On such an exceptional job site than Chernobyl, procedures or materials, or logistics are matchless and uncommon. That unique project involves the design and construction of a huge arch-shaped structure that will encase the actual sarcophagus built after the accident in 1986. Standing on two concrete beams, that steel shield will be assembled to the west side of the damaged reactor and will be slid over the existing building. The prime aim of that project consists to:
- contain the radioactive material and to prevent any further radiation;
- to protect on-site workers during the deconstruction of Unit 4;
- to shield the actual sarcophagus against weather damage.
That new confinement shelter will be equipped with devices and facilities that will allow future dismantling of the reactor. The operation will be executed in a safe and flexible environment and human action will be limited.
The arch-shaped confinement shelter consists of a 55 millions pounds metal structure, 355 ft high, 530 feet long, and a 845 feet span. Such a structure can cover the Stade de France and the Statue of Liberty.
Under the dome, the structure will be equipped with a system of pulleys and hoists that will be used to remove and move pieces of the existing sarcophagus and of the reactor building.
Bridge cranes will be fixed at the beginning of the construction phase, before the erection of the structure to 335 feet of height. At that point, one question emerged: how to lift and install at 100 feet high few metallic pieces of 13 feet long, 7 feet high, 2 feet 4 inches wide and a weight of 12 125 pounds?
Following Vinci request, Fraco designed an innovative and non-standard platform. Frederic Maslonka, special projects manager at Fraco: “after more than a year of work and correspondance with Vinci, because requirements were constantly evolving with the complexity of the project, we were able to propose a solution to take these loads of 12 000 pounds up at 100 feet high without any anchor to the ground or to any other fixed structure. Also, the platform was equipped with wheels which allowed a movement without stopping the installation of the metal pieces. For the special purposes of that project, Fraco designed and fabricated a 49 feet long by 8 feet large freestanding work platform without anchors and mounted on motorized chassis on wheels.”
With that unique platform, parts and pieces of each of 1,6 millions pounds bridge cranes, aligned on a total length of 330 feet, will be installed. These hoists will be essential during the deconstruction phase of the sarcophagus and the damaged reactor.
As mentioned, total tare weight of the arc-shaped metal structure will be 55 millions pounds, which represents twice the weight of the Eiffel Tower. Once loaded with lifting and handling equipment, that weight will be 68 millions pounds. Life expectancy of that new confinement shelter is 100 years. The building should resist to temperatures comprised between -45 F and 113 F, to a Class 3 tornado (once every 10 000 years), and to a high magnitude earthquake.