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| Fig. 1: Schematic diagram of a typical pressurized-water reactor. Source: Wikimedia Commons |
In the early 2000s, the suggestion of a "nuclear renaissance" emerged due to the growing demands for energy and the rising costs of oil and natural gas. Nevertheless, the support for nuclear power as an energy alternative currently remains weak due to the unfulfilled promise of stricter carbon regulations, the currently near-record low price of shale gas, and more significantly, the accident at the Fukushima Daiichi nuclear plant in Japan. [1] As of 2010, there are 104 operational nuclear power reactors in the United States, which contribute 807 TWh/yr--roughly one-fifth of the nation's total annual electricity supply. [2,3] The Nuclear Energy Institute expects only a handful of new reactors to enter service by 2020. [1] However, in February, the United States Nuclear Regulatory Commission (US NRC) granted permission for the construction and operation of two new reactors at the Alvin W. Vogtle Plant (Plant Vogtle). These reactors are the first to be built in the US in three decades, and will perhaps pave the road for a nuclear renaissance. [4]
Plant Vogtle is an $8.87 billion dollar plant operated by the Southern Company near Waynesboro, Georgia. [5] The plant currently consists of two Westinghouse reactor units, Vogtle-1 and Vogtle-2, constructed in the 1970s. [3,5] Each unit is a four-loop pressurized water reactor (PWR) configured with four steam generators, four reactor coolant pumps, a pressurizer, and 193 fuel assemblies. In a typical PWR (Fig. 1), water is heated by the reactor core before being cycled to a heat exchanger and steam generator. The produced steam flows to a combined high- and low-pressure turbine generator. The high-pressure steam flows to an electricity-generating turbine, while the low-pressure steam is condensed into water. The water is recycled back to the steam generator for reuse. [6] Vogtle-1 and Vogtle-2 each have a net capacity of approximately 1150 MW. [3]
In February, the US NRC granted approval in a 4-to-1 decision for the construction and operation of two new reactors by Southern Company, which is responsible for $6.1 billion of the $14 billion dollar project. [2,4,7] The new units, Vogtle-3 and Vogtle-4, are expected to be operational by 2016 and 2017, respectively, with energy costs of $0.03-$0.035/kWh. [2,8] Each reactor is a Westinghouse AP1000, an advanced passive two-loop PWR with a capacity of 1117 MW [3,8]. Some of the features in the AP1000 include:
The AP1000 has a greater power output than its predecessor, the AP600, and costs 20-30% less than current reactors. Westinghouse claims that the reduction in pumps, piping, and building volume by 35%, 75% and 50%, respectively (compared to the AP600) should simplify operation and improve safety. [8]
The AP1000 safety system relies on gravity and convection and therefore, requires no operator or AC power support, allowing for long-term cooling in the event of a power failure or natural catastrophe like the ones that preceded the Fukushima-Daiichi disaster. [9] The safety valves are fail-safe, so any loss of power causes them to open into a safety-alignment. A passive residual heat removal exchanger protects the plant against transients that could perturb the normal steam generator feedwater and steam systems, while a passive containment cooling system serves as the safety-related heat sink and pressure reducer in case of an accident (pressure will be reduced to an estimated 40% of design value in 5 hours). [8]
The license approval for the Plant Vogtle Expansion was met with opposition from a dozen environmental and anti-nuclear groups concerned that the new design did not sufficiently implement the lessons learned from the Fukushima-Daiichi disaster. [1, 2, 4] Others are concerned about the construction time and cost of the new reactors, especially since nuclear power plants have typically exceed their time tables and budgets. for example, Vogtle-1 and Vogtle-2 took fifteen years to build and were in $8 billion over budget. [7]
Long-term nuclear waste management still remains to be addressed. As of 2001, the United States held more than 40,000 tons of spent nuclear fuel and 100 million gallons of radioactive waste. [10] In 2002, the US Department of Energy proposed that Yucca Mountain be used as a waste repository, but in 2011, all federal support was removed from the project. [11] An alternative to long-term storage is to reprocess the waste, but this option is not favorable due to its expense, high risk of environmental contamination, and moreover, the production of plutonium, which is an added liability. [12]
With 64% of Americans currently opposed to building new nuclear reactors, a nuclear renaissance is still a long way from reality. [1] A change in the attitude of citizens and policymakers in favor of nuclear energy will require better and more rigorous answers to the list of unresolved issues, as well as an earned trust from the public. The success of the construction and operation of Plant Vogtle will be an opportunity to shape the American perception of nuclear power as a viable alternative to carbon-based sources. However, only time will tell if this pivotal point is the true beginning of a nuclear renaissance.
© Stephanie Lam. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] S. DiSavnio and E. O'Grady, "Analysis: U.S. Nuclear Industry's Fate Rests with Southern Co," Reuters, Feb 2012.
[2] "The 30-year itch", The Economist, 18 Feb 12.
[3] "Nuclear Power Reactors in the World: Reference Data Series No. 2, 2011 Edition", International Atomic Energy Agency, IAEA-RDS-2/31, June 2011.
[4] K. E. Swartz, "Groups Sue to Stop Vogtle Expansion Project", Atlanta Journal-Constitution, 16 Feb 12.
[5] J. Gertner, "Atomic Balm?", New York Times Magazine, 16 Jul 06.
[6] A. Andrews and P. Folger, "Nuclear Power Plant Design and Seismic Safety Considerations", CRS Report for Congress, R41805, 12 Jan 12.
[7] K. Silverstein, "How Many Lives Does Nuclear Energy Have?" Forbes, 19 Feb 12.
[8] T. L. Schulz, "Westinghouse AP1000 Advanced Passive Plant," Nucl. Eng. Design 236, 1547 (2006).
[9] R. Pavey, "Vogtle Lays Groundwork for First U.S. Reactor in Decades," Augusta Chronicle, 22 Nov 09.
[10] "Nuclear Waste: Technical, Schedule, and Cost Uncertainties of the Yucca Mountain Repository Project", US General Accounting Office, GAO-02-191, December 2001.
[11] J. Garcia, "The Yucca Mountain Nuclear Waste Repository", Physics 241, Stanford University, Winter 2012.
[12] "Nuclear Waste: Leave Well Alone", The Economist, 10 Mar 12.
