From CBC news:
"An explosion at the Marcoule plant in southern France on Monday morning has killed at least one person, according to reports.
The BBC says there is a risk of a radioactive leak after the blast at the plant in the Gard region.
One person was killed and three were injured in the explosion, which followed a fire in a storage site for radioactive waste, said Le Figaro.
Marcoule is a major site involved with the decommissioning of nuclear facilities, and operates a pressurized water reactor used to produce tritium."
Edit: Other news sources are confirming no leakage