Workers in part of the Sellafield nuclear reprocessing plant in Cumbria were evacuated during a radiation leak.

About 20 workers at the plant's B205 reprocessing complex were involved in the evacuation.

British Nuclear Fuels Limited (BNFL), which owns the Sellafield site, said the alarm was raised by air monitors.

BNFL said the incident, which happened during maintenance, was not regarded as a major event.

'Workers returned'

Staff were forced to leave the building when air monitors sounded the alarm after picking up the escape of radiation.

A BNFL spokesman said an initial investigation showed there was no abnormal exposure to any of the workers and no escape of radioactivity into the atmosphere.

The spokesman said: "The cause of the release was swiftly identified and stopped.

"Workers were able to return to the building after a short time and normal operations resumed."

Sensitive data

The Irish Government is currently locked in a legal battle with the UK in an effort to gain access to information about Sellafield.

BNFL has refused to reveal any information because it said it is too sensitive.

The UK Government has said the plant meets the highest international safety standards.

A spokesman said: "The very small amount of information being held back is commercial information."

Ireland is seeking full disclosure of two key reports commissioned by the British Government on economic and environmental aspects of the Cumbrian nuclear plant.