On 31 August 2010 during the annual refuelling outage of the Leibstadt NPP, a diver was performing maintenance work in the fuel transfer pool within the fuel building. After completion of this work, he recovered an unidentified object and placed it into a transport basket. While the basket was lifted, before reaching the surface of the water, an alarm of the area radiation monitor was triggered. Therefore, the basket was lowered again.
As a result of the handling of the object, the diver received a hand dose of about 1,000 mSv which is twice the statutory limit of 500 mSv. The diver had worn dosimeters on different parts of the body.