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a subcontract of the basic and detailed engineering, procurement, manufacture, factory acceptance tests, delivery, and erection of the complete main cranes system (MCS) to PaR Systems, Inc. in May 2010. BergerABAM is part of this effort to create innovative solutions for containment, cleanup, and recovery while protecting workers, the surrounding communities, and the environment from the continued high radiation levels. As a subcontractor to PaR Systems Inc., BergerABAM is responsible for the structural analyses of the MCS under operational and seismic loading. According to the design solutions, the NSC steel arch dimensions of the NSC structure are as follows. •
Maximum height - 110 meters
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Length from east to west - 164 meters
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Width from north to south - 270 meters
The main NSC bearing structure consists of 16 steel arch trusses (chords) assembled at a12.5-meter pace. The 16 steel arches are composed of a lattice structure of circular section tubes. Because of the dangerously high levels of radiation still emanating from the ruined reactor site, the NSC structure must be built away from the reactor to protect construction workers. The NSC will then be slid a distance of three football fields over the failing OS on a runway system, making the NSC the largest moveable structure in history. Hanging just below the ceiling of the NSC structure, approximately 80 meters aboveground, are two 96-meter bridge cranes supported on six runways, top running, under hung design. The bridge cranes will be remotely operated from a control room located in a building separate from the NSC structure. The remote-controlled cranes will be used to safely dismantle the OS, with workers manipulating these cranes using cameras. Telescopic crane arms normally used for remotely controlled applications could not be used because the size and length necessary to handle the very large deconstruction loads would make the cranes unstable. Instead, the cranes use three different carriages listed below. 1. A classic carriage with 50-ton hoist capacity. 2. A secure carriage with 40-ton capacity (personnel)/50-ton capacity material that may be used to transfer maintenance personnel around the facility in a shielded box. 3. A unique device called the mobile tool platform (MTP) carriage, a tensile truss structure that is mounted below a carriage. The tensile truss structure is used as a stable platform for robotic manipulators and other remotely operated tools, which help dismantle and transport the debris. The MTP design provides sufficient stiffness while still having the maneuverability needed for remote tooling. Six independent wire rope hoists achieve the long vertical reaches necessary to transport and handle the debris generated by the deconstruction of the OS. BergerABAM analyzed the seismic and operational loads these cranes would have to handle, thereby helping to create the computerized control system necessary to keep the platform’s movements well constrained. This constraint is achieved by keeping all six ropes in tension, thereby making the system behave like a rigid truss structure—ideal for operating and manipulating heavy tools. The MTP is the largest known implementation of tensile truss design, and the first of this size to be used in recovery operations. The MCS subcontractor, PaR Systems, is making significant progress in the fabrication and assembly of the various components and getting ready to commence the factory accepting testing program. The shipment of the MCS components is scheduled in March 2014.
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