Nevada.
``Essentially, it is a fairly simple process,'' said James Navratil, chief scientist for Rust. ``The plas-
tic is shredded and extruded, and the radioactive material also is shredded and mixed in the plastic as it is poured into ordinary 55-gallon steel drums. When the material is stabilized there is no lleaching of radioactivity outside of the plastic.''
Larger solid or metal pieces, such as lead shielding, are placed
in specially constructed plywood boxes, which then are coated with epoxy resins to eliminate escape of radiation.
He said Rust will use about 18,000 pounds of LDPE lids, caps and cups during its one-year contract at Rocky Flats to stabilize and encapsulate a like amount of radioactive waste.
The low-level waste is mixed in 1-to-1 ratios with plastic, according to Navratil.
Most of the radioactive material comes from incinerator ash, nitrate salts, wastewater sludges, debris, soil, ground glass and beryllium fines that accumulated low levels of radiation in use at the now-closed Rocky Flats facility.
``The glass is better for the high-level wastes, because they can degrade plastic and other materials, but we find that with the low-level material, plastic is better, because the radioactivity is not high enough to degrade it, and it is not water-soluble and does not crack,'' Navratil said.
In the balance, the process also provides a use for the cups and lids, which normally might be landfilled.
Navratil said Rust is looking at the possibility of using the LDPE waste to encapsulate low-level radioactive waste such as tools and clothing used in commercial nuclear power plants, as well as low-level radioactive waste from medical and research facilities. Rust is working with an affiliated company, Waste Management of Colorado Inc., in studying the feasibility of collecting LDPE for commercial use in the nuclear waste application.
Both companies are affiliates of Oak Brook, Ill.-based WMX Technologies Inc., the world's largest waste-management service firm.
``Since much more LDPE is used in film and sheet products than in rigid products like lids and cups, we are trying to determine if we can adapt waste grocery bags and other films to the process,'' Navratil said.
``We have an advantage because Waste Management collects wastes for the whole area,'' he said.