Mammoet has finished skidding the new safe confinement arch – the largest land-based movable structure in the world – over the reactor building of the Chernobyl nuclear power plant in Ukraine.
Netherlands-based Mammoet moved the arch at the request of Novarka – the joint venture responsible for the arch’s construction – from its construction site to the reactor building using a specially designed skidding system.
The system is controlled remotely and consists of 116 skid shoes with an average capacity of 700 tonnes each. The skid shoes were synchronised on both sides of the structure to ensure a smooth and even operation. The tracks of this system were installed in a 33 degree angle to optimise the load transfer onto the foundations.
The safe confinement replaces an old shelter that was installed as an emergency measure to contain the radioactive materials in the destroyed unit shortly after the disaster in 1986. It provides a controlled and weatherproof environment where the solid radioactive remains of the destroyed unit can be held for the next 100 years.
At 165 metres long, 260 m wide and 110 m tall, the arch could house the Statue of Liberty, or the Notre Dame Cathedral. With a weight of approximately 36,200 tonnes, the shelter is about three times as heavy as the Eiffel Tower.
Mammoet also conducted all the jack-up and skidding operations during construction of the arch. The arch was built in two parts at a ‘special erection area’ – a decontaminated area at safe distance from the reactor. Each half of the arch was elevated during three jack-up operations, allowing crews to work at lower heights, increasing cost-effectiveness and improving operational safety.
After construction of the first half was finished, it was skidded into a special parking area, clearing the area for the construction of the second half of the arch. Upon completion of the second half, the two parts were connected by skidding the first part towards the second part.
The arch was built by contractor Novarka, a joint venture between Vinci Construction Grand Projets and Bouygues Travaux Publics.
You can watch a video of the safe confinement sarcophagus being moved into position at http://www.novarka.com/en/