ML20237C134
| ML20237C134 | |
| Person / Time | |
|---|---|
| Issue date: | 08/11/1998 |
| From: | Dennise Orlando NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Mora P AFFILIATION NOT ASSIGNED |
| References | |
| REF-WM-3 NUDOCS 9808200237 | |
| Download: ML20237C134 (3) | |
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i UNITED STATES g
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NUCLEAR REGULATORY COMMISSION o
2 WASHINGTON, D.C. 20666-0001
- Qo August 11, 1998 Ms. Patricia Mora, M.Sc.
Escuela de Fisica Universidad de Costa Rica San Pedro de Montes de Oca San Jose, Costa Rica Central America
Dear Ms. Mora:
I am writing in response to your recent questions pertaining to the regulation of Krypton-85
(*5Kr) by the U.S. Nuclear Regulatory Commission (NRC) in the United States. Specifically, you posed the following questions:
1.
What is the maximum activity of 85Kr that can be released into the air; 2.
What are the maximum levels of 85Kr that can be present in the workplace; 3.
What equipment is necessary to monitor Kr in air; and, 85 4.
Do I know what the limits for 85Kr are in other countries.
To address your first question, NRC's regulations at 10 CFR 20.1302 and 10 CFR 20, Appendix B establish the maximum allowable levels of '5Kr that can be released into the air from a licensed nuclear facility. 'As stated in these regulations, the annual average concentration of
- Kr that may be released at the boundary of the unrestricted area of the licensee's facility may not exceed 7E 7 microcuries per milliliter (pCi/ml) of air.
NRC regulations at 10 CFR 20.1201 and 10 CFR 20, Appendix B address occupational dose limits. NRC regulations at 10 CFR 20.1201(d) state that the derived air concentration (DAC) shall be used to demonstrate compliance with the NRC's occupational dose limit. As stated in the NRC's regulations in 10 CFR 20 Appendix B, the DAC for esKr is 1E-4 pCl/ml of air.
Regarding equipment necessary to monitor '5Kr in air, internal gas counting is a sensitive technique that can be used to assay concentrations of noble gases. Radioactive gases can be detected when incorporated into the fill gas of an ionization chamber. Exit or entrance ports are provided into the chamber so that the sample gas may be introduced on a continuous basis, and the volume of sample gas measured to eventually determine the concentration of
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radioactive material. However, this technique can be infiuenced by effects due to moisture, aerosols, smoke, and the inherent sensitivity of the chamber to ambient radiation. NRC's policy is not to recommend any particular manufacturer or product; however, a further source on information might be the Health Physics Society at 1313 Dolley Madison Boulevard, 3
McLean, Virginia 22101, phone (703) 790-1745.
9808200237 980811
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P. Mora -3,*
3 Regarding your last question, I am unaware of the limits for "Kr in other countries.
If you have any questions, please feel free to contact me at (301) 415-6749.
Sincerely, b'
Dominick A. Orlando, Project Manager Low-level Waste and Regulatory issues Section Low-level Waste and Decommissioning Projects Branch Division of Waste Management Office of Nuclear Material Safety and Safeguards 1
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I August 11, 1998 I
i il Mora j Regarding your last question, I am unaware of the limits for Kr in other countries.
85 If you have any questions, please feel free to contact me at (301) 415-6749.
Sincerely, l
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J Dominick A. Orlando, Project Manager Low-level Waste and Regulatory Issues Section
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Low-level Waste and Decommissioning l
Projects Branch j
Division of Waste Management Office of Nuclear Material Safety and Safeguards 1
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