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

A new technology is emerging 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, fluid suspension, solid urethane tire, axle assemblies allow the heavy load transporters to operate in severely confined spaces on virtually ANY kind of floor surfaces.

Wheelift transporters were developed for heavy load in-plant assembly of mining trucks, transformers, steam turbines, generators, and other heavy load applications where weights exceed 80 tons and must operate on deteriorated and other “As Is” floor surfaces. 

To function effectively in ISFSI applications, the Wheelift SPMT type transporters have been designed with four more axle assemblies than would normally be required, and the stated capacity derated to only 150-tons rather than 240 tons for a typical 12-axle transporter.  This is done specifically for the purpose of getting the wheel loading low enough to carry that tonnage on asphalt roads found in and around nuclear plants. The added axles and wider faced tires assure that a 150-ton payload can be carried with the reduced likelihood of creating ruts in the road surfaces or of overloading utility trenches running under the roadways. The geometry and equalizing suspension of these transporters assure that the tires and operating surfaces are never seeing more than their design load.

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, while still having unrestricted clearance to effortlessly align the NUHOMS casks with the HSM. 

Along with greatly improved safety, effortless precision alignment is also one of the major benefits of this new system. During alignment, smooth functioning, all-directional corrections of less than +/- 1/32nd of an inch are the norm. Each on-center rotation 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 across all axle assemblies.  By independently 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 wheel motors.

An onboard diesel-driven generator supplies the transporter’s AC 480V, 3Ph electric power.  This on-board power also serves the transfer cask ram’s built-in 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.

There is much more that could be told beyond the scope of what can be accomplished here.  If you have, or are considering, the installation of one of these NUHOMS type horizontal storage module installations in your ISFSI, please contact us for more information.