Reprocessing vs direct disposal of used nuclear fuels: The environmental impacts of future scenarios for the UK

The UK recently switched from a “nominal” twice-through cycle - whereby used nuclear fuels were reprocessed, but uranium and plutonium were not routinely reintroduced in the fuel cycle – to a once-through cycle, where used nuclear fuels are stored pending disposal. However, it is also the current strategy to keep other options open, including a twice-through cycle based on a different chemical separation process from the conventional PUREX. This article presents a comprehensive Life Cycle Assessment study of future scenarios for the back-end of the UK nuclear fuel cycle that aims at informing policy- and decision-makers. The study considers the direct disposal approach and four reprocessing scenarios envisaging different strategies for disposal and/or reuse of reprocessed uranium and plutonium, and adopts a consequential approach including only short-term effects. These primarily represent reductions in demand for uranium mining due to recycling of uranium and plutonium, and are modelled upon identification of a marginal technology. Several marginal technologies are explored because of the uncertainty regarding the actual response of the market. Results of the study show that recycling of uranium, but especially of plutonium is of paramount importance because of the avoided burdens associated with production of nuclear fuel from mined uranium. The reprocessing scenarios envisaging reprocessing of used nuclear fuels and recycling of both plutonium and uranium represent the most favourable options. The direct disposal approach may be advantageous only in terms of radiological impacts depending on the marginal technology chosen

The environmental impacts of reprocessing used nuclear fuels: A UK case study

Historically the UK implemented a “nominal” twice-through cycle whereby used nuclear fuels were reprocessed, but uranium and plutonium were not recycled: they were stored pending a future decision by the UK Government. However, the policy for managing higher activity wastes is clear: it envisages their disposal in a Geological Disposal Facility. Consultations for siting a repository - which were suspended in 2013 - have recently restarted, but the repository will not be available for several decades at the earliest. This article presents a comprehensive LCA study on the historical UK approach for managing used nuclear fuels and the UK Government policy for disposal of higher activity wastes. The underpinning purpose is to inform policy and decision-makers concerned with decisions on the future of the UK nuclear fuel cycle. The study relies on a combination of operational data from the Sellafield site – the industrial complex home to the UK reprocessing plants - and literature data on the GDF, and on a number of assumptions regarding the GDF design and disposal of higher activity wastes. The results reveal that a great proportion of the environmental impacts can be linked to two specific causes: indirect burdens from production of uranyl nitrate, which is used to separate plutonium from uranium, and copper, proposed in one scenario to be used as the outer layer of the disposal canister for High Level Waste. The results also demonstrate that the carbon intensity of the management of used nuclear fuels is practically negligible when compared with results from other LCA studies that cover the entire fuel cycle

Radiological Impacts in Life Cycle Assessment. Part I: General framework and two practical methodologies

To date, impacts of ionising radiations have been largely disregarded in Life Cycle Assessment (LCA). This omission can be linked to the lack of a standard and comprehensive framework for including the effects of radionuclides alongside other emissions from industrial processes. Drawing on a recent review of Radiological Impact Assessment methodologies for LCA studies, this article proposes an overarching framework for integrating impacts of radionuclides in the Impact Assessment phase of LCA. From this framework, two alternative methodologies have been derived. They differ mainly in the way transport and dispersion of radionuclides in the environment are modelled: UCrad represents the first-of-its-kind compartment-type methodology for radionuclides, whereas the alternative Critical Group Methodology (CGM) has been adapted from standard Risk Assessment practices. Characterisation factors for a range of emitted species have been calculated using both methodologies and compared with those obtained from the Human Health Damages methodology, which is the only approach to radiological impacts yet implemented in LCA. For both UCrad and CGM the results are in general agreement with the Human Health Damages methodology, but UCrad gives factors closer to those obtained by the CGM approach. UCrad represents a major step towards incorporating ionising radiation impacts in LCIA. A subsequent paper will explore quantitatively the main differences between the UCrad and CGM methodologies