Thermal diffusion of helium in Pu-238-doped UO2

WOS: 000331495500019UO2 samples doped with 0.1 wt.% plutonium oxide have been investigated with the aim to study alpha-damage effects and the behaviour of radiogenic helium in spent nuclear fuel by single effects studies. Characterizations were performed by X-ray diffraction, scanning and transmission electron microscopy. Helium release rate as a function of temperature and total helium quantity were measured using a Knudsen effusion mass spectrometer and a quantitative gas measurement system, respectively. A new model for the simulation of helium release has been developed taking into account single gas atom and bubble motion, trapping, grain and bubble growth. The model, embedded into commercial multiphysics software, provided a good description of the experimental data and correlations for gas-atom and bubble diffusion coefficients have been proposed. Finally, the effect of radiation damage on helium diffusion was assessed by comparing the results of the present study with literature data. (C) 2013 Elsevier B.V. All rights reserved.PELGRIMM project; Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); European Commission Joint Research Centre, Institute for Transuranium ElementsWe would like to gratefully thank B. Cremer for the SEM characterization of the samples. The authors acknowledge the support from the PELGRIMM project. Z. Talip also gratefully acknowledges The Scientific and Technological Research Council of Turkey (TUBITAK) and European Commission Joint Research Centre, Institute for Transuranium Elements for funding her grantholder contracts