The following was received from the
Oregon Health Authority, Radiation Protective Services (
Oregon RPS) via email:
On October 8, 2021, during a low-level radioactive waste (LLRW) broker's visit to an Oregon scrap metal site to package and ship accumulated radioactive materials to a LLRW site, a fixed gauge was found among the items in storage. The technician notified the broker's office of the discovery and the broker notified Oregon RPS on October 11, 2021 at 1120 [PDT] hours. The gauge shows some wear with the gauge shutter lever broken but the shutter appears intact and closed with the source inside. Information on the gauge/source is as follows:
Manufacturer: Ohmart
Model 3340
Serial number: 70453
Source: Cs-137
Activity: 50 mCi
Source holder: SR-1A
Source manu: 3M
Source model: 4F6S
Source serial: S-601
Highest dose rate at contact: 70 mrem/hour (at collimated end)
Highest dose rate at 1 ft: 18 mrem/hour
Highest dose rate at 1 m: 2 mrem/hour
The gauge was placed shutter-side down in a secured metal storage vault on site. Dose rate on the surface of the gauge measured at less than 2 mrem/hour. The licensee is in contact with the manufacturer to arrange disposal of the gauge.
The gauge was originally installed in 1981 at a silver mining mill located south of Ely, NV. There were four additional gauges installed at the Nevada site at that time. RPS has contacted the Nevada Agreement State Radiation Control office and that office is investigating.
Oregon State Event Report No: OR-21-0051
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