For the Ringhals 3 and 4 pressurized water reactors (PWR) reactor pressure vessels (RPV), results from the irradiation surveillance program are available also for neutron fluences, which cover long-term operation (LTO). These standard surveillance results are based on the RT_NDT concept. The belt-line welds of both RPVs have an elevated nickel-content of 1.6 wt. % and, as a consequence, irradiation response is higher than predicted by model equations. Therefore, the mechanical testing program has been expanded, exceeding the requirements of the standard testing program and covering both base and weld materials. To improve the understanding of the material behavior, extended Master Curve testing was performed on PCCV and subsize SE(B) specimens from irradiation surveillance capsules with the help of specimen reconstitution technique. Special care has been taken on the limited amount of weld material within the available broken Charpy halves before specimen reconstitution. Results have been compared to existing data on similar base and weld materials from the German research programs CARISMA and CARINA. Late-blooming effects or sudden saturation effects are not observed for base or weld materials under LTO conditions. The data for the four different weld materials of similar chemical composition indicate that not only the chemical composition, but also other influencing factors like, e.g., the welding heat treatment, may be important for the reference temperature of the unirradiated state as well as for the irradiation behavior. To investigate this effect in more detail, a future investigation program will be discussed including manufacturing of a surrogate weld material with the same chemical composition as in Ringhals 3 and 4 RPV. The influence of heat treatment condition can be investigated by applying different heat treatments and subsequently performing test reactor irradiation and mechanical testing. Specimen reconstitution will be required due to limited space inside the test reactor irradiation capsules.