1. CEA-DEN, Dept. for Nuclear Materials, Section for Applied Metallurgy Research, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex, FR (Corresponding author), e-mail: jean-christophe.brachet@cea.fr
2. CEA-DEN, Dept. for Nuclear Materials, Section for Applied Metallurgy Research, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex, FR.
3. CEA-DEN, Dept. for Nuclear Materials, Section for Research on Irradiated Materials, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex, FR.
4. CEA-DSM, IRAMIS/SIS2M/LEEL, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex, FR.
5. Chimie Métallurgique des Terres Rares, ICMPE, CNRS, Université Paris-Est, 2-8 rue H. Dunant, F-94320 Thiais, FR.
6. AREVA-CEZUS, BP21 44560 Paimboeuf, France.