Assessment of the corrosion resistance of the main alternative materials for light water reactors tolerant fuel rod cladding

Basic materials for nuclear fuel rod claddings (Zr+1%Nb and E110 alloys), as well as alternative materials for tolerant fuel rod claddings (Cr18Ni10Тi steel and 42CrNiМo alloy), that are able to maximally prevent the development of severe accidents at nuclear power plants were tested in the high-temperature water vapor environment. A comparative analysis of the corrosion resistance of these materials is presented, as well as the results of similar tests by the world’s leading scientists. Samples of 42CrNiМo alloy revealed the highest corrosion resistance at high temperatures in a water vapor environment among the alternative materials for the fuel rod cladding considered in the study. The corrosion resistance of this alloy at a temperature of 1200 °C is approximately 40 times higher than that of Cr18Ni10Тi steel and E110 alloy. The high-temperature corrosion rate of the 42CrNiМo alloy is comparable to the corrosion rate of the Fechral alloy. The hydrogen that would be released during the oxidation of the 42CrNiМo alloy claddings would be almost forty times less compared to the zirconium alloy under the conditions of severe design accidents associated with overheating of the core.