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"The beginning of the 21st century marks a critical time for nuclear energy, arguably one of the defining technologies of the 20th century," the authors write. The first commercial nuclear energy plant was built in Shippingport, PA, at the end of 1957, and today there are currently 438 nuclear power plants operating worldwide, 103 in the US. Nuclear energy provides 20% of US electricity and roughly 17% worldwide. This development was largely driven by increasing demand for energy as well as the price spikes and volatility of energy costs in the 1970s and early 1980s.
Historically, US plants have cost more to build, with longer construction times and lower capacity factors (plants were generating electricity at less than 70% of their total capacity). However, while no new plants have been ordered in the US, the subcommittee found that the economic outlook for nuclear power has improved dramatically. Capacity factors are now close to 90%, plants are being assessed at dramatically higher values than in the past, and the Nuclear Regulatory Commission expects three-quarters of operating plants to apply for license extension, providing an additional 20 years of operation. Furthermore, recent attention to the environmental effects of fossil fuel use - including global warming and local air quality - has rekindled interest in the prospects for expanding the nuclear industry.
The majority of the subcommittee's report focused on safety concerns, which have been a major criticism of nuclear power, and on some of the new designs for reactors that are being developed to address those concerns. "The most important aspects of preventing harm from the radioactivity are the functions of reactivity control and heat removal," the report states. "If both of these can be accomplished in an accident, then the radioactivity within the reactor can be contained; if they cannot, it will not be." Thus, for a reactor to be deemed acceptably safe, it must be possible to shut down the nuclear chain reaction and maintain it in a shutdown condition, and also to remove the thermal energy in the reactor to a safe heat sink.
Different reactor designs accomplish these vital safety functions in different ways. Several new advanced light water reactor (ALWR) designs have been developed over the last decade, all of which are based on the technology used in the pressurized light water reactor (PWR) and boiling water reactor (BWR) commercial power plants in operation today. These new designs incorporate many improvements over existing plants in safety, reliability and operability. For example, new safety features have reduced the probability of a core damaging accident by a factor of ten or more. Designs have been simplified, leading to capital cost reduction and streamlined operation. And the cost of electricity generated from these plants has been improved, about 20% lower than today's nuclear plants.
Waste remains a troubling problem, since spent fuel contains highly radioactive materials and must be carefully shielded for several centuries. Currently, spent fuel is stored at the reactor site, and the Department of Energy is decades behind the legislated schedule for developing a geologic repository. And despite the improved economics, "the capital cost is still too high to be competitive with gas-fired plants in the US rate deregulated market, requiring continued efforts to bring down the capital costs," the authors conclude. In fact, "The cost of nuclear power plants has been perhaps the dominant reason nuclear power stopped growing in the US." The terrorist attacks of September 11,2001, have heightened the levels of security around operating plants, and additional security requirements may be imposed, increasing operating costs.
The Department of Energy's Generation IV Initiative is focused on developing one or more next-generation nuclear energy system that can be commercially deployed no later than 2030, offering significant advances in sustainability, safety and reliability, as well as economics. International partnerships will be a vital component of the development process. However, the report concludes, "It remains an open question whether the advances in nuclear power achieved over the last decade can be utilized to develop a nuclear fuel cycle that meets the proliferation concerns and provides the obvious safety and economic advantages needed to develop support in the industry, among investors, and in the general public."
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