Research Progress on Void Swelling and Radiation-induced Segregation of Austenitic Stainless Steel

As society's demand for energy increases, nuclear energy has become the focus of recent studies. China is strongly promoting the development of fourth generation nuclear reactor, which puts higher requirements on the performance of reactor structural materials. Austenitic stainless steel, as the core structure material, will undergo radiation damage under long-term service due to the intense radiation in the reactor core, especially the void swelling and radiation-induced segregation, which threaten the safety of the reactor operation. Void swelling and radiation-induced segregation of austenitic stainless steel are closely related to irradiation dose, irradiation temperature and alloy composition. Cold working and alloy elements are usually used to control void swelling. The 15-15Ti austenitic stainless steel shows potential for cladding of fast breeder reactor due to withstanding radiation doses over 100 dpa. However, the austenitic stainless steels developed by these two methods have not fully satisfied the requirement for service. Point defects govern the radiation damage effects; therefore, a more in-depth syste-matic and experimental analysis on the diffusion behavior of point defects is essential to understand the void swelling. Two controversial views were proposed on the mechanism of radiation-induced segregation, that is, vacancy mechanism and interstitial atomic mechanism. However, the radiation-induced segregation of austenitic stainless steel may be governed by both; subsequently, a more optimized kinetic model needs to be established for further study. In addition, recent studies show that the one dimension motion of radiation defects is related to radiation damage, but further research is essential to explore some experimental details. In the present paper, we review the influence factors of void swelling and radiation-induced segregation of austenitic stainless steel, the shortcomings of the existing controlling methods of void swelling, and the progress on the mechanism of radiation-induced segregation. Finally, we prospect the future research directions according to the existing problems of study on the anti-irradiation property of austenitic stainless steel. © 2021, Materials Review Magazine. All right reserved.