The following information was received via email from the State of Colorado:
On May 21, 2012, the Colorado Department of Public Health and Environment was notified of an incident which occurred at Public Service Company of Colorado, Colorado License 032-01. The event occurred at the Hayden Station located in Hayden, CO on March 23, 2012. During boiler repairs, two contract workers removed six radiation level detector fixed gauges from an ash hopper without authorization. The gauges were discovered the following day by plant personnel, and it was noted that the shutters were in the open position. Each gauge, Texas Nuclear Model 5197, contained 100 mCi of Cesium-137. Based on dose reconstruction estimates provided by the licensee, it is likely that at least one of the contract workers received an exposure in excess of 2.0 mrem in one hour and up to 6.0 mrem in one hour. No other details are available at this time.
Event Report ID No.: CO12-I12-09
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
Note: This device is assigned an
IAEA Category 3 value based on the actual radioactivity of the source, not on the device type. (Reference
IAEA RG-G-1.9)