The French nuclear giant Areva yesterday confirmed there was a radioactive leak from a broken pipe at a nuclear fuel plant in south-eastern France, a week after a uranium spill at another of its plants polluted the local water supply.

The latest incident comes as an embarrassment to the French government as it struggles to contain environmentalists' anger and reassure residents near its nuclear plants that they are safe.

Earlier this week the government ordered safety tests on the water table around all of France's 59 nuclear reactors. Areva is at the forefront of President Nicolas Sarkozy's quest to export French nuclear technology around the world, including to Britain. France is one of the world's biggest atomic energy nations, generating more than 80% of its electricity from nuclear power.

The newly discovered leak at a plant in Romans-sur-Isère in the Drôme region came from a damaged pipe which safety authorities said might have ruptured a number of years ago. Areva, a state-controlled firm which makes nuclear reactors and deals with uranium, said the leak came from a buried pipe transporting liquid uranium and that the crack in the tubing was "several years old".

France's nuclear safety authority, the ASN, said the leak did not reach the ground water and that there was no sign of contamination. It said initial tests showed no impact on the environment because the quantity of uranium was very small, around a few hundred grams.

Areva is also responsible for running the Tricastin power plant, in the nearby Vaucluse area, where a uranium leak occurred last week when a tank was being cleaned. Drinking well water, swimming and water sports in the area were banned, as well as irrigating crops with the potentially contaminated water. Both leaks ranked as a level-one incidents on the seven-point scale of nuclear accidents.

The ASN criticised Areva for the handling of the Tricastin leak, saying it delayed communication of the problem and its security measures were unsatisfactory. After admitting the safety lapse, Areva this week sacked the director responsible for the site and announced an internal audit.