After 30 years of service, and more than a decade passing since playing a critical role in helping Mexico successfully eradicate the devastating parasitic screwworm, three Husman irradiators near Chiapas Mexico still contained more than 50,000 curies of cesium-137. Since the Cs-137 content represented an undue risk, which included potential use by terrorists or other nefarious organizations, moving them to a secure U.S. location for final disposition was a top U.S Department of Energy priority. To be repatriated, however, each first had to be shown to meet the current Type B transportation requirements. At the time of design and manufacture each irradiator was subjected to significant review and analysis to ensure compliance with 10 CFR 71.73, with each package demonstrated to be able to withstand the prescribed hypothetical accidents. The NRC Certificate of Compliance (CoC) for use as shipping containers, expired on June 30, 1991. With each irradiator being large and weighing over 16,000 pounds, reconfiguration of the contents or re-packing into currently certified Type B over packs was deemed to neither be feasible or safe to perform due to the location and radioactive content of the Husman Irradiators. After: 1) a detailed original design review; 2) a review of the history of safe use of the Husman Irradiators for transport; 3) the absence of any unfavorable operational data; and, 4) confirmatory structural analyses, it was determined that authorizing a one-time shipment shipping of the subject Husman Irradiators to their disposal location would ensure equivalent safety and meet the requirements specified in DOE Order 460.1C, thereby allowing for the exemption. This paper details those activities performed to justify the exemption.
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