More attention has been given of late to recent announcements of nuclear power plant closures and threatened shutdowns than to the pursuit of new nuclear technology. Despite current economic challenges to the nuclear power industry, many experts support the ongoing development of nuclear power as an essential part of the mix for long-term world energy needs. Recent polling shows that the majority of Americans still favor the use of nuclear energy to generate electricity and 81 percent of those surveyed stated that nuclear power will be important in meeting the country’s future energy needs.
Given current economics, however, it would be easy to question the ability of the U.S. to build new nuclear plants and make use of advanced nuclear designs. This question was recently answered when the industry achieved an historic milestone in the construction of new nuclear power. In March, South Carolina Electric and Gas (SCG&E) and Georgia Power poured the first new construction “nuclear concrete” in over 30 years at the Summer and Vogtle construction sites, respectively. The historic completion of over 7,000 cubic yards of basemat structural concrete at each site by CB & I (formerly Shaw Group) serves as the foundation for the nuclear island structures, such as the containment and auxiliary buildings.
Georgia Power and SCG&E (and their co-owners) are building two Westinghouse AP1000 reactors at each of the Vogtle and Summer locations. Westinghouse and CB&I are even further along in building four AP1000s in China. Design certification of the AP1000 by the NRC was issued in December 2011 and the licenses for construction and operation (COLs) were issued in February 2012 for Vogtle and March 2012 for Summer.
The building of these advanced reactors in Georgia and South Carolina is significant and demonstrates that nuclear power will continue to play an important role in the U.S. energy mix. Their presence also reinforces the need for key stakeholders to support and continue to invest in nuclear reactor technology. According to the World Nuclear Association (WNA), the certification of the AP1000 required 1,300 person-years of work and $440 million for the design and testing program.
Notably, at the time of the Fukushima disaster, the Westinghouse AP1000 was not yet fully certified and the COL had not yet been issued by the NRC. The passive safety features of the AP1000 design provide 72 hours of cooling by way of stored energy and gravity in the case of a major event, which protects public safety as well as the asset. Russ Bell, the Senior Director of New Plant Licensing at the Nuclear Energy Institute (NEI), points out that one year after Fukushima, the NRC was able to proceed with the licensing of the AP1000 at Vogtle and Summer in part because of the robustness of its enhanced safety features. “There is a lot of credit to go all around—Southern Nuclear, SCANA (SCE&G’s parent company), Westinghouse, the NRC, and many others.”
TERRAPOWER’S TRAVELING WAVE REACTOR PROTOTYPE
At least one high-profile investor, Microsoft Corp co-founder and Chairman Bill Gates, touts the benefits of nuclear power and calls for more investment in nuclear energy research. At the international energy executives’ conference in March—CERAWeek, Gates endorsed nuclear power as the best long-term solution to meeting rising world energy needs while addressing climate change because only nuclear provides reliable, high capacity, low-carbon energy in a way that can significantly reduce global warming. Gates also discussed how after the Fukushima accident, there is a greater demand for more stable nuclear energy technology with improved nuclear power reactor designs with greater inherent safety features. There are multiple improvements in nuclear reactor technology already being realized—and there are dozens of new reactor designs being pursued and significant innovations on the horizon.
THE VOGTLE UNIT 3 REACTOR VESSEL IN FRONT THE UNITY 4 CONTAINMENT VESSELL BOTTOM HEAD, MAY 2013. COURTESY OF GEORGIA POWER.
GENERATIONS OF NUCLEAR TECHNOLOGY
The U.S. Department of Energy (DOE) has adopted a nomenclature to categorize various stages of advancement in the development of nuclear energy technology. The progression from one “generation” to the next tells a story of technology evolving to meet needs for increased safety and economy as well as proliferation resistance and reduced nuclear waste material.
VOGTLE UNIT 3 COOLING TOWER CONSTRUCTION, MAY 2013. COURTESY OF GEORGIA POWER.
•Generation I reactors were the prototypes, the first civil reactors developed in the 1950s and 60s that moved the technology from research and military uses to commercial power. They were typically small and lacked the redundant safety systems and non-proliferation aspects of current designs. Exelon’s Dresden Unit 1 (now retired) is of the first generation.
• Generation II reactor designs comprise the vast majority of nuclear plants in operation in the world today. These are commercial nuclear power reactors designed to be economical and reliable and built primarily in the late 1960s through the 90s worldwide. They include the boiling water reactor (BWR), pressurized water reactor (PWR), and the Canadian CANDU reactors. In the west, most were built by Westinghouse, GE and Framatone (ARE-VA). They use active safety features, as opposed to passive, that involve electrical and mechanical operations initiated automatically and/or by the unit operators.
•Generation III and Gen III+ reactor designs reflect significant design improvements and are referred to as Advanced Nuclear Power Reactors. There are dozens of third generation designs that are under development, going through the licensing and certification process or under construction (some Gen III units have been in operation in Japan). According to the World Nuclear Association, third generation reactor designs have the following improvements:
• Standardized design—reducing capital cost, construction time and expediting licensing.
• Simpler and more rugged design—making them easier to operate and less vulnerable to error.
•Longer operating life—typically 60 years.
• Reduced possibility of core melt accidents.
• Passive safety features and long grace period during a shutdown—passive cooling and containment requires no active intervention.
•Greater fuel efficiency—longer fuel life and less fuel waste by-products.
• Resistance to serious damage and radiological release from an aircraft impact.
The major difference between Gen III and Gen III+ designs is that the latter incorporated significant safety improvements that do not require active controls or operator intervention, but rely on gravity and natural convection to mitigate the impact of an event. After the reactor events at the Fukushima Daiichi units, the importance of passive, naturally occurring safety features in the event of a loss of all back-up power became patently clear. The AP1000 is a Gen III+ reactor design.
Other third generation reactor designs pursuing certification include the APR 1400 led by Korea Electric Power Company (KEPCO), US EPR by Areva, the ABWR and ESBWR by GE Hitachi, and the US-APWR by Mitsubishi Heavy Industries.
Small Modular Reactors (SMRs) are third generation designs that have received broad support. SMRs provide advantages in their modular construction and smaller size, which impacts cost, time for construction, and location. Most SMR designs employ advanced passive safety features. The DOE awarded Babcock and Wilcox’s mPower a maximum of $452 million in matching funding to support certification and licensing of its 180 MWe SMR. mPower’s anticipated deployment is approximately 2022. The DOE is taking applications for a second SMR design funding opportunity. Other companies pursuing an SMR reactor design include Holtec International, NuScale Power and Westinghouse.
VOGTLE UNIT 3 CR10 “CRADLE” ON CONCRETE AND STEEL BASEMAT INSIDE THE “NUCLEAR ISLAND,” VOGTLE 1 & 2 OPERATING UNITS IN THE BACKGROUND, MAY 2013. COURTESY OF GEORGIA POWER.
Generation IV reactor designs are in the concept stage, require extensive fundamental research and could be built then commercially deployed beginning in the late 2020s or the 30s. The Generation IV International Forum (GIF) was formed in 2001 to bring global resources to bear on Gen IV reactor research and development and to coordinate efforts for best results. There are 12 member countries including the U.S. DOE. According to the DOE, the objectives of the Gen IV designs are:
•Sustainability—meeting clean energy goals, utilizing fuel more effectively.
• Significantly reduced nuclear waste and long-term stewardship burden.
• Safety and reliability—a low level of reactor core damage in the case of an accident and reduced need for offsite emergency response.
•Economic competitiveness—with a lifecycle cost advantage over other energy sources.
• Proliferation resistance and physical protection.
With any future regulatory effort to capture fees for carbon allowances, nuclear power’s estimaed share of generation increases anywhere from 7-18%, taking the gains from coal.
Six reactor technologies have been selected by GIF for further research and development. Five of the designs recycle nuclear material and produce less waste. China has begun construction of a prototype Gen IV reactor.
Bill Gates has invested in TerraPower, a Bellevue, Washington-based company that is working on the development of a Gen IV technology, the traveling wave reactor (TWR). The TWR is a safer form of breeder reactor that would have no fuel recycling or reprocessing needed because of an intrinsically higher burn-up rate of waste byproduct. TerraPower is working on a prototype reactor to be built around 2022, with an ambitious goal of commercial operation in the late 2020s. The TWR-P would possess all the safety and security benefits of the Gen III+ reactors, but would generate at least seven times less waste than current reactor technology with 50 times the fuel efficiency.
But will we continue to need nuclear power?
The National Renewable Energy Laboratory (NREL) recently released a study that was interpreted by some as concluding that renewables such as wind and solar can provide the vast majority of America’s electricity. However, an April Washing-ton Post article analyzed the study and reached different conclusions. The Post stated that the limits of renewable energy reinforce the need to more aggressively explore next generation nuclear technologies that can provide better safety, nuclear waste, and security (non-proliferation) solutions that can be more economical to build. Although renewables are and will continue to be an important part of the U.S. energy portfolio, most experts conclude that they will not be able to dominate the energy mix, though they certainly can become a bigger play.
Looking at the long-term energy picture reveals that nuclear power will continue to have a key role. According to the U.S. Energy Information Administration (EIA), nuclear power’s share of the electricity mix is expected to decrease by only 2% by 2040, losing some ground to natural gas and renewables, which will also absorb increases in demand. With any future regulatory effort to capture fees for carbon allowances, nuclear power’s estimated share of generation increases anywhere from 7-18%, taking the gains from coal. Global long-term estimates show that nuclear power’s overall proportion of electricity generation stays fairly constant, with losses in Europe and gains in Asia, according to the International Energy Agency.
In sum, nuclear power will continue to be a significant electricity generator in the U.S. and internationally. Advanced nuclear technologies currently being realized bring significant advantages over current reactors. Future technologies hold even more promise to enhance the safety, security and economics of nuclear power while incorporating nuclear waste solutions( Source : Nuclear Power International )
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