No abstract

Substantial research has been performed in recent years to determine the effects and feasibility of welding on highly irradiated austenitic materials. This research has been driven by the need to preemptively develop welding techniques capable of repairing highly irradiated light water reactor (LWR) components susceptible to detrimental corrosion and cracking. However, the materials used to fabricate internal LWR components become increasingly difficult to weld with in-service age due to irradiation-induced generation of helium in the material matrix over time. This paper introduces a patent-pending technology that proactively manages the stresses during laser repair welding of highly irradiated reactor internals to avoid the occurrence of intergranular helium-induced cracking. The technology development relied on numerical simulations that made it possible to refine and optimize the innovative welding concept and to identify specific process conditions achieving significant reduction of tensile stress (or even formation of compressive stress) near the weld pool in the heat-affected zone on cooling. The candidate welding process conditions identified by the numerical simulations were experimentally tested on stainless steel plates (Type 304L) with a laser welding system purposely designed and engineered to incorporate the proactive stress management concept. In-situ temperature and strain measurement technique based on digital image correlation were applied to validate the numerical simulations.

No abstract

No abstract

This report summarizes recent welding activities on irradiated alloys in the advanced welding facility at the Radiochemical Engineering Development Center of Oak Ridge National Laboratory and the development of post-weld characterization capabilities and procedures that will be critical for assessing the ability of the advanced welding processes housed within the facility to make successful repairs on irradiated alloys. This facility and its capabilities were