An explosion at a nuclear site in southern France has killed one person and injured four others, one seriously.

France's ASN nuclear safety agency says the blast Monday happened at the Centraco nuclear waste treatment center on the grounds of another nuclear site, Marcoule, near the city of Nimes. An ASN spokesman says the blast took place in a furnace used to melt radioactive waste.

Authorities say no radioactive material has leaked outside the site. Firefighters say a security perimeter has been set up around the area.

Information about the cause of the blast was not immediately available.

France is heavily dependent on nuclear energy, getting about three-quarters of its electricity from nuclear sources.

It is carrying out stress tests on its 59 nuclear reactors in the aftermath of the Fukushima nuclear disaster in Japan earlier this year.