The licensee determined today, 3/28/2018, that they had lost an
Am-241 thickness
gauge source. A few months ago the
Am-241 thickness
gauge source had been replaced with a non-radioactive thickness
gauge source. The licensee had observed the
Am-241 thickness
gauge source at the plant after it was removed, but when they tried to locate it last week could not find it. They searched the site, including using a radiation detector to search with, and did not locate the
Am-241 thickness
gauge source.
The gauge is an NDC Technologies, probe Model 103, with an Am-241source. The device S/N is 12131, and the source S/N is 7199 LQ with an Assay date of 10/6/1998. No specific source strength was included in the data the licensee had, but they indicated the source strength was low. NDC Technologies license GL-657303-19 indicates the Am-241 source activity is 150 micro Ci.
The licensee stated that they are continuing to search for the Am-241 thickness gauge source, and they are preparing a written report. The licensee stated that they have revised their administrative policy for control of radioactive material and are scheduling retaining for their radiation safety officers.
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