INES-event
INES 1

Unplanned exposure of workers

On 21 October , 2004 Radiation and Nuclear Safety Authority (STUK) received information that an event occurred on 20 October, 2004, resulting in unplanned exposure of two radiographers. The elevated doses, 11 mSv and 18 mSv, were caused by the failure to retract a source to its locked position after exposure. The radiographers had personal alarming rate meters, but because of using hearing protectors in noisy environment they were not able to hear the alarming sound until they had removed the device 20 meters to next workplace.

When the situation was revealed to radiographers they confined the area and notified a senior radiographer. After his arrival the source was retracted and ensured that the source is in fully shielded position. Dosemeters of the exposed workers were sent to dosimetry service for reading.

Radiographers were using Tech Ops camera model 660/664 with a 2600 TBq (70 Ci) Ir-192 source. Preliminary investigation of the device showed malfunction in locking mechanism allowing the locking of the device while the source is not totally in shielded position.

Location: Porvoo
Event date: Wed, 20-10-2004
Nuclear event report
Legenda & explanation