Measures of the environmental footprint of the front end of the nuclear fuel cycle

Abstract

EXECUTIVE SUMMARYPrevious estimates of environmental impacts associated with the front end of the nuclear fuel cycle (FEFC) have focused primarily on energy consumption and CO 2 emissions. Results have varied widely. This study revises existing empirical correlations and their underlying assumptions to fit to a more complete set of actual data. This study also addresses land transformation, water withdrawals, and occupational and public health impacts associated with the processes of the FEFC. These processes include uranium mining, milling, refining, conversion, enrichment, and fuel fabrication.To allow summing the impacts across processes, all impacts were normalized per tonne of natural uranium mined and then translated into impacts per MWh(e), a more conventional unit for measuring environmental impacts that facilitates comparison with other studies. This conversion was based on mass balances and process efficiencies associated with the current once-through LWR fuel cycle described in Appendix A.Estimates of the environmental impacts of the FEFC are summarized in Table Exec-1. Quantified impacts are limited to those resulting from activities performed within the FEFC process facilities (i.e. within the plant gates). Energy embodied in material inputs such as process chemicals and fuel cladding is identified but not explicitly quantified in this study. Inclusion of indirect energy associated with embodied energy as well as construction and decommissioning of facilities could increase the FEFC energy estimate by a factor of up to ~2. a. Includes mining, milling and refining based on current mix of mining technologies (23% open pit, 41% underground, and 36% in-situ leaching). b. Assumes DU conversion to DU 3 O 8 and shallow land burial. c. Assumes PWR fuel transported by truck a distance of 1000 km between each of the following process facilities: mining/milling, conversion, enrichment, DU disposition, fuel fabrication, and power plant. Measures of the Environmental Footprint of the Front End of the Nuclear Fuel Cycle iv August 23, 2010With the exception of water use, these impacts are very favorable relative to other competing technologies for large-scale energy production. For example, front-end processes have been estimated to account for 38% of the carbon footprint associated with production of electricity from nuclear energy (see Table 2.3). Scaling the above estimate for FEFC emissions accordingly, one estimates 7.4 kg CO 2 /MWh(e) for nuclear electricity production . For comparison, current average U.S. emissions from natural gas and coalfired electricity production are 410 and 979 kg CO 2 /MWh(e), respectively.The estimates given in the foregoing table depend upon a number of parameters that are expected to evolve with time. These include the ratio of ore to overburden and grade of the ore (i.e. % U), the mix and energy efficiency of the technologies used in the FEFC, and the rate of expansion of the nuclear industry. This study considers this time-dependency. Projections intended to bound emissions imp...

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