The following information was received from the State of
Arizona via email:
On July 22, 2015, the licensee reported that they lost one gaseous tritium light source on approximately July 12, 2015. The licensee was removing each source from its subsequent device in order to make disposal more efficient. The lost source was part of a TLS Model 42000 drogue light. The model 42000 drogue light consists of two 450 millicuries (November 1988 assay date) mb-Microtec Model T4376-1 gaseous tritium light sources mounted in a stainless steel assembly. The sources are held in place with silicone. To remove the sources from the drogue light, the silicone (containing two sources) is removed from the stainless steel housing. The silicone is then placed in solvent to soften it. Once the silicone is soft, the sources are removed with little effort and with little or no silicone adhering to the source.
The sources were placed in the solvent on July 12, 2015 and the nonradioactive components of the assemblies, including the silicone, were discarded as regular trash on that date. The source removal and consolidation was completed for all legacy sources on July 22, 2015, at which time, a complete inventory was performed and one source was discovered to be missing. The missing tritium source has a current activity of 100 millicuries.
The Agency [Arizona Radiation Regulatory Agency is continuing to investigate the event.
Arizona First Notice: 15-017
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