A Belgian utility says an unexploded World War I shell was found on the grounds of a nuclear power plant but was safely removed by military experts.

Electrabel spokeswoman Anne-Sophie Huge said the shell was found during drainage work Wednesday in front of an administrative building outside a reactor's fenced security perimeter.

She said about 20 staff members in the office building were evacuated until a bomb squad removed the shell.

The spokeswoman could not say how close the shell was to the Tihange reactors' secured area or provide details on its size.

She said the two on-line reactors at the site, near the town of Huy southeast of Brussels, continued to operate normally.