On June 23rd at approximately 8 p.m., at a temporary job site [located at a refinery in Sinclair, Wyoming] a Kakivik Asset Management radiography crew experienced the premature tripping of the automatic locking device on a INC IR-100 exposure device.
During retraction of the source it was noted that the locking device had returned to the trapped position. When the crank handles were moved back and forth to insure that it had, it was noted that the source traveled back out of the exposure device. The radiographer immediately took control of the cranks and the assistant moved back to the unrestricted area. The source was returned to the collimator and the lock reset to capture the source. Upon retraction the event occurred again. This happened three times.
The radiographer with help from other crew members established a secure unrestricted area. The Night Supervisor, the Lead Radiographer and RSO were notified. Prior to their arrival the radiographer on-site turned the key and this effectively left the source in the camera but not in the safe and secure position.
The radiography was being performed at a fabrication shop during a turnaround and the RSO made the decision to have the exposure device placed in the lead lined transportation box and moved to a more secure location away from the General Public.
The vehicle was surveyed and the radiation levels for the driver were < 1 mR/Hr. The vehicle was locked and placed under constant surveillance until INC [manufacturer] could be contacted. RSO contacted INC at 7 a.m. the following morning and explained the situation. Their RSO indicated that the Lead Radiographer under his guidance could reset the lock and secure the source in the safe and secure position. This was accomplished successfully.
Kakivik's Material License (#50-27667-01) does allow for the retrieval of sources.
At no time was the General Public in any danger of coming into the restricted area.
The lead radiographer, radiographer and assistant radiographer received 80, 65 and 55 Mr on the 23rd of June respectively and 80, 25 and 5 Mr on the 24th. [Doses for the lead radiographer on the 23 and 24th June were accumulated during event response. Doses for the radiographer and the assistant radiographer were a mix of normal radiography and event response on 23 June, and doses on 24 June were due to event response.]
The camera has been removed from service and returned to INC for evaluation. The camera received annual maintenance at the INC facilities November 5, 2007.