The licensee reported that an
Ohmart density
gauge (Model
SH-F2, Serial Number 2479GK) had last been seen during an inventory and shutter check on November 17, 2003. The
gauge contained a 1.85 GBq (50 mCi),
Cs-137 sealed source. Facility records indicate the device's electrical signal was lost on December 12, 2003, at 4:30 pm. At that time, a physical investigation, to investigate the signal loss, was not performed. The next routine inventory was attempted on May 17, 2004. At this time the
gauge was found to be missing.
The missing gauge had measured 'weight rejects' at a remote part of the facility. Rejects are routinely sent to an eastern Washington landfill by truck. The gauge seems to have been dislodged from its angle-iron attachment, by large reject material, and then inadvertently taken to an eastern Washington landfill by the rejects truck.
Gauge measurements were not vital to operations, so the loss of signal had gone ignored until the May 17th inventory attempt.
CORRECTIVE ACTION TAKEN by licensee:
1. A special training session will be given, during the licensee's next monthly safety meeting, for those employees associated with fixed gauge operations. The training will emphasize the importance for employees to investigate when gauge process measurements are lost.
2. Special informational postings will be placed at key locations within the facility, near process control equipment receiving fixed gauge electrical signals, so facility employees shall be reminded to immediately investigate the loss of a gauging device's signal.
Isotope and Activity Involved: Cs-137, 1.85 GBq (50 mCi)
Overexposures? (number of workers/members of the public; dose estimate; body part receiving dose; consequence): None likely.
Lost, Stolen or Damaged? (mfg., model, serial number): Lost (or Stolen) Ohmart density gauge (Model SH-F2, Serial Number 2479GK)
DISPOSITION/RECOVERY: Searches by licensee with the assistance of department staff were performed with Ludlum Model 19, Micro R meters and other detection instrumentation. These searches were unsuccessful.
A search at the Licensee's facility in Port Townsend, Washington was conducted on May 25, 2004. A search at the landfill was performed on July 29, 2004.
Event Report Number: WA-04-028