Frontiers of Engineering Reports on Leading-Edge Engineering from the 2002 NAE Symposium on Frontiers of Engineering (2003) / Chapter Skim
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The Future of Nuclear Energy
The Future of Nuclear Energy
Pages 53-90
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energy needs, nuclear power was largely ignored. This has changed in the last five years, as improved performance at existing plants has shown that well run nuclear plants can be a very low-cost source of baseload electrical generation.
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Today nuclear plants provide 20 percent of U.S. electrical generation without burning fossil fuels or causing air pollution or an increase in greenhouse gases.
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Finally, before nuclear power can be deployed on a wide scale, it may be necessary to reduce the potential for proliferation from civilian nuclear fuel cycles and to find better ways of managing used nuclear fuel. NEAR-TERM PROSPECTS No new nuclear power plants have been ordered in the United States since the 1970s, and no new plants have come on line since 1996.
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The particles create a barrier to the release of fission products and can withstand maximum attainable accident temperatures. The GT-MHR has a three-year operating fuel cycle half of the fuel in the reactor core is replaced every 18 months while the reactor is shut down.
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. Because of concerns about proliferation, recycling of spent nuclear fuel was banned in the United States in April 1977; spent fuel is recycled in France, Japan, the United Kingdom, Russia, and elsewhere.
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2001. Reliant Energy HL&P's Nuclear Plant Has Lowest Fuel Costs of All Power Plants in the U.S.
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to examine prospects for new nuclear plants in the United States in the next decade. According to a recent study by NTDG, a resurgence of the nuclear industry will be influenced by many factors, including economic competitiveness; deregulation of the energy industry; regulatory efficiency; existing infrastructure; the national energy strategy; safety; management of spent fuel; public acceptance; and nonproliferation (DOE, 2001~.
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In 2000, NEI formed the industry-wide New Nuclear Power Plant Task Force to identify the market conditions and business structures necessary for the construction of new nuclear power plants in the United States. In April 2001, the task force published the Integrated Plan for New Nuclear Plants, which includes a discussion of nuclear infrastructure (NEI, 2001~.
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Recently a partnership to evaluate sites for new nuclear plants was announced, and DOE selected three utilities to participate in joint government/industry projects to pursue NRC approval for sites for new nuclear power plants. These projects, the first major elements of DOE's Nuclear Power 2010 Initiative, are intended to "remove one more barrier to seeing the nuclear option fully revived" in the United States.
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When most existing U.S. nuclear plants were built, the industry encouraged by the federal government—planned to recycle used nuclear fuel by recovering plutonium.
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REGULATORY INFRASTRUCTURE NRC is perhaps best known for regulating reactor construction and operation. The agency also regulates nuclear fuel-cycle operations, including the mining, milling, conversion, enrichment, and fabrication of fuel and waste-management facilities.
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. DOE's recently announced plans to work in partnership with industry to evaluate sites for new nuclear plants will test the early site permitting component of this regulation.
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Approximations were used to model assembly-averaged thermalhydraulic effects and axial representations, and in-core fuel management was performed by trial-and-error shuffle schemes, using manual iterations until cycle length and power peaking requirements were met. Modern design software typically uses a two-dimensional code that models a full fuel assembly and uses advanced ray tracing, collision probability, or Monte Carlo techniques.
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The nuclear industry faces the dual challenge of an aging workforce and a growing gap between its employment needs and the number of graduating students. Replacement of the aging workforce is essential for both existing plants and new facilities.
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, and the American Nuclear Society and recommended that these initiatives be maintained and strengthened (DOE, 2001~. On June 10, 2002, DOE announced the establishment of a new program, Innovations in Nuclear Infrastructure and Education, that offers several million dollars in awards to university consortia to encourage investments in programs on research reactors and nuclear engineering and in strategic partnerships with national laboratories and industry.
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2001. Integrated Plan for New Nuclear Plants.
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In this paper, I summarize options for sustainable energy production, discuss the need for a significant contribution from nuclear fission and its potential for providing such a contribution, and identify some challenges that must be met to achieve that potential. OPTIONS In the following discussion of the relative merits of energy technologies hundreds of years into the future, we draw seemingly reasonable conclusions based on some fundamental truths.
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Economically recoverable oil and natural gas will probably be depleted within a century or two, and both have attractive applications besides energy production. Thus, I will not consider them as sustainable energy sources.
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Spent fuel from today's power reactors contains approximately 5 percent fission products (atoms produced by splitting another atom or by radioactive decay of another fission product) , 2 percent "fissile" material (including 235u,239Pu, and 24iPu)
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should be recycled so that as many heavy atoms as possible can fission. This will require reprocessing spent fuel, separating out the desired elements, and using reactors that can cause most of the actinides to fission.
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High-conversion reactors can be fast-spectrum reactors, and thus could be both creators of fissile material and burners of nonfissile actinides. Handling the Waste If a substantial majority of the actinides are recycled and made to fission in fast-spectrum reactors, the remaining waste will be mainly fission products.
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In summary, if a substantial majority of actinides are recycled (which will be necessary for us to tap the majority of the potential energy of uranium and thorium resources) , then the waste stream from fission power will consist of a very small volume of fission products along with a small fraction of lost actinides.
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Current U.S. policy is for all spent fuel to be shipped to a geologic repository (recently identified as Yucca Mountain, Nevada)
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are readily available and its waste stream (fission products and lost actinides) is very small and not technically difficult to handle.
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and Fast Reactors (FR) in Advanced Nuclear Fuel Cycles.
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This year, NASA announced a five-year, $1-billion program to develop nuclear reactors to power the next generation of spacecraft. History Early work on nuclear propulsion was primarily focused on nuclear-thermal technologies, in which a fission reactor is used to heat a gas and accelerate it through a nozzle.
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The specific impulse for nuclear fuels can be many times that of chemical fuels, while the thrust is correspondingly lower and the run time longer. Electrostatic thrusters have relatively low thrust but can run virtually continuously and, therefore, can provide short trip times and low launch weights for a given payload.
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Heat is produced in the nuclear source (typically a fission reactor core) and converted to electricity in the power converter.
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This device is solar powered, but future designs anticipate using a fission reactor to produce the electricity. All electric propulsion systems require supplies of electricity, and fission reactors, which have high power density, are an excellent choice for meeting this need.
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Obvious choices, such as chemical batteries, fuel cells, and fossil fuels, show some promise, but none of them can match radioisotope power for long, unattended operation (Blanchard et al., 2001~. This is because of the larger energy density available with nuclear sources.
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permits radioisotope-powered devices to last the life of the patient. Although a smoke detector is not strictly a power source, many smoke detectors contain radioisotopes (usually 1 to 5 microcuries of 24iAm)
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(b) Photograph of a device using pits rather than trenches to hold the source.
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Nevertheless, one can envision many future applications of MEMS devices with onboard micropower sources, such as small drug dispensers placed directly into the bloodstream and laboratories-on-a-chip that can carry out real-time blood assays. Researchers at UCLA and UC Berkeley have been investigating so-called "smart-dust" concepts for using wireless communications to create large-scale sensor networks (Kahn et al., 1999~.
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CONCLUSIONS Nuclear power is the best, perhaps the only, realistic power source for both long-distance space travel and long-lived, unattended operation of MEMS devices. Much more research will have to be done to optimize the currently available technologies for future applications, but nuclear technologies will clearly provide viable, economic solutions, and they should be given continued attention and support as they approach commercialization REFERENCES Allen, D.T., J
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2002. Project Orion and future prospects for nuclear propulsion.
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