The E110 alloy (Zr-1Nb) designed in Russia has been in successful operation in the VVER and RBMK reactors since 1960. The evolution of the Russian reactors during this period of time, their numbers and operating parameters, and, hence, the relevant production of the cladding tubes required much effort from the researchers and producers to optimize the technological processes resulting in the high operating reliability of the fuel rods clad in the E110 alloy.

In the Zr-Nb system to which the E110 alloy pertains, highly sophisticated structure-phase transformations proceed depending on the temperature-rate conditions of processing and the impurity content of the alloy. The alloy structure formed during its processing affects substantially the processability and performance of semi-products and finished tubes. The paper demonstrates the interrelation between the structure-phase transformations of the E110 alloy and the temperature-rate conditions of processing as well as the oxygen content of the alloy. The phase composition and microstructure are shown to play an essential part in providing the tubes with the requisite properties and their stability. The properties of cladding tubes having different structures and fuel rod claddings as in-pile irradiated are analyzed. The corrosion behavior of E110 alloy claddings is shown to be strongly dependent upon the material structure and reactor operating conditions.