Characterization of Nuclear Materials in Extreme Conditions: Raman Spectroscopy Approach

A review is given of our last advances on Raman spectroscopy characterization of irradiated and/or leached UO
₂
, PuO
₂
and (U,Pu)O
₂
samples. For this purpose, three original Raman setups dedicated to the study of nuclear materials were involved. In every case, irradiation-induced Raman defect bands in the 500 - 750 cm
^-1
range was observed. For UO
₂
, an annealing temperature experiment suggests that these defect bands could be the signatures of medium-range structured defects. Besides, the leaching experiments show different behavior between the irradiated in situ probed UO
₂
ceramic and post mortem probed [UO
₂
+ (U,Pu)O
₂
] sample: The growth of an altered layer made of studtite and schoepite phases was monitored at the surface of UO
₂
ceramic, while post-mortem studies reveal the presence of U
₃
O
₈
and studtite phases at the surface of the UO
₂
grains of the binary sample. No alteration layer was observed at the surface of the leached (U,Pu)O
₂
grains.