Uranium minerals and their relevance to long term storage of nuclear fuels

The storage of spent nuclear fuels for long periods of time in geological repositories is one proposed solution to the stewardship of legacy, current and future nuclear waste. Recent studies have shown that UO2, the major component of spent nuclear fuel, can oxidise under repository conditions to a number of secondary phases. The weathering of naturally occurring uranium minerals can give an insight into the behaviour of SNF and this review highlights the structural and spectroscopic characterisation of a number of relevant minerals. Conversely, reducing conditions could also be possible and these phase alterations are also discussed. Furthermore, the interaction of these minerals with the common fission products caesium, strontium, technetium, iodine, selenium and the transuranic elements (Np, Pu, Am, Cm) is reviewed, as these minerals may provide a mechanism for the retardation of the mobility of these radioisotopes. (C) 2013 Elsevier B.V. All rights reserved.