Neutron irradiation changes the mechanical properties of low alloy steel reactor pressure vessels within commercial nuclear power plants. To ensure safe operation over the lifetime of the plant, surveillance programs are implemented which are used to monitor the integrity of the reactor pressure vessel. As part of this surveillance, capsules, which contain Charpy V-notch impact specimens of reactor pressure vessel material, are periodically withdrawn from within the reactor and tested. For plants operating beyond the initial license period, additional Charpy data are needed at high neutron fluence levels to inform operation beyond 60 years. Due to limited irradiated steel, Charpy specimen reconstitution, which entails welding new end tabs onto a portion of broken Charpy specimen ends, provides an avenue to obtain this critical material property information and was recently conducted at the Westinghouse Hot Cell Laboratories. The reconstitution joining process, resulting microstructure, and corresponding properties will be presented.