The bare tubesheet hole is closed using a welded plug while the opposite tube end is typically mechanically plugged. The process is engineered to avoid damage to the steam generator and sample. Westinghouse has qualified the welding process specification and the welding machine operators in accordance with section IX and XI of the ASME Boiler and Pressure Vessel Code. Westinghouse performs tube removal by either robotic or manual methods, depending on the scope selected and other services being performed. All crew members receive training prior to conducting the removal services.
Qualified instructors conduct hands-on training in a steam generator mockup.
Tube pulling equipment is checked to verify operational readiness including a functional check of all tooling and equipment and issuance of a quality release for the weld plugs. Upon completion, a quality assurance approval is given and the equipment is packed for shipment to the site. Robotic Tube Removal Using ROSA III Robotic tube pull utilizes the ROSA III robot combined with specialized end effectors for a zero channelhead entry tube removal. The tube is then cut at the desired elevation using an ID cutter and a fiberoptic probe is inserted to visually verify that the tube is completely severed. The puller is then operated to pull the tube out, cutting tube sections as appropriate.