[en] The Program as irradiated mechanical property test specimens of several steels in a pressure vessel wall/thermal shield mock-up facility part of a broad NRC effort to develop key neutron physics-dosimetry-metallurgy correlations for making highly accurate projections of radiation-induced embrittlement to reactor vessels. The steels studied represent a wide range of radiation embrittlement sensitivities and include plates, forgings and submerged arc weld deposits (two each). This report presents notch ductility and tensile properties information developed with specimen irradiations at simulated surveillance and in-wall locations. The irradiations were conducted at 288⁰C; neutron fluences were typical of vessel end-of-life conditions. Data comparisons are used to illustrate the toughness gradient produced by irradiation and to assess the relative irradiation effect at surveillance vs. throughwall positions. The postirradiation toughness gradient between vessel surface and midwall locations was small (31⁰C or less) for five of the six materials. Tensile test observations support the notch ductility trend indications. Simulated surveillance capsule irradiations reproduced reasonably well the embrittlement at vessel inner surface and quarter wall thickness positions in almost all cases. The primary exceptiosn to both trends were provided by the steel having the highest embrittlement sensitivity (0.23% Cu, 1.58% Ni weld deposit). Aggregate results for this material suggest an independent contribution of high (> 1%) nickel contents to radiation sensitivity development and a weld susceptibility to long term time-at-temperature effects