U and Pu L iii XAFS of Pu-doped glass and ceramic waste forms

Abstract

X-Ray Absorption Fine Structure (XAFS) spectroscopic studies were performed on a suite of compositionally identical Pu-doped simulated waste glasses prepared 15 years ago at different α-activities by varying the 239Pu/ 238Pu isotopic ratio. The resulting α-activities range from 1.9×10 7 to 4.2×10 9 Bq g −1. These samples have a current, accumulated dose that ranges from 8.8×10 15 to 1.9×10 18 α-decays g −1. A second suite of polycrystalline zircon samples that were synthesized 16 years ago with 10.0 wt.% Pu was also investigated. The 239Pu/ 238Pu isotopic ratio in these samples resulted in α-activities of 2.5×10 8 and 5.6×10 10 Bq g −1 and an accumulated dose of 1.2×10 17 and 2.8×10 19 α-decays g −1. For both the glass and ceramic waste forms, initial analysis of Extended X-Ray Absorption Fine Structure (EXAFS) and X-Ray Absorption Near Edge Structure (XANES) indicate that the local environment around the actinides exhibit different degrees of disorder as a result of the accumulated α-decay dose.