Innovative welding repairs of pressurizer heater nozzles save utility hundreds of critical path hours
Utilities want vendors to invest in processes and tooling that save time and dose. That’s why AREVA has developed and delivered innovative Mini-ID Temper Bead (IDTB) Welding. Focused on safety, quality, performance and delivery, AREVA recently completed extensive pressurizer nozzle repairs at a U.S. plant. The project finished 21 hours ahead of the baseline schedule and at 87% of the projected dose estimate. AREVA’s mini-IDTB reduced the weld time to install a new nozzle from 18 to four hours per penetration. In fact, the team performed repairs at 119 locations, working two locations in parallel, saving a total of 583 critical path hours as compared to the conventional repair technology. As much as a 97% decrease in weld volumes helped reduce overall project risk and schedule. The mini-IDTB approach also met personnel exposure targets for this plant, and resulted in NO safety incidents.
The processes and tooling developed at AREVA have been through extensive testing and scrutiny in an environment that emphasizes continuous learning and operational excellence. Nearly 60 U.S. plants have the potential for Primary Water Stress Corrosion Cracking (PWSCC) o n their Reactor Vessel (RV) Bottom Mounted Nozzles (BMNs). Mini-IDTB can address this challenge as well, eliminating all Alloy 600 from service while providing a permanent solution for BMN integrity.