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A Recent Automatic Orbital Welding Project
A major southeastern nuclear generating facility contracted with Tri Tool Thermal Services℠ (TTTS) to provide personnel and equipment for the turnkey replacement of degraded piping during a recent refueling outage.
The subject piping was part of the plant feedwater system and was targeted for replacement due to the flow accelerated corrosion (FAC) effect over several years of operation.
The scope consisted of the removal/replacement of two separate 16” spools of carbon steel piping positioned between feedwater control valves and manual gate valves. The replacement piping spools were 16” OD x .844 minimum wall thickness and a type P22 material grade.
Once mobilized, TTTS was required to complete weld testing and an exact mockup of the subject weld joint. The completed mockup (weld joint) was then subjected to multiple Non-destructive Examination (NDE) processes, including phased array ultrasonic testing.
TTTS used Tri Tool 616 RBL Clamshells to sever existing piping for removal. Once the piping was removed, a Tri Tool 214B single point end prep machine was used to produce precision J-preps for automatic welding. Weld joint alignment was within +/- .010”.
Due to the required preheat (350° F) for the replacement piping material TTTS and the utility chose to deploy Tri Tool’s new AdaptARC® automatic orbital welding system to complete the welds. The TTTS welding team utilized the AdaptARC® weld system in the GTAW mode to produce a high quality root pass, hot pass, and the subsequent fill passes for completion of the critical piping welds.
All welds were subject to several NDE processes, which again included phased array ultrasonic testing. All welds were examined before and after Post-weld Heat Treatment (PWHT) and deemed acceptable for service.
Please contact the TTTS office in Atlanta, Georgia at 800-356-3343 with any questions pertaining to this project or other inquiries as to how TTTS can assist you with a turnkey automatic welding project of this type.