The following information was received from the
Arizona Radiation Regulatory Agency via e-mail:
At approximately 8:00 AM on August 23, 2012, the Agency was informed that the Licensee had one damaged light source, two light sources unaccounted for, and identification of an intake of radioactive material by two TLS Systems employees.
The Licensee was taking back 148 drogue light assemblies for disposal/recycling. After receiving the sources, the Licensee noticed minute fragments of a light source on a stainless steel bench top on which the sources were being examined. The fragments were placed in empty liquid scintillation vials and an initial decontamination of the workbench was performed. In addition, an inventory of the sources was performed and 297 intact sources were counted. A total of 298 sources implied 149 drogue light assemblies, not 148 as indicated by the company who returned the sources. Also, 150 radiation labels, stainless steel housings, and Lucite inserts were counted, which would indicate 300 light sources.
Each drogue light assembly contained two mb-Microtec Model T-4376-1 tritium light sources. The sources had an initial activity of 450 millicuries each. The drogue lights are approximately 4 years old.
Bioassays were given to individuals present in the lab and are currently awaiting results.
The investigation into this event is ongoing. The U.S. NRC and AZ governor's office have been notified.
AZ Report Number: 12-013
THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL
Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf
This source is not amongst those sources or devices identified by the
IAEA Code of Conduct for the Safety & Security of Radioactive Sources to be of concern from a radiological standpoint. Therefore is it being categorized as a less than Category 3 source