Treatment and Stabilization of Potentially Pyrophoric Radioactive Metal Chips and Turnings
- Perma-Fix Environmental Services Inc., 701 Scarboro Road, Suite 300, Oak Ridge, TN (United States)
As part of the continuing mission to decontaminate, decommission, and restore environmental quality at multiple sites throughout the U.S. Department of Energy (US DOE) nuclear complex, approximately 2,000 containers of potentially pyrophoric radioactive metal chips and turnings, weighing over 192,000 kilograms have been identified. These wastes, mostly depleted uranium (DU) and thorium metals, must be treated to remove or immobilize a wide range of hazardous and toxic regulated waste constituents without igniting the radioactive metal. Also, the treated metal wastes must be placed in an inert condition to prevent any future pyrophoric problems during storage, transportation, and disposal. All secondary wastes resulting from treatment activities must have a pathway to final disposal or destruction, in accordance with all applicable US federal and state laws, and regulations. To further this mission and to begin reducing the pyrophoric radioactive metal inventories throughout the US DOE system, a contract was awarded to Perma-Fix Environmental Services, Inc. to develop appropriate treatment methods, prove those methods in a First Article Test (FAT), and treat US DOE's existing inventory of pyrophoric radioactive metal wastes. The FAT was performed successfully between October 2002 and December 2002 using four containers of waste from the Rocky Flats Environmental Technology Site. The treated chips and turnings from this FAT were shipped for disposal at a private land disposal facility in the State of Utah. Since the FAT, two full-scale treatment projects have been performed under the contract. Between November 6, 2003 and March 4, 2004, 478 containers of Hanford DU chip wastes in mineral oil and soil matrices were treated. The treated chip waste was returned for disposal at the permitted mixed waste landfill at the Hanford Site. Between February 5, 2004, and February 25, 2005, another 222 containers of Rocky Flats DU chip waste, comprised of three distinct physical waste forms, were treated and disposed at the same land disposal facility in Utah. Complicating this task was the wide variety of hazardous and toxic contaminants, and great variability in the physical waste form. The chemical contaminants included mineral oil, polychlorinated biphenyls (PCBs), numerous volatile and semi-volatile organic contaminants, and toxic metals. Three main physical waste forms were included in the US DOE pyrophoric radioactive metal waste inventory: (1) chips and turnings in oil, (2) chips and turnings in soil, and (3) chips and turnings in sludge. The successful treatment method had to be capable of removing oil, PCBs, and volatile organics without resulting in ignition of the pyrophoric metals. After successful removal of hazardous and toxic organic contaminants, the toxic metals remaining in the waste required further stabilization to limit their potential for long-term leaching in land disposal facilities. The final waste form and its packaging also had to comply with the waste acceptance criteria of the land disposal facilities at the US DOE Hanford Site, in Richland, Washington, and the private disposal facility in Utah. This paper will describe the treatment process, the challenges encountered and overcome, the lessons learned, and final quality of the treated chip waste. Disposal and/or destruction of secondary wastes from the treatment process will also be discussed. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 13023, Tucson, AZ, 85732-3023 (United States)
- OSTI ID:
- 21208556
- Report Number(s):
- INIS-US-09-WM-06016; TRN: US09V0867079343
- Resource Relation:
- Conference: Waste Management 2006 Symposium - WM'06 - Global Accomplishments in Environmental and Radioactive Waste Management: Education and Opportunity for the Next Generation of Waste Management Professionals, Tucson, AZ (United States), 26 Feb - 2 Mar 2006; Other Information: Country of input: France
- Country of Publication:
- United States
- Language:
- English
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