Article published on the 2009-10-15 Latest update 2009-10-15 15:44 TU
The Authority says the plutonium was overlooked during an inventory of nuclear material at Cadarache. The Authority only announced the discovery last week, but the incident was first brought to light in June.
Ecology minister, Jean-Louis Borloo, has stressed the importance of transparency in all issues of nuclear security.
Meanwhile, Greenpeace France has described the incident as one of the most serious the country has seen at a nuclear plant for many years.
The organisation has called for the government to come clean about how much plutonium was discovered. It claims that small amounts of the material could be the equivalent to five nuclear bombs. Initial estimates say around 22 kilos were found.
The Atomic Energy commission says this figure could rise to as much as 39 kilos.
The plant at Cadarache produced MOX for nuclear reactors. It was shut down in 2003 and was in the process of being dismantled since March this year.
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