The world's largest movable metal structure yesterday rumbled into place over the Chernobyl nuclear power plant's ruined fourth reactor to ensure the safety of Europeans for generations to come.

The 108 meters of the arch make it taller than New York's Statue of Liberty while its weight of 36,000 tons is three times more than the Eiffel Tower in Paris.

It was edged into place over an existing crumbling dome that the Soviets built in haste after disaster struck at the plant in Ukraine 30 years ago.

The 2.1-billion-euro (HK$17.2 billion) structure for the facility has been sponsored by the European Bank for Reconstruction and Development.

"We welcome this milestone in the process of the transformation of Chernobyl as a symbol of what we can achieve jointly with strong, determined and long-term commitment," bank president Suma Chakrabarti said. "We applaud our Ukrainian partners and the contractor and we thank all donors to the Chernobyl Shelter Fund whose contributions made [the] success possible."

The dome must now be fitted with radiation control gear, air vents and fire protection systems that are due to start working by the end of 2017.

AGENCE FRANCE-PRESSE