ML18236A551

Request for Approval for Use of Alternative A2 Value for Isotope Br-80m Under Appendix a to 10 CFR 71

ML18236A551
Person / Time
Site:	U.S. Geological Survey
Issue date:	08/09/2018
From:	Manning C US Dept of Interior, Geological Survey (USGS)
To:	Document Control Desk, Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation
References
Download: ML18236A551 (2)

Text

E*USGS science for a changing world Department of the Interior US Geological Survey Box 25046 MS-974 Denver CO, 80225 August 9, 2018 ATTN: Document Control Desk Director, Division of Spent Fuel Management Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 SUBJ.: Request For Approval For Use of Alternative A2 Value For Isotope Br-80m under Appendix A to 10 CFR 71 To Whom It May Concern:

The U.S. Geological Survey TRIGA Reactor (GSTR), Docket 50-274, License R-113, would like to request approval to use a different A2 value for Br-80m than the general A2 value in Table A-3, Appendix A to Part 71.

As part of the facility's operations, radioactive tracer materials are produced for industrial processes; these are shipped as Normal Form materials in DOT Type 7A Containers. One of these tracers is the isotope Br-82, produced by irradiating a bromine target compound in the reactor. Incident to the production ofBr-82 are smaller amounts of the isotope Br-80m. Although Br-82 has an entry for its A2 value in Table A-1, Appendix A to Part 71, Br-80m does not. Thus, the general value for A2 listed in Table A-3, Appendix A to Part 7Iis to be used for Br-80m. This presents a challenge because the general A2 value (0.54 Ci) is unduly restrictive compared to the A2 value for Br-82 (11 Ci).

The general A2 value is considered unduly conservative for calculations in this particular case because Br-80m presents less of a hazard in transportation than Br-82 does. For instance, the Annual Limit on Intake set by the NRC for Br-82 (3000 microCuries) is over 3 times lower (and thus morr>: restrictive) than Br-80m (10,000 microCuries).

Additionally, the half-life ofBr-80m (4.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) is so short compared to Br-82 (35 hours4.050926e-4 days <br />0.00972 hours <br />5.787037e-5 weeks <br />1.33175e-5 months <br />), that the hazard with the former isotope will drop off quickly in transit. The external hazard provided by gamma rays is also much higher for Br-82 than Br-8.0m (approximately 1295 keV total energy per disintegration for Br-82 vs under 20 keV for ;J/t//55LD Br-80m).

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In order to remedy the effects of the overly conservative default A2 value for Br-80m, the GSTR is requesting approval to use the A2 value for Br-82 (11 Ci), the more hazardous isotope, as the A2 value for Br-80m. This change would still produce a conservative effect on the safety of transporting these isotopes without being overly conservative to the point of being unwieldy. This approval would not supersede any other regulations.

Please contact me if you need any more information.

Sincerely, c~1!::i Health Physicist US Geological Survey TRIGA Reactor Phone:303-236-4726 Email: cmanning@usgs.gov