Enhancing austenitic stainless-steel alloys for fast breeder reactor fuel cladding: A comparative study

Abstract

In the present study, a series of austenitic stainless-steel alloys were developed for use as fuel cladding in fast breeder reactors. Standard austenitic stainless steel AISI316L was prepared and studied as a reference sample. Either intermetallic phases or secondary carbides were suggested to enhance the characteristic properties of austenitic stainless steel. Therefore, two samples were prepared by partially and completely replacing molybdenum with tungsten and a third sample was micro-alloyed with titanium. The characteristic properties of the three prepared alloys were compared with those of AISI316L through thermodynamic calculations that predicted the possible phases in the different alloys. Scanning electron microscopes detected the microstructure of the other alloys, and X-ray diffraction patterns of the new alloys were compared with the standard alloys. The mechanical properties of the prepared alloys were studied using Vickers hardness and tensile tests, which were conducted at room temperature to monitor the enhancement in the characteristic properties of the stainless-steel alloys. The results show that the modified austenitic stainless steel samples containing tungsten or titanium have preferable properties, such as higher hardness and yield strength. The nuclear properties of the modified stainless-steel alloys were measured using nine different gamma-ray energy lines to determine the mass attenuation coefficients (σ, cm²/g) for the alloy samples, and the results showed an excellent agreement with those calculated using the WinXcom computer program (Version 3.1). The macroscopic neutron cross-sections (Σ, cm⁻¹) for the prepared stainless-steel alloys were measured using four types of neutron energies, which were affected in the modified stainless-steel alloys.