ADVERTORIAL FEATURE | ARC SAW TECHNOLOGIES, LLC
Arc saw segmenting of CANDU shield plugs
The arc saw is a circular, toothless saw blade that cuts any conducting metal without contacting the work piece.
It is now being used to segment Candu reactor components in Canada Authors: Thomas S. LaGuardia, PE, CCP | Richard F. Simoneau CCNuclear, LLC | Julien Moussalam, P. Eng.
Introduction Arc Saw Technologies, LLC (AST) was contracted to design, test and deliver an underwater Arc Saw to segment 21 Whole Adjuster Rods and 89 Shield plugs from the Gentilly Unit 2 (G-2) CANDU reactor at Bécancour, Quebec. After demonstration testing at AST’s shop in Connecticut, the Saw system was shipped to CCNuclear’s facility in Montreal for full scale testing and training of the G-2 operating personnel. Following fine-tuning of the system in Montreal, the Saw system was shipped to G-2 for use in its service pool.
The Lessons Learned of innovations and modifications
from that experience will pave the way for improved efficiency and safety in subsequently designed Arc Saw systems.
General Arc Saw Description The arc saw is a circular, toothless saw blade that cuts any conducting metal without contacting the work piece. Cutting is accomplished by using a high current electric arc between the blade and the work piece resulting in no reaction forces between the blade and work piece. The blade, made of any electrically conducting metal such as
stainless steel, tool steel, mild steel, or copper, rotates between 300-500 RPM removing molten metal (dross) created by the arc in the kerf of the cut. The molten metal solidifies as highly oxidized pellets expelled from the kerf. The depth of the cut (up to 26 in.) is determined by the blade diameter and the electric power delivered to the blade. (See Figure. 1).
G-2 System Design The Arc Saw system consists of two elements: 1) the Saw cutting assembly, and 2) the workpiece feed, delivery and containment system. The cutting Assembly includes the Saw Head, Commutator Brush Enclosure, Conducting Cables, Ground Clamp, Blade, Blade Drive Motor, Hydraulic Motor Hoses, and Traversing Cutting Drive Motor. The feed system for G-2 consisted of a manual chain driven V-Shaped tray to advance the Shield Plug or Bar up to the Stop Gate and into position to be cut by the Saw Blade, then clamped by the Ground Clamp. An aluminium tank with a cover was provided to contain the dross from the cut and was fitted with 150 GPM filter system designed and supplied by CCNuclear. (See Figure 2)
Right, Figure 1: Arc Saw
Far right, Figure 2: Delivery System
22 | February 2024 |
www.neimagazine.com
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