Zapping contamination with lasers may be just the answer for safely and efficiently treating some of the waste awaiting disposal across the country.
"Not only are lasers proving effective at decontamination, but they offer some important advantages in terms of safety and reduction of secondary waste," says Martin Edelson, Director of the Ames Lab Environment Technology Development Program and the originator of research into using lasers for separating radioactive and chemical contaminants from metals. Unlike many traditional decontamination techniques, the Lab's new laser cleaning method uses no harmful solvents, creates little secondary waste and significantly reduces exposure of workers and expensive equipment to contamination.
Edelson's research team has investigated both surface and bulk decontamination with lasers. For surface cleaning, the researchers use a pulsed laser beam to precisely remove the contaminated layers of a metal while high-efficiency particulate air filters capture the removed particles and prevent them from resettling on the cleaned area.
Moving this research from the lab bench to the field, the Ames researchers are now working with DOE's Idaho National Environmental and Engineering Lab (INEEL) to develop and demonstrate a field operational surface laser decontamination unit. An example of successful technology transfer, INEEL heard about Edelson's laser ablation work and turned to him for help in developing a technique for decontaminating stainless steel materials (walls, equipment, vessels, tanks, etc.) of an inactive nuclear fuel reprocessing facility.
The collaborative work grew into a joint patent application (Martin Edelson and Ho-ming Pang, Ames; Russ Ferguson (Lockheed Martin Idaho Technologies Co.) and a technology that is now ready for commercial development. Carl A. Dunn, President of ZawTech International Inc., has recently licensed the technology to apply laser surface cleaning to a variety of industrial projects.
"Laser Ablation System and Method of Decontaminating Surfaces," U.S. patent No. 5,780,806 awarded July 14, 1998. Inventors are Russell Ferguson (Idaho Falls), Martin Edelson, and Ho-ming Pang.
- Improved Safety -- Can be performed remotely, separating workers from contamination.
- Less Secondary Waste -- Unlike most traditional techniques, this generates minimal additional waste (only the air filters are contaminated during the process).
- Less Equipment Contamination -- Expensive equipment not exposed to contamination.
- No Hazardous Chemicals -- Unlike traditional techniques, this decontamination method uses no chemicals and therefore, raises no concerns over safe chemical handling or disposal.
- Reduced Waste Volumes -- The effectiveness and cost-efficiency of this technique may allow certain materials to be recycled rather than stored or disposed of.
- Lower Waste Classifications -- Effective and cost-efficient surface decontamination may allow some difficult-to-handle categories of waste (primarily mixed waste) to be reclassified as easier-to-handle low-level or hazardous wastes.
- Reuse of Valuable Metals -- Metals unusable because of surface contamination may be cleaned sufficiently to allow reuse.
- Reduced Costs-- Automated efficient technique reduces costs of not only decontamination but also overall waste storage and disposal as waste volumes and classifications are reduced.
This new laser technique for safe, effective metal decontamination produces little secondary waste and can reduce waste volumes (or at least lower waste classifications) and therefore, reduce the hazards and costs of waste storage and disposal.