Budapest, Vienna - Faulty maintenance procedures led to an incident in the Hungarian nuclear power plant in Paks on Monday, but no radioactivity was released, a report by Hungarian authorities to the UN nuclear agency said.

It was the second incident in Paks caused by human error since 2006, the Hungarian Atomic Energy Authority said in its report to the International Atomic Energy Agency
(IAEA).

On Monday morning, two workers failed to properly seal an air- locked area during maintenance of the first unit of the power plant, 100 kilometres south of Budapest.

Although no radioactivity was released, Hungary rated the incident as 1 on the IAEA's nuclear event scale that runs from 0 to 7.

The rating, as an "anomaly" with some level of significance for plant safety, was due to the fact that the maintenance workers "serially violated" a number of rules during the incident, the report said.

This pointed to a "lack of basic knowledge", it said.

In 2006, a level-1 incident with similar causes occurred in the fourth unit of the plant. In 2003, radioactive gas was released from damaged fuel rods in a level-3 "serious incident." (dpa)