The increased urgency of dealing with mitigation of the looming climate change has sparked renewed interest in the nuclear energy option. There exists a substantial stream of research on the amount of embodied energy and greenhouse gas emissions associated with nuclear generated electricity. While conventional fossil fuelled power plants cause emissions almost exclusively from the plant site, the majority of greenhouse gas emissions in the nuclear fuel cycle are caused in processing stages upstream and downstream from the plant. This paper distils the findings from a comprehensive literature review of energy and greenhouse gas emissions in the nuclear fuel cycle and determines some of the causes for the widely varying results. The most popular reactor types, LWR and HWR, need between 0.1 and 0.3 kWh(th), and on average about 0.2 kWh(th) for every kWh ofw electricity generated. These energy intensities translate into greenhouse gas intensities for LWR and HWR of between 10 and 130 9 CO2-e/kWh(el), with an average of 65 g CO2-e/kW(el). While these greenhouse gases are expectedly lower than those of fossil technologies (typically 600-1200 g CO2-e/kWh(el)), they are higher than reported figures for wind turbines and hydroelectricity (around 15-25 9 C02-e/kWh,l) and in the order of, or slightly lower than, solar photovoltaic or solar thermal power (around 90 9 CO2-e/kWh,l). (c) 2008 Elsevier Ltd. All rights reserved.