Six workers received a "significant" radioactive dose while trying to repair equipment at a foundry in France, safety officials revealed today.

They were taken to a hospital unit at a nuclear plant and underwent tests immediately after the incident yesterday in the town of Feurs.

Patrick Gourmelon, director for human protection at the Institute for Radioactivity Protection and Nuclear Safety said: "The data we have show that we can consider that the contamination is significant but not worrying for the health of these people.

"The level is not high enough to believe that there will be a health impact."

"If this had happened to my son, I would sleep with no problem," he said.

The six will be surveyed for the next few days to see whether the contamination flushes itself out of their bodies via their digestive tracts, he said.

The incident occurred when they were using a robot to retrieve material containing Cobalt-60 stuck in a machine used to test engineering structures.

The Nuclear Safety Authority ranked the incident as a Level 2 on an international classification scale of 7.