Irradiation damage effects on helium migration in uranium dioxide
poster presentation: Tuesday 2010-08-24 05:00 PM - 07:00 PM in section Irradiation effects in insulators and nuclear materials
Last modified: 2010-07-05
Abstract
Helium is produced from α-decay of actinides in nuclear oxide fuels during in-reactor operation and long-term storage. Its behaviour must be understood to predict fuel element evolution in these conditions. In this study, the radiation effects on helium migration were investigated through the analysis of polycrystalline uranium dioxide samples irradiated at fluences up to 5×1015 at.cm-2 with heavy iodine ions of 8 MeV then implanted with 3He+ ions of 500 keV at 1016 at.cm-2.
Three NRA techniques of 3He detection within UO2 samples were implemented (3He(d,p)α reaction). The evolution of 3He depth profiles and the on-line helium release were first measured by NRA as a function of the annealing temperature in the DIADDHEM setup of the CNRS/CEMHTI [1]. The influence of the sample microstructure on helium migration was then studied using the microprobe of the CEA-CNRS/SIS2M. Neither helium release nor profile change are observed between 750°C and 900°C. After annealing from 1000°C, large fractions of the implanted helium begin to be released from samples. From this temperature, µNRA revealed that the gas has been preferentially released in the vicinity of grain boundaries [2].
These results can be interpreted in terms of gas precipitation and re-solution. Helium precipitation is enhanced in irradiated samples up to 900°C because of the presence of irradiation induced defects. From 1000°C, the precipitated helium is partially re-soluted [3] within the oxide matrix.
[1] G. Martin, P. Desgardin, P. Garcia, T. Sauvage, G. Carlot, M. F. Barthe, Mat. Res. Soc. Symp. Proc. 985 (2007) 0985-NN05-02.
[2] G. Martin, P. Desgardin, T. Sauvage, P. Garcia, G. Carlot, H. Khodja, M. F. Barthe, Nucl. Instr. & Meth. B 249 (2006) 509.
[3] C. Ronchi, J. P. Hiernaut, J. Nucl. Mater. 325 (2004) 11.Author(s) affiliation:
Catherine Sabathier, CEA - DEN/DEC/SESC/LLCC, Bât. 130, 13108 Saint Paul lez Durance Cedex, France,
Thierry Sauvage, CNRS/CEMHTI, 3 A rue de la Férollerie, 45071 Orléans Cedex, France,
Philippe Garcia, CEA - DEN/DEC/SESC/LLCC, Bât. 130, 13108 Saint Paul lez Durance Cedex, France,
Gaëlle Carlot, CEA - DEN/DEC/SESC/LLCC, Bât. 130, 13108 Saint Paul lez Durance Cedex, France,
Pierre Desgardin, CNRS/CEMHTI, 3 A rue de la Férollerie, 45071 Orléans Cedex, France,
Caroline Raepsaet, CEA, IRAMIS, LEEL, 91191 Gif-sur-Yvette, France,
Hicham Khodja*, CEA, IRAMIS, LEEL, 91191 Gif-sur-Yvette, France,
*presenting author