Print View Posted on: 25 September 2015
The Lead Radiographer and three assistant radiographers were completing two exposures lasting 35 seconds each. The set-up time for the exposures was approximately 15 to 18 minutes. After completing two exposures, one individual noticed that his pocket dosimeter read off scale, a second individual read their dosimetry at 0.5 mSv (50 mrem), the third individual read their pocket dosimeter as off scale, and the fourth individual was not wearing a dosimeter. Two individuals were wearing functioning rate meters and two were not. Additionally, the radiography crew was using a survey meter that was determined after the event to have had an electrical short and therefore was not functioning properly. Dosimetry for the three individuals that were wearing dosimetry was sent for emergency processing. The dosimetry readings were determined to be: 1) 112 mSv (11.2 rem), 2) 50 mSv (5.0 rem), and 3) minimal. The minimal reading was determined to be invalid since it was discovered that this individual left their dosimetry in their hard hat which they did not have with them at the time of the two exposures. For the fourth individual, who was not wearing any dosimetry, the licensee has estimated a preliminary dose of up to 450 mSv (45 rem). The licensee is in the process of confirming the dose to the third individual and the estimated dose to the fourth individual. UPDATE: The State of Alabama interviewed the RSO and all involved personnel. A re-creation of the event revealed that the source had been outside the camera, but not in the guide tube. The four radiography personnel involved have been seen by an occupational physician and have submitted blood samples that were sent to REAC/TS for cytogenic biodosimetry. REAC/TS determined that all four individuals received exposures of less than the 200 mSv (20 rem). The licensee assigned the following doses to the four individuals: 1) 112mSv (11.232 rem); 2) 200 mSv (20 rem); 3) 50 mSv (5 rem); and 4) 50 mSv (5 rem). The primary causes of the incident appear to be the failure to use an operable survey meter and the failure to follow procedures. Training was provided to appropriate staff although some staff were terminated as a result of this event. NRC EN50904