LIVERMORE, Calif. -Ten years after the world's worst accident involving a nuclear reactor, a collaboration of private business and researchers from the United States and Belarus is planning to test a potential way to decontaminate forests north of Chernobyl. The project will evaluate health, environmental, and economic consequences of a pilot biomass power plant designed to burn timber harboring almost all the radioactive residue, and capture radioactivity in the ash.
Belarus is an independent state just north of Chernobyl. It received about 70 percent of the radioactive fallout released during the Chernobyl explosion and subsequent fires. Altogether, the accident spewed an estimated 200 times the radiation unleashed by the atomic bombs that were dropped on both Nagasaki and Hiroshima, said Larry Baxter, a chemical engineer at Sandia National Laboratories. Regions severely contaminated in the April 26, 1986 accident represent approximately 25 percent of the total area of Belarus. The contamination is concentrated mainly in the heavily forested southeast portion of the country. Baxter and researchers at the Institute of Power Engineering Problems, which was part of the Soviet Academy of Sciences under the former Soviet Union, will join with Wheelabrator Environmental Systems Inc. of Hampton, N.H., to build the pilot plant to convert contaminated wood and litter from the forest floor into electrical energy. The wood and "duff" from the forest floor would be burned in this specially designed power plant that is fueled by biomass, or plant matter. Radionuclides, primarily cesium and strontium, would be captured in the ash, and could then be disposed of as low-level or very low-level waste, said Bill Carlson, vice president of Wheelabrator's western region.
Wheelabrator, which operates five biomass and 16 trash-to-energy plants, is contributing half _ $800,000 _ of the $1.6 million expense for the two-year project. The remaining half is being provided by the Department of Energy's Initiatives for Proliferation Prevention program, which is intended to deter nuclear proliferation by providing non-weapons-related work to people with scientific and technical expertise in the former Soviet Union. Sandia and Belarus will equally share this DOE funding. The project has been formalized in a Cooperative Research and Development Agreement, approved Sept. 18. The project's risks and benefits will be examined as it proceeds. The pilot plant could demonstrate a way to remediate contamination and thus reduce health risks posed by ingesting the radionuclides, whose weak radioactive emissions are otherwise easily shielded. A second benefit would be to potentially decrease Belarus' heavy dependence on imported energy, and consequently lessen the economic pressure to build additional nuclear power plants. The power generated by the biomass power stations is projected to cost less than the current or future average power generation costs in Belarus, providing an economic benefit to the country.
"The prime consideration is to not make the situation worse," commented David Brekke, a Sandia health physicist on the project. "If we can't do this in a safe and environmentally sound manner, it won't go." Already, Baxter said, Belarus has conducted a feasibility study exploring the use of biomass for electrical energy there. The country lies south of the Baltic Sea, between Poland and Russia, and occupies an area about the size of Utah. It imports roughly 90 percent of its energy, lacking any significant reserves of coal or other traditional fuels for power generation. "Biomass-derived power is ideally suited to their society," Baxter commented. "We think they will be able to produce electricity at a rate lower than the current cost in Belarus."
At Sandia, Baxter investigates the burning of a variety of biomass fuels, such as wood, straw, fruit pits, and nut shells, to generate electricity. He says "biomass combustion presents one of the largest potentials for expansion of renewable energy in the United States." Biomass fuels provide about 2 percent of the energy generated in California, where several companies operate a number of commercial plants, adds Carlson of Wheelabrator.
Besides citing the potential for Belarus to gain some energy independence by using biomass, Baxter described the project's humanitarian benefits. Most of the rural residents of Belarus live very close to the land and depend on the forest for fuel and supplies. Hence, although it is prohibited, he said some residents do enter the contaminated forests to gather food, such as mushrooms, and collect firewood, which can spread contamination through dispersion of airborne fly ash beyond the forests.
Fallout from the nuclear disaster is showing up in thyroid cancers and leukemia, particularly in children. Although thousands of people were evacuated after the accident, the government can't afford to build new cities to house everyone still living in affected areas (an estimated few million people). In addition, fertile agricultural land is largely unused because of the contamination. Overall, a full three-fourths of the country has been contaminated to a measurable level. One-fourth of that would exceed the U.S. EPA standards for annual radiation dose by the general population by anywhere from 2 - 100 times, Baxter said.
Wheelabrator will experiment with burning uncontaminated duff at its commercial plant in Anderson, Calif., Carlson said, where about 2,000 tons of biomass are burned per day. By contrast, Carlson said the pilot plant in Belarus may burn just two tons of material a day. At Sandia's Combustion Research Facility, Baxter and post-doctoral employees Steve Buckley and Melissa Lunden will model combustion characteristics, determining through computer simulation which plant design would minimize the emission of small, hard-to-capture particles. The model will be benchmarked against Wheelabrator's extensive database for heavy metals and available radionuclide data.
Left alone, the contaminated regions would take hundreds of years to return to acceptable levels of radioactivity, Baxter said. Otherwise, if converting contaminated wood to biomass power is feasible, he predicts the contamination might be gradually cleared in 30 to 40 years. Sandia is a multiprogram Department of Energy laboratory, operated by a subsidiary of Lockheed Martin Corp. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major research and development responsibilities in national defense, energy, environmental technologies and economic competitiveness.
Sandia/California Public Affairs
(510) 294-2932, Nancy_Garcia@Sandia.gov
Sandia Combustion Research Facility
David Allen, project manager
Wheelabrator Western Region headquarters
Sandia Environmental Surveillance