ARC SAW TECHNOLOGIES, LLC | WM SYMPOSIA, SPONSORED FEATURE
formula. Mockup specimens of 3.75-in. dia. solid stainless- steel and 3.0-in. dia. Stainless-steel tubing were cut at 3-in. per min. cleanly through without slag on the back faces.
Operational Parameters for Reliable End-User Success For this application, reliability for cutting highly radioactive components underwater was more important than cutting speed. Accordingly, AST recommended a 30-Volt DC differential, 4,000 amps DC and a cutting speed of 3-in. per min. for the Shield Plugs and 300 amps for the Comp Bars.
Arc Saw and Tank to be Packaged in a Modified B-25 Container Upon completion of all segmentation, the entire Arc Saw Assembly and Containment Tank will be placed in a modified B-25 container for disposal. The B-25 will self-drain and will be ventilation dried for disposal in a dry storage waste facility. This minimizes waste volume and potential dose to workers from otherwise decontaminating and dismantling the Arc Saw.
Demonstration Tests in AST Shop AST prepared the assembly design at our shop in Southbury, CT including all machine shop drawings. The major components includes the Saw Head and blades, Support Assembly, Ground Clamp and Containment Tank. CCNuclear provided the electric Power Supply Rectifier rated at 0-40 VDC and 4,250 Amps output per AST specifications, and the ultimate Filtration System for the end user. A temporary Test Tank was rented locally, and a temporary 40 gpm pool filter purchased for the Demonstration Testing. A 300 kW, 480 VAC, 3-Phase diesel-generator was rented for the testing program. After preliminary testing by AST and adjustments, CCNuclear witnessed the performance tests.
Rapid Blade Change Out Demonstration The AST shop demonstration included testing the design for rapid remote blade change. Saw blade change must be conducted underwater as both the blade and Arc Saw Assembly is expected to be contaminated with highly radioactive dross. The Arc Saw Frame Assembly would be removed from the Containment Tank and suspended alongside the pool walls for blade change. A davit crane with an extendable boom, and a special blade hook designed to latch on a shoulder bolt on the blade. A long-handled tool was designed with a quick-disconnect universal joint socket to unbolt the blade nut and retain it in the socket. The new blade installation is just the reverse of this process.
Final Acceptance Tests at CCNuclear AST shipped the entire Arc Saw and components to CCNuclear’s shop in Beauharnois, Canada for final demonstration testing and training of the operating crew. CCNuclear reassembled the Arc Saw system in their 10 ft x 10 ft x 4 ft deep pool and designed and fabricated a power access panel and the filtration system for the Containment Tank rated for 125 gpm. A scaffolding system was erected adjacent to the pool to simulate the 18-ft submerged distance above the Arc Saw for operations and blade change. After preliminary operational adjustments the Arc Saw
performed as designed, and the CANDU end-user Hydro- Quebec was invited to witness the Final Acceptance tests and to send their operating crew to be trained on the use of the Arc Saw System.
Segmentation Parameters Tested AST tested the following parameters as prescribed by its
proprietary design formula: ● Cutting Volts and Amps – 30 to 40 VDC, 4000 amps ● Cutting Speed – 3 to 7 in. per min. ● Blade Rotational Speed – 300 to 500 RPM ● Blade Diameter – 34 in. ● Blade Thickness – 3/16-in.
Demonstration Tests Results The initial cutting speeds were 3 linear in. per min. and were increased to 6 in. per min. which was the design speed. At 7 in. per min. the cut failed as it approached the center of the 4-inch diameter mockup, consistent with the AST design
Conclusions AST’s Demonstration Program showed the Arc Saw performed precisely as AST designed with respect to cutting speed and cleanliness of cut. Although there was some minor redesign work with respect to the Ground Clamp and HPU flow rates, and some refinement in the Shield Plug and Comp Bar Feed system to smooth out the movement, the Saw System performed well. The Shield Plug and Comp Bar mockup cuts were precise to fit into the existing spent fuel waste disposal containers. Blade changeout was successfully demonstrated at a distance during the tests. Arc Saw Technologies, LLC (AST) filed for and was granted
patents in the US and Japan and has a patent pending in Canada. ■
Left, figure 3: Shield Plug cut in half
Left, figure 4: HPU, control console and rectifier
Contact: Mr. LaGuardia at (203) 300-2958 or Mr. Simoneau at (203) 833-3902
www.neimagazine.com | February 2023 | 37
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