The source of the leak of non-enriched uranium was an overflow from a tank being cleaned on July 7. The reservoir collected the overflow, of which 7,925 gallons (30,000 liters) seeped into two nearby rivers and the ground.
Because of the incident local authorities prohibited using the river or groundwater for drinking and irrigation and even swimming and fishing in the rivers.
Initial findings of the French Nuclear Safety Agency said the "risk was slight". But last week the Institute for Radioprotection and Nuclear Safety, which performed tests on the extent of radioactive exposure due to the uranium leak, said it found traces of uranium in the water pre-dating the recent leak.
Uranium has been secretly kept on the facility since the 1970s, primarily nuclear waste from military stockpile, the French Atomic Energy Commission admitted on October 1998.
