Nuclear forensic signatures of studtite and α-UO3 from a matrix of solution processing parameters

At the back-end of the nuclear fuel cycle, spent nuclear fuel (SNF) may be processed in solution to form a precipitate of uranyl peroxide tetrahydrate, also known as studtite ([(UO2)(O-2)(H2O)(2)]center dot 2H(2)O). The physical and chemical properties of studtite are influenced by the solution processing conditions employed, thus, the processing history of the precipitate may be elucidated from these characteristics. This is useful in the field of nuclear forensics, where the provenance of intercepted illicit nuclear material is of interest. Studtite is often calcined to >= 500 degrees C to form alpha uranium trioxide (alpha-UO3), an oxide prevalent in waste storage. In this study, the crystal structure of UO3 is analysed, with a discussion on the alpha/alpha'-UO3 C2mm symmetry. The morphological and structural signatures of both studtite and UO3 are investigated, with respect to a matrix of solution processing conditions and the thermal treatment of studtite. Crown Copyright (C) 2020 Published by Elsevier B.V. All rights reserved.

Automated summary

This study focuses on the physical and chemical properties of studtite, a precipitate formed during the processing of spent nuclear fuel in solution, and its transformation into alpha uranium trioxide. The crystal structure and symmetry of UO3 are analyzed, along with the morphological and structural signatures of both studtite and UO3 under different processing conditions.