Overexposure to Worker

Print View Posted on: 08 January 2021

Event Date: 03 August 2020 Event Type: Radiation Source
Event Location: United States of America, Mobile, Alabama / Applied Technical Services, Inc. INES Rating: 2 (Final)

A radiographer and two assistants were working at an asphalt plant when a magnetic stand fell from the side of a tank and crushed a section of the guide tube of the radiography camera in use. Several attempts by the radiography crew to retract the source into the radiography camera using the crank were unsuccessful. Additional shielding was applied to the area of the tube containing the stuck source to reduce exposures and allow personnel to get closer to the area. The individuals were able to retract the source back into the camera by cutting the guide tube which allowed enough space to pull the source back through the crimp. Before performing the source retrieval, all three individuals moved their dosimetry to their wrist watches to account for accurate doses to the extremities. The dosimetry badges were sent to Landauer for emergency processing. The badges showed the individuals involved received whole body doses of 63.577 rem (635.77 mSv), 10.439 rem (104.39 mSv), and 2.608 rem (26.08 mSv) to the extremities. The whole-body doses obtained from the direct read dosimeters worn on the chest were 2.519 rem (25.19 mSv), 2.178 rem (21.78 mSv), and 0.798 rem (7.98 mSv). All three individuals involved were removed from radiography operations for the remainder of the calendar year. Corrective actions by the licensee included the modification of procedures and personnel retraining; ensuring that the magnetic stand is rated for the weight placed on it; ensuring the stand surface is free of debris and rust; and applying stress to the stand to determine the breaking point. The highest extremity dose received exceeds the U.S. statutory limit of 50 rem (500 mSv). NRC EN54813

INES Rating: 2 - Incident (Final) as per 21 December 2020
Release beyond authorized limits? No
Overexposure of a member of the public? No
Overexposure of a worker? Yes

Contamination spread within the facility? No
Damage to radiological barriers (incl. fuel damage) within the facility? No

Degradation of Defence In-Depth No

Person injured physically or casualty? No
Is there a continuing problem? No

Patricia Milligan
Nuclear Regulatory Commission (NRC)

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