This paper presents the results of the analytical evaluation supporting the technical justification of increasing the amount of temperbead welding, currently limited to an area of 100 in2, that can be performed on low alloy steel (LAS) nuclear power plant components. The need to expand the application area limitations is increasing for ambient temperature Gas Tungsten Arc Weld (GTAW) temperbead weld overlay repairs on LAS components. As nuclear power plants age and as inspection techniques continue to improve increasing the area limit becomes increasingly important since more indications are being identified. Existing limitations of temperbead welding area of 100 in2 imposed in the ASME Code and in Code Cases 606 and 638 for ambient temperature temper bead welding are arbitrary and overly conservative. This paper presents the analyses supporting: 1) a weld overlay repair greater than 100 in2 on a Reactor Pressure Vessel (RPV) nozzle and 2) a weld cavity repair on an RPV of 500 in2 vertical shell weld. Based on the results of these cases, conclusions regarding temperbead welding in excess of the current 100 in2 limit are made.
Machine Learning Modeling of Irradiation Embrittlement in Low Alloy Steel of Nuclear Power Plants
