Structure and Phase Composition of Zirconium Fuel Claddings in Initial State and after Creep Tests

E-110 (Zr-1%Nb) zirconium alloy is used in nuclear reactors as fuel cladding material. The tightness of the fuel claddings during operation, and also during the long-term "dry storage"  depends on the stability of E-110 alloy phase composition and properties [1–3]. Phase composition of Zr-based alloys is well studied [4–8], while the studies of structural evolution in Zr-1%Nb alloy under high temperature annealing and acting stresses during the creep process, as well as its influence on the processes resulting in fuel cladding integrity violation is an urgent task.