XANES and EXAFS studies of plutonium(III, VI) sorbed on thorium oxide

R. Drot
2000 AIP Conference Proceedings  
P u F u t u r e s -T h e S c i e n c e 94 calculated EXAFS spectrum of the model solid, ThO 2 doped Pu (1%), using FEFF7 code. 4 The obtained results indicate that the plutonium is sorbed as an innersphere complex. By studying the XANES part of the X-ray absorption spectra, it is possible to identify the oxidation state of sorbed plutonium. Previous published works 5 have shown that the position of the Pu L III white line depends on the oxidation state of the plutonium species. The obtained
more » ... lts show that the plutonium is not sorbed at the same oxidation state as when it was initially introduced in solution. This seems to indicate that, in our experimental conditions, no oxidation or reduction phenomena occur in the electrical double layer. P u F u t u r e s -T h e S c i e n c e 96 Figure 2. Crosssectional brightfield TEM micrograph with associated electron diffraction pattern showing the formation of an amorphous band in a cubic zirconia sample (stabilized by 9.5 mol. % of yttria) after 70 keV Cs + implantation to 1x10 21 Cs/m 2 at room temperature. The overlay of the Cs concentration profile is based on the results of analytical TEM that has been normalized by the results of a Monte Carlo computer simulation using the SRIM code. 97 Materials Science Poster Session Various types of nanometer-scaled defect clusters (e.g., dislocation loops or small gas bubbles) were apparent in samples implanted by the other three ions after 1x10 20 ions/m 2 . However, other than Xe bubbles, no secondary phase precipitates were apparent in YSZ implanted with Xe, Sr or I ions even after 1x10 21 ions/m 2 . No amorphization was observed after 400 keV I + implantation to 1x10 21 ions/m 2 at 973 K, even though iodine has a larger ionic radius than cesium, due to the relatively high mobility of iodine in YSZ at the high temperature.
doi:10.1063/1.1292215 fatcat:hncygxbtsbcqhdavimsbr26w5q