Drop of a source into a logging well

Print View Posted on: 08 February 2019

Event Date: 21 January 2019 Event Type: Radiation Source
Event Location: Hungary, Pécs INES Rating: 1 (Final)

On the 21st of January 2019 a well-logging geophysical probe containing 239 GBq activity 241-Am-Be sealed source was dropped to the bottom of a1800 m deep well near Pecs city, Hungary. The cause of the event was the break of the probe head due to material failure. The measurements of the drilling sludge, the well and the vicinity of the wellhead showed no traces of 241-Am contamination indicated that the source remained intact. The break of the probe head was in such a place that the available emergency probe retrieving equipment (overshot assembly) and procedure could not be used immediately. The successful retrieval of the sealed source was only possible on the 06th of February 2019 using a modified retrieval technology based on the approval and oversight of the regulatory body with the involvement of a subcontractor licensed for such an activity. According to the first results of the measurements and the in-filed inspections, the sealed source was safely recovered and no indication of radioactive material release into the environment was found.

INES Rating: 1 - Anomaly (Final) as per 08 February 2019
Release beyond authorized limits? No
Overexposure of a member of the public? No
Overexposure of a worker? No

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

Degradation of Defence In-Depth Yes

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

Dr. Árpád Vincze
Hungarian Atomic Energy Authority

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