Small modular nuclear reactors can complement large-scale projects by expanding the level of deployment and application options for carbon-free nuclear energy. Small-scale reactors provide energy companies and others with a diverse array of energy options.
April 2011Key Facts- Near-term construction of large, new nuclear plants will address two of our nation’s top priorities: additional supplies of clean energy and job creation. Small, modular reactors can complement these large-scale projects by expanding the level of deployment and application of carbon-free nuclear energy. Small-scale reactors provide energy companies and other users with a broader array of energy options.
- Their small size—typically fewer than 300 megawatts (MW)—and modular construction will allow these reactors to be built in a controlled factory setting and installed module by module, reducing the financing challenge and matching a variety of needs for low-carbon energy. [1]
- The potential applications for small reactors include electricity generation. Small reactors may be more compatible with the needs of smaller U.S. utilities from the standpoint of generation, transmission and financing than large 1,400-MW plants. In some cases, the industry envisions modular reactors built in clusters, with modules added as needed to match growth in energy demand.
- Small, modular reactors could be used for industrial process heat applications, such as those used in the petrochemical industry, desalination or water purification.
- Another use for small reactors is providing power for the development of liquid transportation fuels from North American resources of oil sands, oil shale and coal-to-liquids applications, reducing the overall life-cycle carbon footprint of these activities.
Designs Target Diverse ApplicationsMany small, modular reactor designs are under development to meet specific U.S. and international market needs, and they are attracting considerable attention from Congress and the news media. The international community has been evaluating the feasibility of small reactor technologies for the past several years through the
Generation IV International Forum. [2] The forum has identified six technologies for development.
In addition to small light-water reactors, the U.S. Department of Energy is focusing its efforts on two advanced reactor technologies: a high-temperature gas reactor (HTGR) and a sodium-cooled fast reactor (SFR). The Energy Policy Act of 2005 authorized research, development and construction of an HTGR. DOE is pursuing this design through its Next Generation Nuclear Plant project. The SFR technology is being studied as a method for managing high-level radioactive wastes.
Design activities are progressing in each of the three technologies. Each technology has unique development needs and a different timeline for reaching the market. Initial regulatory applications are expected within the next few years for NRC design certifications and combined licenses for prototype reactors.
Light Water ReactorsSmall light water reactors are designed to capitalize on the benefits of modular construction, ease of transportation and reduced financing, all of which could create a compelling business case. Since these designs typically are smaller than 300 megawatts electric, they could be used to replace older fossil-fired power stations of similar size that may no longer be economical to operate in a carbon-constrained world. The infrastructure, cooling water, rail and transmission facilities already exist at such facilities. Designs under development include:
- Babcock & Wilcox Co. mPower Reactor. The mPower reactor design is a 125-megawatt (electric) advanced light water reactor design that uses natural phenomena such as gravity, convection and conduction to cool the reactor in an emergency with a below-ground containment.
- Holtec International. The company has completed initial studies on a 140-megawatt modular reactor, the HI-SMUR 140, whose core is intended to be built underground. It can be installed at a site as a single unit or a cluster.
- NuScale Power Inc. NuScale Reactor. The NuScale is a 45-megawatt (electric) advanced light water reactor. The design is scalable, allowing for a single facility to have just one or up to 24 reactor modules.
- Westinghouse Small Modular Reactor (SMR). The Westinghouse SMR is a 200-megawatt light water reactor design that builds on the concepts and advances in the company’s NRC-certified AP1000 design.
High-Temperature Gas-Cooled ReactorsAlthough high-temperature gas-cooled reactors could be used for electricity generation, they are especially well-suited for providing process heat for industrial applications, including hydrogen production. These reactors also could be used for the development of liquid transportation fuels from North American resources of oil sands, oil shale and coal-to-liquids applications, reducing the overall life-cycle carbon footprint of these activities. Designs under development include:
- AREVA Antares. AREVA based the design for the Antares on the concept of a gas-cooled (helium) reactor. The company is developing the design in the context of the Generation IV International Forum.)
- General Atomics Gas Turbine Modular Helium Reactor (GT-MHR). The GT-MHR is a high-temperature reactor with advanced gas turbine technology.
- Pebble Bed Modular Reactor Ltd. PBMR. The PBMR is a high-temperature reactor that uses a gas or steam turbine for power conversion. Substantial design, component testing and fuel development have been undertaken in South Africa.
Liquid Metal-Cooled and Fast ReactorsLiquid metal-cooled and gas-cooled fast reactor technologies hold the promise of distributed nuclear applications for electricity, water purification and district heating in remote communities. These types of reactors also could provide nuclear fuel cycle services, such as breeding new fuel and consuming recycled nuclear waste as fuel. They could support government-sponsored nonproliferation efforts by consuming material from former nuclear weapons, thus eliminating them as a threat.
- GE Hitachi (GEH) Nuclear Energy Power Reactor Innovative Small Module (PRISM). The PRISM is a 299-megawatt advanced reactor cooled by liquid sodium. As with some other small reactor designs, the plant will be built underground on seismic isolators to dampen the effects of earthquake motion.
- General Atomics Energy Multiplier Module (EM2). The EM2 is a modified version of General Atomics’ high-temperature, helium-cooled reactor. The 240-megawatt reactor is capable of converting used nuclear fuel into electricity and industrial process heat without conventional reprocessing.
- Hyperion Power Generation Hyperion Power Module (HPG). The HPG is a 25-megawatt reactor. Company officials say the module's initial application is likely to be in oil shale fields. Each HPM-based plant can be configured for steam only, co-generation or electricity only.
- Toshiba 4S (Super-Safe, Small and Simple). The 4S is a 10-megawatt reactor cooled by liquid sodium for use in remote locations.
Summary Small, scalable nuclear power plants are an important addition to America’s energy mix, helping to keep the air clean and enhance energy security. Small reactors can replace inefficient fossil-fired facilities, provide process heat for diverse industrial applications and generate electricity for remote locations. Modules can be added as needed—built in controlled factory settings and easily transported to the site, where they will operate without refueling for anywhere from two to 10 years, depending on the design. Together with large reactors, they comprise a full product line of clean, safe, secure carbon-free energy sources.
[1] Megawatt electric or thermal equivalent for non-power reactors.
[2] Existing U.S. reactors are Generation II and III designs. The advanced reactors now under licensing review at the U.S. Nuclear Regulatory Commission are Generation III+. Next-generation reactors are termed Generation IV designs.