Searching Questions on New Nukes
Prototype TerraPower’s first full-size fuel assembly is fabricated for the traveling wave reactor in development. Photo Courtesy TerraPower LLC
Modular Plant NuScale adds modules as needed, replacing fuel in one unit while others continue to generate power. Photo Courtesy NuScale Power LLC
Labor-Intensive Critics say conventional nuclear’s costs and schedules are unpredictable. Photo Courtesy Southern Co.
In a power-generation market buffeted by cheap natural gas, increasingly cheap wind and solar energy, demands for carbon-free fuels, environmental regulations, distributed energy resources, advances in energy storage and other innovations and changes, what role can nuclear energy play? In 2015, nuclear generated nearly 20% of electricity and 60% of carbon-free electricity in the U.S., says the Dept. of Energy. “Massive deployment of clean power technologies will be needed by mid-century to meet international commitments” under the Paris Agreement signed in December, DOE added in a draft report released in May.
Four reactors have shut down since 2013; across the country, plans have been announced to close seven others for a total loss of 11,939 MW. If the industry’s tide is receding, it will take with it thousands of megawatts of carbon-free baseload power capacity. In this turbulent market, DOE’s draft report, “Vision and Strategy for the Development and Deployment of Advanced Reactors,” aims to clarify the future of this major generation technology.
The near future looks dark. “U.S. nuclear capacity could begin declining rapidly after 2030 due to a combination of market forces (including strong competition from natural gas generation), remaining useful life considerations, and regulatory effects,” the draft report says. “Sustaining a substantial nuclear presence beyond 2050 will almost certainly require the successful development and deployment of a new generation of advanced reactors.”
Can nuclear compete? Operating costs of the most expensive quartile of nuclear plants are $60 per megawatt-hour, says Arjun Makhijani, president of the Institute for Energy and Environmental Research, Takoma Park, Md. Today, in some parts of the country, utility-scale solar, wind and natural-gas plants cost less to operate than nuclear plants. “What is the point of developing these things?” Makhijani asks.
A new generation of reactors, called Generation IV, has been in development since 2001 by the Generation IV International Forum, an international endeavor set up to carry out the required research and development. The forum has selected six nuclear systems for further development. “The ones that are closest [to commercial deployment] are your high-temperature gas reactors, pebble-bed-type technology or prismatic-block technology,” says Everett Redmond, senior director of fuel-cycle and technology policy for the Nuclear Energy Institute.
Gen IV is not just in the future. “Russia’s been operating sodium-cooled fast reactors on a commercial scale for many years,” says Andrew Sowder, principal technical leader at the Electric Power Research Institute (EPRI). Fort St. Vrain in Colorado was a high-temperature, gas-cooled reactor but closed due to technical issues.
In November 2015, DOE established Gateway for Accelerated Innovation in Nuclear (GAIN), which provides access to the technical, regulatory and financial support necessary to commercialize advanced reactor designs. In January 2016, DOE selected X-energy and Southern Co. to lead public-private partnerships under GAIN to address next-gen reactors’ technical challenges. Southern Co. is supporting the molten-chloride fast reactor, a Gen IV concept being developed by TerraPower. The team, including EPRI, Vanderbilt University and Oak Ridge National Laboratory, will work toward a mid-2020s demonstration.
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TerraPower also is developing a non-Gen IV technology fueled by depleted uranium, a waste product of today’s enrichment process. “TerraPower’s traveling wave reactor offers a new class of advanced fast nuclear reactors that greatly simplify the traditional nuclear fuel cycle, making it cheaper, safer and cleaner,” says Kevan Weaver, technology integration director.
NuScale Power LLC is developing a 50-MW small modular reactor (SMR) using a proven technology: pressurized water. A dozen modules compose a typical 600-MW nuclear plant. Modules can be built in a factory and transported to the site by truck, rail or barge, says Mike McGough, chief commercial officer. Factory fabrication ensures quality control and higher efficiency than field construction, he says. Most important, it reduces the cost impacts of a conventional construction project’s delay, with thousands of workers who may have to be sent home until the delay’s cause is addressed, he adds.
NuScale’s majority investor is Fluor Corp., and the companies are working exclusively to deploy the initial NuScale SMR projects, says Chris Tye, president of Fluor’s power business. NuScale’s first project will be for Utah Associated Municipal Power Systems, which has a tentative agreement with NuScale and Energy Northwest to build a 570-MW NuScale plant at the Idaho National Laboratory. NuScale is responsible for designing, manufacturing and delivering the reactor module to the site, Tye says. As engineer-constructor, Fluor will design and procure the balance of the plant components and oversee installation. Now, NuScale is preparing the combined construction and operating-license application.
While the industry forges ahead, skepticism persists. NuScale has a non-nuclear mock-up and studied thermal hydrology, “but everything else is based on paper studies and idealized” assumptions that don’t account for mishaps, says Edwin Lyman, senior scientist with the Union of Concerned Scientists. Gen IV technologies also suffer from a lack of real-world testing, he adds. Some Gen IV technologies are called advanced, but “they’re really very old technologies that just weren’t pursued for commercial purposes.
“There are companies that do take these things more seriously—for instance, TerraPower,” Lyman says. “They’re actually trying to develop a product that works. I think they’re doing their homework, more or less, and they’re running into problems. They know that it’s not easy to develop an advanced reactor system. It takes a very long time.”
