Nuclear forensic signatures and structural analysis of uranyl oxalate, its products of thermal decomposition and Fe impurity dopant

Abstract

Uranyl oxalate (UO2C2O4·xH2O) may exist at the back-end of the nuclear fuel cycle (NFC) as an intermediate in spent fuel reprocessing. The conditions used in aqueous reprocessing and thermal treatment can affect the physical and chemical properties of the material. Furthermore, trace impurities, such as Fe, may incorporate into the structure of these materials. In nuclear forensics, understanding relationships between processing variables aids in determination of provenance and processing history. In this study, the thermal decomposition of UO2C2O4·3H2O and phase analysis of its thermal products are examined. Their morphologies are discussed with respect to a matrix of solution processing conditions.

Production of mixed element actinide reference particulates to support nuclear safeguards using THESEUS, an aerosol-based particulate synthetic methodology

“…This finding is consistent with Thermal Gravimetric Analysis (TGA) measurements of uranyl oxalate thermally induced oxidation, which show a uranyl oxalate decomposition (onset) temperature of approximately 350 °C. 29…”

“…This finding is consistent with Thermal Gravimetric Analysis (TGA) measurements of uranyl oxalate thermally induced oxidation, which show a uranyl oxalate decomposition (onset) temperature of approximately 350 °C. 29 Mixed element Th/U particulates were generated using the same particle synthesis conditions as the produced uranium oxide particles. Thorium nitrate was substituted for uranyl oxalate in the feedstock solution, at prescribed quantities, to obtain targeted thorium-to-uranium ratios ranging from 1 ppm Th to samples with 10% Th/U.…”