Audeen W. Fentiman
Matthew E. Jorat
Joyce E. Meredith
Low-level radioactive waste is produced as a result of many commercial processes, and can be generated in both solid and liquid forms. Federal regulations, as well as economics, require minimizing the total amount of low-level waste produced, stored, and disposed of. The same approaches are taken to minimize low-level waste as can be taken to minimize other industrial wastes or ordinary household waste. These approaches include the three "R's", reduce, reuse, and recycle. First, efforts are made to reduce production of low-level waste. Next, the total volume of low-level waste that must be disposed of is decreased by decontaminating and reusing and/or recycling the non-radioactive contents of the waste. Finally, the remaining low-level waste undergoes various treatments to decrease its volume prior to storage, transportation, and disposal.
This fact sheet will describe the processes used to minimize low-level radioactive waste.
One way to reduce low-level radioactive waste is to replace the radioactive material with something that is not radioactive. However, radioactive material is generally used only in processes or products that depend on radiation for their success. Replacement with a non-radioactive material is often not possible.
In processes that use radioactive materials, selection of the correct equipment may reduce production of low-level radioactive waste. For example, a crane should not be used to relocate a radioactive source when a small lift could perform the same task. The lift, being smaller, requires less decontamination and, therefore, the use of less cleaning material, leading to a smaller volume of disposed waste.
Once the correct equipment for a task has been determined, the next priority is proper operation of that equipment, which can reduce the amount of low-level radioactive waste produced. Low-level waste volume can also be reduced by replacing only the damaged parts of broken equipment. For example, instead of discarding an entire pump, only the damaged seal should be disposed of.
Another method of reducing low-level radioactive waste generation is isolation. Equipment or material should not be taken into a contaminated environment unless it is absolutely necessary. Monitoring systems can be installed to provide early detection of releases of radioactive material which could reduce the amount of surrounding material that is contaminated during the leak. As a result, there will be less low-level waste from cleanup operations. Additionally, automation of various processes can reduce the number of people who must handle radioactive materials, thus reducing the amount of protective clothing needed.
Segregation is another effective method for reducing low-level radioactive waste volume. Segregation refers to the process of separating radioactive waste from non-radioactive trash. This is important because when the non-radioactive and radioactive trash are mixed, the non-radioactive trash may become contaminated, and all of the trash must be treated as low-level waste.
Reusing and recycling are other methods of decreasing the amount of low-level radioactive waste that requires disposal. By cleaning and reusing contaminated equipment and supplies, the amount of material requiring disposal can be greatly reduced. For example, some protective clothing can be washed and reused, and metal tools can be decontaminated. It is also possible to recycle cleaning agents that are used in decontamination processes and use them several times before disposal is required.
When no further recycling or reuse is possible, the two methods most frequently used to reduce the volume of the remaining solid low-level radioactive waste are compaction and incineration. Compaction involves compressing low-level waste, thereby reducing the volume. Incineration is the process of burning solid low-level waste to reduce its volume. It should be noted that while compaction and incineration reduce waste volume, neither process reduces the activity of the waste.
Compaction and incineration are sometimes performed in conjunction with shredding. Shredding means cutting solid low-level radioactive waste into smaller pieces. This provides better compression capability in the case of compaction, and a more uniform burn for incineration.
Two common methods for reducing the volume of liquid low-level radioactive waste are filtration and evaporation. During filtration, the liquid is passed through a porous material to remove radioactive particles. In evaporation, the liquid waste is heated until excess water has boiled off.
The remaining liquid low-level radioactive waste must be solidified before it can be sent to a disposal facility. The liquid is usually mixed with concrete, asphalt, or some other approved solid material for disposal. Mixing the liquid with another material to form a solid waste increases the total volume of material sent to the disposal facility. It is important to reduce the volume of the liquid before it is solidified so that the total volume shipped for disposal is as small as possible.
If you want to read more about minimizing low-level radioactive waste, some of the references listed below may be helpful.
Edward L. Gershey et. al., Low-Level Radioactive Waste From Cradle to Grave, Van Nostrand Reinhold, New York, 1990.
Low-Level Radioactive Waste Volume Reduction and Stabilization Technologies Resource Manual, DOE/LLW-76T, EG&G Idaho, Inc., Idaho Falls, December 1988.
Raymond L. Murray, Understanding Radioactive Waste, Battelle Press, Columbus, Ohio, 1989.
Waste Minimization for Commercial Radioactive Materials Users Generating Low-Level Radioactive Waste, EGG-WM-9185, EG&G Idaho, Inc., Idaho Falls, July 1991.
Dr. Audeen W. Fentiman is an Assistant Professor in Nuclear Engineering at The Ohio State University. Matthew E. Jorat is a Graduate Research Associate in Nuclear Engineering. Joyce E. Meredith is a Graduate Research Associate, Ohio State University Extension.
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Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Keith L. Smith, Director, Ohio State University Extension.
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