Nuclear Welding 

Welding for nuclear power is most demanding in the primary loop, where weld quality has a direct impact on long-term system reliability. Welding of primary loop piping is one of the most critical steps in construction of nuclear power plants. As such, the primary coolant system welds are subjected to the most stringent quality standards. Liburdi Dimetrics systems are equipped with the tools necessary to achieve first time quality and mitigate weld defects.

Given the thickness of primary loop pipes, nuclear pipe welding in these applications commonly uses Narrow Gap Gas Tungsten Arc Welding (NG GTAW). Weld joint design and process parameters are important not only to initial weld quality, but also to the long-term performance of the system. Of paramount importance is the ability to minimize weld distortion and residual stresses that can contribute to degradation mechanisms such as Primary Water Stress Corrosion Cracking (PWSCC).

Liburdi Dimetrics weld heads support all three NG GTAW torch architectures: open tungsten electrode, blade and blade with rotating tungsten. There are pros and cons to each design, but if distortion and residual stress control is the primary goal, we often recommend the open tungsten electrode architecture. The open tungsten electrode enables very narrow joint designs, which translates to less weld volume, lower distortion and lower residual stresses. The blade torch designs are necessary for weld joint depths in excess of 4 inches [100mm] and require lower shield gas flows. Rotating tungsten technology adds a layer of process forgiveness and typically allows for higher metal deposition rates. At Liburdi Dimetrics we work with our customers to select the best technology for each primary loop weld design.

Nuclear pipe welding is also critical in secondary loop systems, where large bore and heavy wall piping requires repeatable weld quality and stable process control. Automated welding improves consistency and helps maintain tighter control over arc position, travel, wire feed, and heat input throughout the weld sequence. These advantages are especially important in production environments where complete welding records and repeatable results are required across a large number of similar joints.

Nuclear welding of steam generators and related heat exchanger components requires precision, repeatability, and a high degree of process stability. Depending on the application, these welds may involve tube to tubesheet, restricted access, or overlays with corrosion-resistant alloys. Liburdi Dimetrics systems provide the control needed to execute these welds with repeatable mechanical motion and stable process parameters.