The speciation of niobium in the oxide layer of an irradiated Low-Tin ZIRLO nuclear material

Abstract In this study the oxidation state of niobium, within the oxide layer of a low-tin ZIRLO 1 irradiated in a nuclear reactor, is examined using synchrotron. The unique set up allows simultaneous acquisition of X-ray florescence (XRF) and X-ray diffraction (XRD) maps. A gradual oxidation and evolution of niobium is observed and quantified which is then compared with the information on the distribution of oxide phases revealed by XRD. The results are discussed with the aim to better understand the hydrogen uptake mechanism for this material, particularly the cause of the increased resistance to hydrogen uptake seen in niobium containing alloys.