PARIS (AP) — Greenpeace activists secretly invaded a French nuclear site before dawn Monday and draped a banner on its reactor containment building, embarrassing the government and exposing the vulnerability of atomic sites in France.
Police, whom Greenpeace told immediately of the publicity stunt, took several hours to round up nine intruders who had broken into the power plant in Nogent-sur-Seine, about 95 kilometers (60 miles) southeast of Paris.
France, which gets about three-quarters of its electricity from nuclear power, regularly faces protests from environmental activists over shipments of nuclear waste. Activist incursions into atomic plants are unusual.
Greenpeace said the break-in aimed to show that an ongoing review of safety measures — ordered by French authorities after a tsunami ravaged Japan's Fukushima Dai-ichi nuclear plant earlier this year — was focused too narrowly on possible natural disasters, and not human factors.
Activists who tried to enter three other French nuclear sites in the coordinated action Monday were prevented from doing so, but Greenpeace said other invaders were still holed up inside other, unspecified, nuclear sites.
That prompted authorities to immediately launch a "thorough sweep" of all of France's 20 nuclear power plants, Interior Ministry spokesman Pierre-Henry Brandet said by phone. Interior Minister Claude Gueant has scheduled a meeting this week to launch a review of the security breach, Brandet said.
French power company Electricite de France, which operates the site, denounced the "illegal" break-in at Nogent-sur-Seine, and insisted that it did not harm security at the site.
After Greenpeace alerted authorities that its activists were behind the incursion, police and security teams held their fire and allowed the peaceful activists to continue scaling a containment building that houses the reactor to put a banner on top, Brandet said. The activists didn't penetrate the reactor.
EDF said activists' banners were also hung on the outside of two other nuclear sites — Chinon in northwestern France and Blayais in the southwest — before they were removed. Three other activists were driven off by security forces while trying to enter yet another plant, in southeastern Cadarache.
"We have to understand what's behind this malfunction — notably in Nogent," Brandet said, adding that "in the other sites security worked ... the intrusions were thwarted."
EDF said it had no indication of intrusions at other sites in France.
"With this nonviolent action, Greenpeace has shown how vulnerable French nuclear plants are," said Sophia Majnoni d'Intignano, a Greenpeace activist. "Simple activists, with peaceful intentions and of few means, were able to reach the heart of a nuclear plant."
French TV showed pictures of activists in miner's helmets rummaging through the dark and crawling in what appeared to be a tunnel with banners that read "Coucou" (Hey) and "Facile" (Easy) on them.
"The government is going to conclude in several months that our nuclear plants are very, very safe, because it's believed that they could withstand a flood or an earthquake," she told i-Tele television, referring to the upcoming government report.
"But those aren't the real risks for our nuclear industry," Majnoni d'Intignano said. "It's the risk of external, non-natural attack — like the risk of terrorism."
Speaking later by phone with The Associated Press, she urged the government to consider other risks in its review like an airplane crash, a computer virus, or chemicals explosion at a nuclear site.
"It's a very limited review; they have badly understood the signal sent from the Fukushima incident," she said. "For us, the real risks are human and technological."
Henri Guaino, a special adviser to conservative French President Nicolas Sarkozy, called the intrusion "irresponsible," but acknowledged "it still makes you think about the security of access to nuclear plants."
"So yeah, I think we'll have to learn some lessons."
Associated Press writer Sylvie Corbet contributed to this report.