A rail convoy carrying highly radioactive spent nuclear fuel from Italy to France set off from the northern Italian town of Saluggia overnight, Italian media reported Tuesday.

Fifteen activists -- 13 Italians, a Frenchman and a Greek -- wanted to block the train at Borgone di Susa, near Turin in northwestern Italy, but security forces persuaded them to move away from the tracks.

The spent fuel is to be treated by French nuclear giant AREVA in La Hague, northwestern France.

A French anti-nuclear group, Network Phasing out the Nuclear Age, said it was the 19th convoy since the practice began in 2007, and the first since May last year.

"More than 20 years after halting its last reactor, the use of nuclear energy in the 1980s has left Italy a heavy inheritance," it said, calling on activists to demonstrate their opposition to atomic power along the entire route of the convoy.

The treated waste will be returned to Italy in 2020 or 2025 even though the Italian government has not determined how to store it, the Network said in a statement.

"In both Italy and France, nuclear energy is at an impasse: they don't know what to do with nuclear waste," it said.

Activists came out in force to protest two shipments of nuclear waste last year.

Italians voted overwhelmingly against a return to nuclear energy in a June 2011 referendum, reflecting popular unease about atomic energy in Europe after the Fukushima disaster in Japan.