DECIZA · DEscribing and Characterizing grain boundaries In Zr-Nb Alloys

Stress corrosion and macroscopic growth of cladding materials used in nuclear reactors are topics of technological interest, as the reduction in CO2 and use of green energy is one of the core objectives of the European Union. Under irradiation, material deterioration is influenced by point defects produced in large quantity and grain boundaries (GBs). In this context, investigating their interactions is of fundamental importance, which implies identifying the nature of the GBs. Therefore, in this project, the main objective will be to generate, classify and characterize GBs in zirconium alloys used as cladding tubes by resorting to relevant modelling tools at the atomic scale (molecular statics and dynamics), since this type of information is lacking for zirconium alloys and is difficult to obtain experimentally. A second goal of the project will be the specific study of the Nb alloying effect due to the technological interest of this element, through (i) the determination of its segregation energy and tendency in the vicinity of the GBs, and (ii) the influence of its GB segregation on the deformation mechanisms of zirconium alloys. Due to the expected large amount of numerical data generated mainly due to the multiplicity of the GBs investigated, a statistical analysis will be performed to assess the relevance of the descriptors used to characterize the GBs and to establish correlations with the GB properties.