High Borated Stainless Steel Alloys for Nuclear Reactor Domains

Austenitic stainless steel industry in the nuclear domain still needs further progress for better performance, quality and safety for being the major construction nuclear materials of different components of nuclear reactors. One grade of stainless steel with fundamental composition of SS316 and another having B (SS316B) were designed. The macroscopic cross sections for neutrons were carried out by 241Am-Be neutron source, the results confirmed that borated stainless steels fulfill the requirements of having a proper shielding material that achieves the necessary safety conditions. Samples of the modified steels were subjected to microstructure examination, hardness, impact and tensile testing. In addition, the corrosion behavior of the modified steels in 3.5 wt% NaCl medium was examined. The microstructure observation showed mainly an austenitic phase in all the modified steels. Using the scanning electron microscope in conjunction with EDX technique, a secondary phase of a different morphology and size was observed at the austenitic matrix of the other studied steel. Certainly, this change is mainly attributed to form a carbide element as boron. The investigated steel alloys containing B showed of a lower corrosion rate and higher mechanical properties than the standard alloy.