On September 08, 2015, Nuclear Regulatory Authority (ARN) was informed about a radiological incident during industrial radiography of a boiler´s manifold in the Thermoelectric Power Station, located in Río Turbio, Santa Cruz.
Two workers were exposed to a radiation field of 1.62 TBq (44 Ci) of Ir-192 while were operating a Sentinel 880 Delta equipment. The licensee and the assistant could not notice that the radioactive source was exposed while performing a set of plates. After the review of the incident details provided by the licensee, it was concluded that safety procedures were not fully observed.
According to the reading of the film badge dosimeter, the monthly whole body dose reported for worker A (authorized radiographer) was 310 mSv. Biological dosimetry performed in ARN laboratories confirmed an over exposure to ionizing radiation. Analysis of blood samples, taken 13 days after the event, gives an average whole body dose of 160 mGy. The whole body dose received by the assistant (worker B), determined through film badge reading, was 1.85mSv. In this case Biological dosimetry showed result below detection limit (< 100mSv).
As extremity dosimeters are not commonly used during radiographic operations, dose to extremities were not measured. Based on ARN dose reconstruction, it was estimated that the extremity dose received in the most exposed finger was within the [10 ;15] Gy interval.
It was concluded that the dose received by worker A exceeds the statutory annual limit of 20 mSv for whole body dose. Consequently, the radiographer (worker A) was derived to the Burns Hospital for the observation and treatment of the localized lesion and has been under follow-up until present.
The following deterministic effects were diagnosed in worker A: dry epithelitis on his left hand index finger, which evolved to moist epithelitis. Additionally, paresthesia was referred in the thumb finger of the left hand. It was observed a favorable response with early local recovery after treatment.
The event was classified as level 3 according INES scale.
Event date: Thu, 27-08-2015