Is nuclear fission a sustainable source of energy?
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Is nuclear fission a sustainable source of energy? Matthias Englert, Lindsay Krall, and Rodney C. Ewing During this century, humankind must deal with increasing demand for energy and the growing impact of burning fossil fuels. Nuclear power, which presently produces 14% of global electricity, is a low-carbon-emissions alternative. However, the sustainability of nuclear power depends on the amounts of uranium and thorium available, the economics of their recovery from ore deposits, and the safety and security of nuclear materials. Unlike combustion of hydrocarbons, which determines the amount of fuel needed for a given amount of energy, nuclear reactions can create additional fissile isotopes. Hence, the choice of nuclear fuel cycle profoundly affects the size of the nuclear resource, as well as nuclear waste management and the risk of proliferation of nuclear weapons. We argue that uranium resources, identified and yet to be discovered, could sustain increases in nuclear power generation by a factor of two or three through the end of this century, even without advanced closed-fuel-cycle technologies.
Introduction Nuclear power could ease the transition to a more sustainable energy economy, if it can substitute for enough fossil fuel. Key to evaluating the potential of nuclear energy to meet future demands are the amounts of uranium and thorium economically available. Estimates are necessarily speculative, as they require knowledge of the abundance, quality, and distribution of the metals in ore deposits, as well as the costs of extraction (mining and milling). In addition, the potential energy production is profoundly affected by the choice of nuclear fuel cycle. For the open fuel cycle, which entails direct disposal of used nuclear fuel, nuclear power capacity depends directly on the amounts of uranium and thorium available. Today’s estimates of uranium resources have identified 6300 kilotonnes (kt) (at a price of up to US$260/kg of uranium), which would sustain the current demand of roughly 63 kt/yr until the end of this century. If nuclear power generation were to double or triple by the end of the century, the currently estimated 10,400 kt of undiscovered resources would have to be brought into production as well. The open fuel cycle uses less than 1% of the energy content of the uranium fuel. In contrast, the closed fuel cycle, with reprocessing to reclaim fissile nuclides such as plutonium, can extend the uranium resource by breeding fissile 239Pu from the
much more abundant 238U or fissile 233U from 232Th. The fully closed fuel cycle requires advanced processing technologies that can efficiently separate fissile actinides, as well as the development and use of fast reactors that employ higher-energy neutrons that fission actinides more efficiently. Such fully closed systems could use as much as 70% of the energy content of the nuclear fuel. In addition to efficiency, however, the sustainability of nuclear power also depends on how each type of fuel cycle affects the risk of nuclear proliferation and the disposal of nu
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