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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Critical metals in high-growth technologies : A scenario study of equitable technology distribution in 2050

Hjortsberg, Sofie January 2016 (has links)
This scenario study focused on potential future demand of critical metals if the world strives for equitable use of technologies in the world in 2050. Smartphones and other electronics are increasing in the world and the consumption rate is high as the use-life generally are short. Technologies moving away from fossil fuels have increased in recent years and include solar cells and wind power in the energy sector and electric vehicles in the transportation sector. All these growing technologies are dependent on some specific metals. In some technological areas, the potential future use of specific metals have the risk to become critically scarce, as the use of these technologies increase. These technologies and their use of these potentially critical metals have been investigated in this scenario study, assuming equitable technology distribution in 2050. For metals which in the scenario study indicate critical supply, potential strategies have been screened. Rare earth elements have played a huge role improving wind turbines due to their use of neodymium, praseodymium, dysprosium and terbium. Indium and tellurium are used to produce the new generation of solar cells. Lithium is important in electric vehicles and smartphone batteries. These potentially scarce metals might have the possibility to be substituted with other metals that can serve as a good enough substitution in these application. If these metals are substituted it is important that the substitution materials will not in themselves become critical. Substituting one critical metal with another might just result in the same unsustainable problems. These potentially scarce metals are also connected to some environmental consequences as demand is rapidly growing and mining is the main source for these metals. Another problem is that recycling rates are low and these metals often end up in landfills where they pose a risk of leaching hazardous or harmful substances. This scenario study showed supply limitations for the seven metals that were included. The outcome of this study resulted in the following conclusions:  Indium and tellurium have a risk to become extremely critical where neither reduced material intensity nor recycling can decrease demand enough.  Lithium demand Risks to become too high to support with current reserves and as material intensity is likely to increase, and recycling only can contribute with small shares in 2050, substitution is the preferable solution to the lithium scarcity.  Neodymium, praseodymium, dysprosium and terbium demands can be reduced through reduced material intensity, but as they are dependent on other REEs the availability of these four metals will depend on the demand for other REEs  Materials under development as substitutions have to be studied regarding their availability and price sensitivity. Substituting one critical metal with another may result in similar problems for a new metal instead of a long-term solution. / <p>2017-05-02</p>
2

Impact of separation capacity on transition to advanced fuel cycles

Adeniyi, Abiodun I. 27 March 2013 (has links)
One of the proposed solutions to the issue of nuclear waste volume is to transition from once through nuclear fuel cycle to advanced fuel cycles with used fuel recycling option. In any advanced fuel cycles with recycling options, the type and amount of separation technology deployed play a crucial role in the overall performance of the fuel cycle. In this work, a scenario study involving two advanced fuel cycles in addition to the once through fuel cycle were evaluated using VISION nuclear fuel cycle simulation code. The advanced fuel cycles were setup to transition completely to full recycling without any light water reactor by assuming all LWR currently in operation will have 20 years of operating life extension and no new LWR will be constructed thereafter. Several different separation capacities (1kT/yr, 2kT/yr and 4 kT/yr) were deployed and the overall impact of these capacities was analyzed in terms of resources utilization, used fuel and waste material generated and the amount of storage space required. Economic parameter (LCOE, LFCC, etc) analysis was also performed using VISION.ECON. Results presented in this work suggest that the need for LWR-UNF storage can be minimized if sufficient separation capacity is deployed early in the fuel cycle. It can also be concluded that a FuRe system without LEU will not be feasible, thus SFRs must be designed for optional use of LEU fuel. Otherwise LWRs must continue to be part of the mix to keep the near term cost of generating electricity competitive. It was observed that the higher amount of separation capacity deployed in the advanced fuel cycles led to higher LFCC and LCOE, but also translates into less environmental impact on both front and back end of the fuel cycle.

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