WELDING IRRADIATED STAINLESS-STEEL

Conventional welding processes produced severe cracking in irradiated stainless steel containing 1 to 12 appm helium from (n,alpha) reaction s. A shallow penetration overlay technique was successfully demonstrat ed for welding irradiated stainless steel. The technique was applied t o irradiated 304 stainless steel that contained 10 appm helium. Surfac e cracking, present in conventional welds made on the same steel at th e same and lower helium concentrations, was eliminated. Underbead crac king was minimal compared to conventional welding methods. However, cr acking in the irradiated material was greater than in tritium charged and aged material at the same helium concentrations. The overlay techn ique provides a potential method for repair or modification of irradia ted reactor materials.