Worker Overexposure

Print View Posted on: 31 July 2018

Event Date: 06 May 2015 Event Type: Radiation Source
Event Location: United States of America, Overland Park, Kansas / DBI, INC. INES Rating: 2 (Final)

On 5/6/2015, a worker received an extremity overexposure while conducting radiographic operations at an industrial facility. A radio communication that occurred while the radiographer was relocating the collimator was misunderstood by the radiographer assistant as direction to crank out the 2.59 TBq (70 Ci) Ir-192 source. When the radiographer felt the vibration of the source being cranked out, he dropped the collimator, exited the area, and retracted the source into the exposure device. Upon badge processing results and worst case scenario calculations, it was determined that the radiographer received an extremity exposure of between 500 and 1,000 mSv (50 and 100 rem). The licensee monitored the radiographer´s hands until 6/20/2015. No signs of radiation exposure were observed. The radiographer´s year-to-date annual dose was 2.62 mSv (262 mrem). The root cause was determined to be communication weakness. Employees were informed of the incident and reminded of the importance of a visual confirmation prior to exposing the source, which has been implemented into the licensee’s protocol. The dose received is or exceeds the U.S. statutory limit for extremity dose of 500 mSv (50 rem). NRC EN53510

INES Rating: 2 - Incident (Final) as per 25 July 2018
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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