The second effect on hydrogen absorption performance of Zr-Sn-Nb zirconium alloy

Zirconium alloy has been widely used as the cladding tube of fuel element in water cooled nuclear reactor due to its low thermal neutron absorption cross section, excellent mechanical properties and excellent corrosion resistance in high temperature and high pressure steam. In the long-term operation of the reactor, in addition to the hydrogen generated by the corrosion reaction between zirconium alloy and the coolant, there are also hydrogen dissolved in water and steam, hydrogen generated by the decomposition of water under irradiation, and hydrogen added to the coolant, which will be absorbed by the zirconium alloy to some extent. On the one hand, the hydrogen absorption of zirconium alloy will accelerate the corrosion and aggravate the failure of the cladding tube. On the other hand, when the hydrogen absorbed by zirconium alloy exceeds its solid solubility, the excess hydrogen will be precipitated in the α-Zr matrix in the form of hydride. The precipitation of hydride will cause the formation of zirconium alloy embrittlement and microcrack, and damage the mechanical properties of the cladding tube. Therefore, the study of hydrogen absorption and its influence on zirconium alloys is of great significance for its safe use.