Raman spectroscopic investigation of graphitization of diamond during spark plasma sintering of UO2-diamond composite nuclear fuel.

Micro-Raman spectroscopy (MRS) was utilized to investigate the graphitization of diamond particles within a UO 2 -diamond composite processed by spark plasma sintering (SPS). While pure diamond gives a sharp Raman peak at 1331.6 cm −1 , the graphitized diamond shows broad peaks either at 1350 cm −1 (G-peak) or 1580 cm −1 (D-peak). The degree of graphitization was quantified by calculating the area beneath the diamond and graphite peaks. It was found that more than 20% of diamond was graphitized on the surface of the UO 2 -diamond pellet and only around 10% diamond was graphitized in the interior regions of the pellet. This current study highlights the necessity to review the implications of these results carefully while implementing UO 2 -diamond composite nuclear fuel. [ABSTRACT FROM AUTHOR]