Toshiba has developed Temper-bead welding by under-water laser welding to answer stress corrosion crack (SCC) for aged components of PWR and BWR nuclear power plants. Temper-bead welding by under-water technique further improves low-alloy steel toughness of Reactor vessel lager than base metal, employing proper heat input and cladding layer numbers. In this report, some evaluation results of material character by temper-bead welding to target at Reactor Coolant System (RCS) nozzle of PWR are presented.
