New Technology - Spent Fuel Cask Transport And Alignment For NUHOMS®-type ISFSI Installations

A new technology has emerged in the nuclear industry that dramatically improves the safety and efficiency of spent fuel cask transfer to ISFSI storage facilities where the NUHOMS horizontal storage modules (HSM) are employed. (NUHOMS is the registered trademark of Transnuclear Inc and their parent company, AREVA).

This unique capability is made possible with a new type of SPMT (Self-Propelled Modular Transporter), where a large number of on-center rotation, independent fluid suspension, solid urethane tire, axle assemblies allow the heavy load transporters to operate in severely confined spaces on virtually ANY kind of operating surfaces (With due caution for asphalt at elevated temperatures).


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Wheelift® transporters were developed for heavy load in-plant assembly of mining trucks, transformers, steam and gas turbine compressors and generators, and other heavy load applications where weights exceed 50 tons and must operate on deteriorated surfaces, ramps, and cross in-floor rails.
 
The first systems were furnished to Constellation Energy and Exelon corporations for use at their Ginna and Oyster Creek nuclear generating stations. To function effectively for Constellation Energy's planned follow-on use at their Calvert Cliffs generating station's ISFSI (Independent Spent Fuel Storage Installation), the Wheelift SPMT transporters were designed with more axle assemblies and wider tires than would normally be required. This was done specifically for the purpose of getting the wheel loading low enough to carry that tonnage on the asphalt roads at the Calvert Cliffs plant. The added axles and wider faced tires assure that the 135-ton payload can be carried without grooving the road surfaces or overloading utility trenches running under the roadways. For plant application other than ISFSI-bound spent fuel, these transporters are capable of carrying up 200 tons on normal concrete surfaces. The geometry and equalizing suspension of these transporters assure that the tires and operating surfaces are never seeing more than their design loads.

With their ability to drive sideways as well as rotate on-center, or turn under full load about ANY radius, those capabilities can be used in the design of new ISFSI storage facilities that have the HSMs placed considerably closer together (easily a little as 35 feet) while still having unrestricted clearance to effortlessly align the NUHOMS® casks with the HSM.

Along with greatly improved safety, the SynchroSteer® computer's effortless precision alignment capability is also one of the major benefits of this new system. During alignment, smooth functioning, all-directional steering corrections of 1/32nd of an inch are the norm. Each on-center rotation Uniload® axle has electronically controlled precision steering and equalizing suspension, and provides ten inches of independent vertical lift. The suspension accommodates both vertical lift for self-loading and the suspension's load sharing compliance capability across all axle assemblies. By independently and electrically driving each wheel, the omni directional IP-SPMT (IN-PLANT) travel is accomplished by precisely varying the speed and direction of each axle's two precision servo wheel motors.

An onboard diesel-driven generator supplies the transporter's AC 480V, 3PH electric power. This on-board generator also provides power for the transfer cask ram's hydraulic power unit. To enhance operation during spent fuel loading and during precision alignment at the ISFSI, the engine can be shut down and a shore power extension cord plugged in for near silent operation.

Exelon's Oyster Creek nuclear station was the second plant to adopt this revolutionary new technology into their NUHOMS® spent fuel storage operations. Their ISFSI Project Lead Responsible Engineer, Mike Floyd had this to say: "The degree of added safety, fast precision alignment, and effortless movement throughout the process has totally changed our approach to spent fuel handling.". In addition to the self-propelled transporter, Wheelift designed and furnished an entirely new and improved cask support skid with an electrically actuated grapple to eliminate the industry plagued threat of a broken hydraulic line that could force dangerous recovery procedures and dosage exposure during contamination clean-up. 


In addition, the new skid is a "separate entity" design that allows the transporter to lower the transfer cask support skid onto the ground to reposition for both "road carry" and "final install" positioning, as well as the ability to drive out from under the skid to perform other heavy haul tasks around the plant, making this a highly versatile multiuse tool.

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SUMMATION: This new technology has proven itself with high marks and other nuclear plants that are using or contemplating the use of Transnuclear's horizontal storage system have been watching closely. Now that Constellation Energy has made several fuel transfers, meeting every intended goal in a manner well beyond expectations (and with NRC observers present), the responses and enthusiasm from other plants are highly positive. 

 

 

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TRADEMARKS

The following terms that are used through this website: Wheelift^®, Uniload^®, SynchroSteer^®, StackAxle^®, TrackAxle™ and OmniAxle^™ are all trademarks that are exclusively licensed to Doerfer Companies.

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"NUHOMS®" is the registered trademark of Transnuclear Division of AREVA. Wheelift Systems are not furnished or in any way endorsed by TransNuclear Inc.