Size effects on tensile properties of Chinese reactor pressure vessel steels and its semi-empirical normalization

As one of major barriers of nuclear reactors, reactor pressure vessels (RPVs) are subjected to neutron irradiation and faced with degradation during operation, therefore their mechanical properties are vital to the safety evaluation of nuclear power plants. Due to the radioactivity of specimens and limited space in the reactors, small tensile specimens are expected to be utilized for tensile property evaluation of RPV steels. However, the size effect would influence the tested tensile results and precise evaluation of mechanical properties of materials. This research is aimed to study the size effects of Chinese RPV steels in detail. It is found that size parameters of tensile specimen will affect the yield behavior, fracture behavior, tensile strength and the elongation, which causes are discussed as well. Moreover, a semi-empirical normalization model is built to normalize the total elongation after fracture of small specimens to the standard industrial specimens, which could make contributes to the normalization of results from different size specimens and serve for the design of small specimen of Chinese RPV steels in industry. (c) 2023 Elsevier B.V. All rights reserved.