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The National Academies Summit on America’s Energy Future: Summary of a Meeting 6 Nuclear Power Nuclear power accounts for 20 percent of the U.S. electricity generated and does not release greenhouse gases into the atmosphere during power generation. Yet no new nuclear plants have been ordered in the United States for more than 30 years, Ernest Moniz pointed out, and the contributions of nuclear power to the nation’s energy supply will decline unless a range of societal and economic issues are addressed. “For the short to medium term, said Moniz, the challenges “are frankly less technology and more policy and financing.” Moniz summarized the findings of a recent report on the future of nuclear power done by a group at the Massachusetts Institute of Technology (Deutch and Moniz, 2003). Three issues discussed in that report are critically important, he said: the economics of nuclear power, reprocessing and its connection to nuclear proliferation, and spent fuel management. THE ECONOMICS OF NUCLEAR POWER Like coal-fired power plants, nuclear power plants are capital intensive, Moniz observed. Furthermore, the price of large infrastructure projects has increased dramatically in the past few years—on the order of 75 percent over the past 3 years for large power plants. For that reason, although the 2003 report assigned a price to nuclear power of about $2,000 per kilowatt, current costs are substantially higher. Nevertheless, companies continue to express renewed interest in the construction of nuclear power plants. The Nuclear Regulatory Commission has
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The National Academies Summit on America’s Energy Future: Summary of a Meeting received 30 or so indications of interest from utility companies, with a number of those indications moving forward to more formal consideration. Most of these plants would be based on evolutionary improvements of existing designs with some improved safety features. Plants also could be built that incorporate advanced concepts developed through nuclear research and development programs. The MIT report (Deutch and Moniz, 2003) argued for public support for a limited number of “first mover” power plants that represent safety-enhancing evolutionary reactor design. “If we want to demonstrate what the performance of these new plants will be technically and what their construction will look like in the new regulatory environment, … we need to get out there and build some plants,” said Moniz. “You want to build a few of each design to establish the cost performance, the construction performance, and to [assess] the regulatory regime. Then it has to compete in the marketplace.” Another economic consideration involves the licensing of existing and future plants, Ray Orbach pointed out later in the summit. At a recent workshop on nuclear power, engineers in the nuclear industry were asked what their greatest problem was. Their response was, “cracks,” Orbach said. Licensing of existing plants was extended from 40 to 60 years in the past. The issues associated with extending licenses to 80 years, which would substantially reduce carbon dioxide emissions, are now being examined. “We are now trying to extend the licensing [of nuclear plants] for 20 more years,” said Orbach. But “there are real problems associated with fission energy, not the least of which are the materials issues surrounding the reactor itself.” The Department of Energy is now funding research in materials science, nuclear physics, and advanced computing designed to understand and control processes that occur during nuclear power generation. For example, Orbach mentioned the possibility of developing self-healing materials that would reduce the problems observed in current reactors. Steven Specker also emphasized that careful planning today can do much to extend the lifetimes of current and future generations of nuclear power plants. “It’s like your own health,” he said. “You better start taking care of yourself now. And we need to be doing things on today’s plants that would allow [their lifetimes] to be extended.” REPROCESSING As Orbach observed, the spent fuel that emerges from nuclear power plants still has a lot of energy left in it. By disposing of that fuel, the remaining energy is wasted. In addition, if the price of uranium increases, the energy left in spent fuel becomes even more valuable. To extract this energy, the current administration has proposed a global nuclear energy partnership that would reprocess spent fuel in specialized reac-
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The National Academies Summit on America’s Energy Future: Summary of a Meeting tors. These reprocessing technologies can reduce the amount of waste that needs to be managed and increase the amount of energy produced from a given quantity of uranium. However, Moniz and several other speakers at the summit were skeptical about the merits of reprocessing in the near-term future. First, reprocessing technology currently in use can be used in nuclear weapons. Second, Moniz and other speakers argued that the claims for the waste management benefits of reprocessing are exaggerated. John Holdren observed that reprocessing might reduce the volume of waste, but volume is not the constraint on the capacity of a waste repository. The constraint is the amount of heat generated by the waste, and that problem cannot be solved without reactors for reprocessing that are at least 40 to 50 years away. Reprocessing spent fuel makes nuclear energy “more complicated, more expensive, more proliferation prone, and more controversial,” Holdren said. “If you want nuclear energy to be rapidly expandable, and to take a bite out of the climate change problem, you want to make it as cheap as possible, as simple as possible, as proliferation-resistant as possible, and as non-controversial as possible, and that means you don’t want to reprocess any time soon.” At the same time, all of the speakers agreed that research on reprocessing for the longer term should be intensively explored. “We need to be investing in it,” Holdren said, “but what we don’t need to be doing is deploying reprocessing soon with technologies that are currently available because that will shoot nuclear energy in the foot.” Moniz pointed out that far too little has been invested in advanced nuclear concepts, and “we are paying the price today for that lack of adequate research.” For example, one possible approach would be for a balanced fuel cycle in which conventional reactors in “user” states feed spent fuel into a complex of advanced reactors located in “supplier” states (Figure 6.1). The user states would be assured of nuclear fuel supplies so long as spent fuel is returned to the supplier states. In this way, small nuclear programs could lease their fuel from states with advanced reactors, which would address proliferation concerns while concentrating and reducing the quantities of waste. THE DISPOSAL OF SPENT FUEL The management of spent fuel remains a difficult issue in the United States and around the world. Long-term geological isolation of spent fuel “appears to be scientifically sound in well-chosen sites with good project execution,” Moniz said. Yet a system to dispose of nuclear waste has not yet been implemented anywhere in the world, and whether the designated U.S. site for spent fuel, Yucca Mountain in Nevada, can be licensed remains up in the air.
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The National Academies Summit on America’s Energy Future: Summary of a Meeting FIGURE 6.1 Under a closed fuel cycle plan, user states would send spent fuel to supplier states that would reprocess the fuel to produce waste and separated uranium for additional energy production. SOURCE: Deutch and Moniz (2003). Reprinted, with permission, from Ernest Moniz and Massachusetts Institute of Technology. The MIT report concluded that storage of spent fuel for a century or so should be implemented as part of the nation’s spent fuel management system (Deutch and Moniz, 2003). Ideally, spent fuel would be stored at centralized locations under federal control. Storage allows some of the heat of the fuel to dissipate, Moniz pointed out. It also would enable the further development of technologies and policies that could influence decisions about the management of spent fuel. “There is no urgent need for us to fill Yucca Mountain,” he said. A “measured pace” is the better alternative. Interim storage in federal facilities would have the advantage of decoupling the private sector imperatives for running power plants from the longer-term and more difficult challenge of implementing and managing spent fuel disposal. However, there are political pressures to move forward to demonstrate that spent fuel can be well managed. Interim storage also would provide more time for the large amounts of research that still need to be done on the disposal of nuclear waste, given that a substantial expansion of nuclear power generation will create much larger quantities of waste. As Orbach pointed out, if nuclear power is to provide a considerable portion of the future U.S. electrical power, “we would have to have eight Yucca Mountains by the end of this century in order to store the spent fuel.”
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The National Academies Summit on America’s Energy Future: Summary of a Meeting FUSION ENERGY Orbach also discussed fusion energy, which is “incredibly energy productive,” he said. “But it takes place in the interior of stars, where the temperatures and pressures are a bit higher than those we have been able to achieve here on Earth.” Fusion reactors use isotopes of hydrogen as an energy source, including deuterium and tritium, and “there is enough deuterium in a body of water the size of Lake Erie to meet the energy needs of this earth for a thousand years,” Orbach said. Fusion produces energetic particles and radiation that need to be captured in the wall of a reactor, which produces heat that can be used to generate electricity. It has been a very difficult process to master and cannot be mastered in the short term, but “we are entering a new era with ITER,” Orbach said. ITER is an experimental fusion reactor in which hot gas is confined in a donut-shaped vessel and heated to more than 100 million degrees. The facility, which is sited in France and is a joint project of six nations and the European Union, is designed to produce about 10 times as much energy as it uses (Figure 6.2). The next step beyond ITER, Orbach said, will be a demonstration power plant based on fusion. FIGURE 6.2 The fusion reactor ITER is designed to produce 10 times as much energy as it consumes. (Note size of human figure circled at lower left.) SOURCE: U.S. ITER Project Office, Oak Ridge National Laboratory.