PARIS (Reuters) - French nuclear firm Areva said on Tuesday 30 cubic meters of a liquid containing natural uranium was accidentally poured on the ground and into a river at a site in southeastern France.

The uranium, which was not enriched, was poured on the ground during the cleaning of a tank at the Socatri group, an Areva subsidiary, on the site of the Tricastin nuclear plant.

“Around 30 cubic meters of a liquid containing uranium, with a concentration of 12 grams of uranium per liter, was poured on the ground,” France’s nuclear safety authority said in a statement, adding that it will carry out an investigation on July 10 to determine the causes of the accident.

Socatri specializes in the maintenance and dismantling of nuclear material as well as managing nuclear waste.

Part of the liquid soaked into the ground at the company’s premises while the rest ran into the Gaffiere and Lauzon rivers, which flow into the Rhone.

A Socatri spokesman said the firm will monitor the impact of the accident on the environment.