On September 20, 2019 CSN received a communication of a potential overexposure of a worker while performing industrial radiography of components with category 2 sources of Ir-192 in the authorized bunkers of the installation.
The August monthly dose on the personal dosimeter was 193.40 mSv, exceeding the official annual dose limit.
CSN carried out an inspection and analysis of all the information provided. As a result, it was found that an event involving the worker occurred in August 14, 2019. The worker entered the bunker and while he was manipulating the film, he noticed that the alarm on his DLD dosimeter went off and he exited the bunker immediately.
Later on, it was discovered that: i) that the 1,887 TBq (51 Ci) of activity Ir-192 source was not in a safe position, ii) the safe access interlock to the bunker provided by a fixed area surveillance device failed because it was out of order.
The medical report, a mandatory requirement, concluded that there were not clinical or analytical alterations of any kind.
The CSN has also performed dose analysis estimations resulting in a value compatible with the dose recorded on the worker personal dosimeter.
Based on the above, the CSN concludes that the dose was received by the worker of the radioactive installation and as thus it must be recorded in his dosimetry history.
Event date: Fri, 20-09-2019