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21 November 2009

Answer to Question #2418 Submitted to "Ask the Experts"

Category: Policy, Guidelines, and Regulations

The following question was answered by an expert in the appropriate field:

My questions relate to regulated quantities of radionuclides. Appendix B of 10 CFR 20 gives limits for effluent concentrations and for aqueous waste in the sewers. Does the United States have similar disposal limits for solid waste? That is, at what point is waste considered to be safe for disposal in the regular waste stream? (In Canada these are called Solid Disposal Limits with values published for some 25 or so radionuclides.) You must refer to your license for any radionuclides that you might possess that are not on this list. Where would I find information on the maximum allowable quantities for possession of various radionuclidess that would be exempt from licensing in the United States? (In Canada these are called Exemption Quantities, with values published for an extensive list of radionuclides.)

In the United States, 10 CFR Part 20 provides, as examples, (1) radiological criteria for unrestricted use for license termination (the dose limit for unrestricted use per 20.1402 is 25 mrem per year to an average member of the critical group), (2) disposal by release into sanitary sewer systems, per 10 CFR 20.2003, (3) disposal by incineration, per 10 CFR 20.2004, and (4) disposal of specific waste such as ³H or ¹⁴C, per 10 CFR 20.2005. Other parts of the regulations, such as 10 CFR Part 35 for medical use applications, allow for disposal by decay-in-storage for short-lived radionuclides with a physical half-life of less than 120 days (typically decay for 10 half-lives or until the readings are indistinguishable from background; see 10 CFR Part 35.92).

As for your second question regarding information on the maximum allowable quantities that would be exempt from licensing in the United States, the NRC also calls these "Exempt Quantities and Concentrations" and they can be found in 10 CFR Parts 30 and 32, as well as 10 CFR 30.70 Schedule A, which provides a Table of exempt concentrations. To view these regulations, please see the NRC Web site .

Cynthia G. Jones, PhD

Answer posted on 9 April 2003. The information and material posted on this Web site is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Web site. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.