About 60 people dressed in white overalls erected yellow banners reading "Stop nuclear slavery in Russia", "No more Chernobyls" and "The atomic energy ministry grows fat, while Musliumovo dies" in a dozen different languages.

The village of Musliumovo, in the Urals region of Chelyabinsk, lies close to the site where the Mayak reprocessing plant carried out nuclear tests during the Soviet period.

The demonstrators also carried dozens of hand-held placards bearing the names of contamined villages across Russia and Ukraine with the mention: "the unknown Chernobyls."

An estimated 15,000 to 30,000 people have died in the aftermath of the April 26, 1986 explosion of Chernobyl's number four reactor, spewing radiation across much of Europe in the world's worst civilian nuclear disaster.

"Everyone knows about Chernobyl, but no one pays any attention to other places where people are dying or getting sick... These people must move, they need new jobs and new houses," said Pavel Somotkin, a student and Greenpeace activist.

"We're here to support the children who have suffered, and still suffer, from the impact of Mayak," he added.

"Mayak is no longer a real threat," a ministry spokesman said. "Musliumovo is in the same situation as neighbouring villages. This is due to disastrous social problems in the area."

On Tuesday Russian Atomic Energy Minister Alexander Rumyantsev warned that a concrete "sarcophagus" around Chernobyl's number four reactor was at risk of cracking and had to be reinforced.

The plant was finally shut down in December 2000 under a 2.3-billion-dollar deal between Ukraine and the world's richest nations.

SPACE.WIRE