2007
ACLN
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G.Martin, P.Desgardin, P.Garcia, T.Sauvage, G.Carlot, M.F.Barthe, 'Helium migration mechanisms in polycrystalline uranium dioxide', Scientific Basis for Nuclear Waste Management XXX | Materials Research Society Symposium Proceedings (ed. D.Dunn, C.Poinssot, B.Begg) 985 71-76 (2007)
This study aims at identifying the release mechanisms of helium in uranium dioxide. Two sets of polycrystalline UO/sub 2/ sintered samples presenting different microstructures were implanted with /sup 3/He ions at concentrations in the region of 0.1 at.%. Changes in helium concentrations were monitored using two Nuclear Reaction Analysis (NRA) techniques based on the /sup 3/He(d, alpha )/sup 1/H reaction. /sup 3/He release is measured in-situ during sample annealing at temperatures ranging between 700 degrees C and 1000 degrees C. Accurate helium depth profiles are generated after each annealing stage. Results that provide data for further understanding helium release mechanisms are discussed. It is found that helium diffusion appears to be enhanced above 900 degrees C in the vicinity of grain boundaries possibly as a result of the presence of defects.
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