Life-cycle impacts from novel thorium–uranium-fuelled nuclear energy systems

Abstract

a b s t r a c tElectricity generated from nuclear power plants is generally associated with low emissions per kWh generated, an aspect that feeds into the wider debate surrounding nuclear power. This paper seeks to investigate how life-cycle emissions would be affected by including thorium in the nuclear fuel cycle, and in particular its inclusion in technologies that could prospectively operate open Th-U-based nuclear fuel cycles. Three potential Th-U-based systems operating with open nuclear fuel cycles are considered: AREVA's European Pressurised Reactor; India's Advanced Heavy Water Reactor; and General Atomics' Gas-Turbine Modular Helium Reactor. These technologies are compared to a reference U-fuelled European Pressurised Reactor. A life-cycle analysis is performed that considers the construction, operation, and decommissioning of each of the reactor technologies and all of the other associated facilities in the open nuclear fuel cycle. This includes the development of life-cycle analysis models to describe the extraction of thorium from monazitic beach sands and for the production of heavy water. The results of the life-cycle impact analysis highlight that the reference U-fuelled system has the lowest overall emissions per kWh generated, predominantly due to having the second-lowest uranium ore requirement per kWh generated. The results highlight that the requirement for mined or recovered uranium (and thorium) ore is the greatest overall contributor to emissions, with the possible exception of nuclear energy systems that require heavy water. In terms of like-for-like comparison of mining and recovery techniques, thorium from monazitic beach sands has lower overall emissions than uranium that is either conventionally mined or recovered from in-situ leaching. Although monazitic beach sands (and equivalent placer deposits) only form 30% of the overall known thorium ore deposits, it is expected that such deposits would generally be utilised first if thorium becomes a viable nuclear fuel. Overall, for these four nuclear energy technologies, the range of CO 2 (eq) emissions per kWh generated (6.60-13.2 gCO 2 (eq)/kWh) appears to be low in comparison to the majority of electricity-generating technologies.

Technology Assessment of Near-Term Open-Cycle Thorium-Fuelled Nuclear Energy Systems

“…Life-cycle environmental emissions associated with thorium production and use in open Th-U-based nuclear fuel cycles were also investigated [4]. A comparative life-cycle analysis (LCA) was performed for the three Th-U based systems using GaBi4 and the EcoInvent database [4]. The LCA considered the construction, operation, and decommissioning of each of the reactor systems including all of the associated facilities of an open fuel cycle.…”

“…Further details on this methodology, the underlying data used in this analysis, and all life-cycle impact analysis results are detailed in Ref. [4].…”

“…The work centred on assessing various performance indicators spanning material flows, waste composition, economics, emissions, and proliferation resistance. These performance indicators were determined by using the UK National Nuclear Laboratory's fuel cycle modelling code ORION [2,3] and also the life-cycle analysis code GaBi [4]. In addition, background issues surrounding the proliferation resistance of Th-U-based fuels were presented at the UK PONI 2012 Conference [5].…”

“…The purpose of the paper is to provide a summary of the project. To serve this end the paper refers to some example results from component studies [3,4], and stresses the over-arching project conclusions.…”

Prospective Analysis of Life-Cycle Indicators through Endogenous Integration into a National Power Generation Model

“…Then, Data acquisition is required to quantify the input and output flows associated with the power generation technologies listed in Table 1. Inventory data for the new technologies, i.e., those potentially participating in the electricity production mix according to the optimisation of each scenario, are based on specific literature: coal thermal power plants with/without capture [37][38][39], NGCC with/without capture [40,41], nuclear fission (III and IV generation) [42,43], nuclear fusion [44], cogeneration [45], hydropower dam and run-of-river plants [46], wind farms [47,48], tidal power [49], wave power [50], photovoltaics (open-ground and rooftop systems) [51], concentrated solar power plant with/without storage [52,53], geothermal (binary cycle) power plants [54], bioresource technology (biomass integrated gasification combined cycle, biogas and waste-to-energy plants) [55][56][57], PEMFC [58], and SOFC [59]. Finally, data for both existing technologies and background processes are retrieved from the ecoinvent database [60].…”