True to its credo, “a generation ahead by design,” Holtec International’s manufacturing specialists continue to bring forth new ground-breaking welding and weld examination technologies. This issue of Holtec Highlights celebrates three landmark achievements that redound to their credit.
One such transformative achievement is the successful development of the roboticized hybrid laser arc welding process, which drastically reduces the quantity of heat input to the weld zone resulting in greatly diminished base metal distortion and enhanced metallurgical/mechanical properties in comparison to conventional arc welding. This technology has been a focus of Holtec’s recent capital investments in the Company’s manufacturing plants. Its introduction to Holtec’s heavy fabrication facilities in both Camden, NJ and Pittsburgh, PA has had a palpable impact on the quality of the multi-purpose canisters and transportation casks supplied by the Company for storage and transportation of used nuclear fuel. This technology will be extensively utilized in the manufacturing of Holtec’s own SMR-160 small modular reactor components, such as the thick-walled reactors vessels, pressurizers and steam generators. The improvement in the product quality of the heavy weldments for the SMR program promises to be significant, as attested by the ongoing manufacturing of dry storage equipment.
Another notable innovation is the successful introduction of digital radiography (DR) to confirm absence of defects in the weld volume of critical welds. DR has vastly increased the sensitivity of examination capability by enabling visual access, through electronic magnification, of microstructure level images. As a collateral benefit, remote viewing and interpretation of the radiographs has become possible. Work is underway to miniaturize the DR device to make it portable so that in-service inspection of safety-related welds can occur as a routine part of in-service inspections at nuclear plants and other critical industrial installations.
A continuation of other manufacturing breakthroughs at Holtec is in the hybrid laser welding of copper. Copper, along with some other alloys, has been considered heretofore near impossible to weld with conventional arc welding techniques. Joining copper as a technical achievement, is nothing short of modern-day alchemy. This technology is scheduled to debut in the fabrication of a transport cask for our Swedish client. The high radiation shielding, thermal conductivity and ability to resist aggressive environments makes copper a great choice for disposal canisters and other nuclear applications. Thanks to our welding breakthrough, now weldments made from copper and copper alloys can be manufactured to high integrity.