Hydrogen influence on zirconium alloy Zr-0.5Nb mechanical characteristics at ambient and elevated temperatures

The analysis of material aging influence on service lifetime of fuel channels (FC) tube is executed from the positions of fuel channel ability to perform predicted by the design its functions. It is well known that radiation in certain degree can have an effect on all functions and properties of fuel channel material. Radiation may cause changes in fuel channel tube sizes; in addition to this, an essential effect on the majority of functions and properties of the fuel channel tube has radiation strengthening, embrittlement and hydrogen ingress. Hydrogen ingress leads to the embrittlement and degree hydride cracking (DHC) of zirconium alloy and is one of the factors, which has an influence on fuel channeltube service lifetime. Also it is one of the consequences of corrosion, which depends on the parameters of heat-transfer agent and structural state of material. Usually the analysis of kinetic dependence of the hydrogen ingress in the zirconium alloy is examined in connection with the kinetics of oxidation, but to analyze the kinetics of oxide film is very difficult because it is washed away by coolant. During reactor operation, several factors influence FC aging including hydrogen ingress to zirconium material, embrittlement, corrosion and the related reduction of pipe wall thickness, possible crack growth by DHC mechanism when hydrides are present in the alloy.