sixth-lecture-npre442-sp11 - Low-Level Radioactive Waste...

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1 Low-Level Radioactive Waste Management “Why,” said the Professor hotly, “one would say you were already beginning to be afraid.” —Prof. Von Hardwigg in “Journey to the Center of the Earth” by Jules Verne. Early LLRW Disposal In the 1950s, shallow land burial, at times careless and undocumented. LLRW from the "National Reactor Testing Station” in Idaho, c. 1950.
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2 Early LLRW Disposal Cardboard boxes and open drums in unlined ditches. LLRW from Hanford, c. 1950 Desirable characteristics for land burial True for municipal wastes, coal ash, incinerator ash- --and solid wastes that contains potential groundwater contaminants: 1. Relatively water-impermeable soil to reduce the chance that radionuclides are leached and transported from the disposal area into groundwater
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3 Desirable characteristics for land burial 2. Disposal above water table; isolating the wastes from precipitation, groundwater, and surface water. 3. Local geology is well known; subsurface layers of material and their hydrogeologic properties are documented and understood; a site assessment. 4. Stable area (no earthquakes, soil erosion, landslides)–flat; a risk assessment has been conducted. Background and history of LLRW burial 1962: Beatty, Nevada. First commercial LLW site. Closed in 1992 because of management problems. Employees removed a cement mixer and other tools which were brought to the site as radioactive waste, and used them in local construction projects.
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4 Beatty received 4.3 million cubic feet of low-level waste which was disposed of in shallow burial sites. Eighty percent of Beatty's radioactive waste came from commercial nuclear power plants. Background and history of LLRW burial 1963: Maxey Flats, Kentucky. Closed in 1977 West Valley, New York. Closed in 1975 Both were closed because of “complex geology,” surface-cap collapse, and groundwater accumulated in the disposal trenches.
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5 Buried at Maxey Flats “An estimated five million cubic feet of material were disposed. Most was solid waste; however, other waste types were disposed, some were highly radioactive. Approximately 533,000 pounds of source material (consisting of uranium and thorium or ores containing them), 22 mega curies of by-product materials, and 950 pounds of special nuclear material (plutonium and enriched uranium) were buried in an area known as the Restricted Area.”
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6 Cross-section of Maxey Flats
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Operational problems at Maxey Flats During the operation of the facility, workers capped each disposal trench with a layer of soil after it was filled, but the earth eventually collapsed into the ditches. Water collected in the trenches, leaching radionuclide’s into the surrounding environment. “Bath tub effect” at Maxey Flats
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sixth-lecture-npre442-sp11 - Low-Level Radioactive Waste...

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