Effect of Hydrogen Content for Mechanical Properties of ZIRLOTM tubes

In order to analyze effect of hydrogen content of Zr-Nb alloy tubes, the present study was performed tensile tests using hydrogen charged ZIRLOTM tubes at room temperature. Based on the results, the following conclusions were below; Tensile properties of hydrogen charged samples from 100 to 500ppm hydrogen contents were similar to As-fabricated specimen. And the yield stress and ultimate tensile stress of samples were slightly decreased with increasing hydrogen contents over 500ppms. In terms of integrity, there is a ductile-brittle transition when the hydrogen concentration is higher than a certain threshold (about 700ppm) at room temperature. Zr-Nb alloys have been used in cladding materials for nuclear power plants because of low neutron absorption, good corrosion resistance and mechanical properties. But, when burn-up is increased, oxidation and hydrogen concentration in fuel cladding increase exponentially by water side corrosion. As a results of high burn-up, massive hydrogen concentration of fuel claddings cause loss of ductility such that the safety margin at normal operation and accident condition. So, understanding effects of hydrogen in Zr alloys is very important to assess the integrity of developing Zr-Nb alloys. Therefore, in order to analyze effect of hydrogen content of Zr-Nb tubes, tensile tests using hydrogen-charged Zr-Nb tubes at room temperature was performed