SMR Background Information
Excerpt from Nuclear Energy and Development Roadmap - Report to Congress - April 2010
In the United States, it is the responsibility of industry to design, construct, and operate commercial nuclear power plants. However, DOE has statutory authority under the Atomic Energy Act to promote and support nuclear energy technologies for commercial applications. In general, appropriate government roles include researching high-potential technologies beyond the investment horizon of industry and also reducing the technical risks of new technologies. In the case of new commercial reactor designs, potential areas of NE involvement could include:
• Enabling new technologies to be inserted into emerging and future designs by providing access to unique laboratory resources for new technology development and, where appropriate, demonstration.
• Working through the laboratories and universities to provide unique expertise and facilities to industry for R&D in the areas of:
- Innovative concepts and advanced technologies.
- Fundamental phenomena and performance data.
- Advanced modeling and simulation capabilities.
- New technology testing and, if appropriate, demonstration.
- Advanced manufacturing methods.
Representative R&D activities that support each of the roles stated above are presented below. The level of DOE investment relative to industry investment will vary across the spectrum of these activities, with a generally increasing trend in DOE investment for longer-term activities. Finally, there is potential to leverage and amplify effective U.S. R&D through collaborations with other nations through multilateral and bilateral agreements including the Generation IV International Forum, which is investigating multiple advanced reactor concepts. DOE is also a participant in OECD/NEA and IAEA initiatives that bear directly on the development and deployment of new reactor systems.
Accelerate Advancements in LWR Designs
Given the maturity of the Gen III+ LWR designs, R&D needs are necessarily limited, as the design of these plants is well underway or already complete, some of them are being built overseas, and many have been ordered in the United States and elsewhere. Nevertheless the R&D topics identified jointly with industry for R&D Objective 1 are all applicable to this task.
R&D of more advanced LWR concepts, including novel materials, fuels, and innovative system architectures, is a legitimate role for DOE and its laboratories in partnership with industry. This R&D will help address long-term trends in the capital cost of large LWR plants. Much of this research is also expected to be applicable to non-LWR technologies.
Accelerate the Development of SMR Designs
Several U.S.-based companies are seeking to bring new SMR designs to market, including some with potential for deployment within the next decade. Many of these designs use well-established light-water coolant technology to the fullest extent possible to shorten the timeline for deployment. As such, R&D needs for these technologies are minimal. However, these designs may include new features, such as the use of an integral primary system reactor (IPSR) design and components that are not currently used in commercial plants, such as helical-coil steam generators. DOE will hold workshops with LWR SMR vendors and suppliers, potential utility customers, national laboratory and university researchers, DOE, NRC, and other stakeholders to identify potential priorities to enable their commercialization and development. The Administration will evaluate potential priorities in the context of the appropriate federal role to identify the most cost-effective, efficient, and appropriate mechanisms to support further development.
SMR designs that are not based on LWR technology have the potential to offer added functionality and affordability. In this area, NE will support a range of R&D activities, such as basic physics and materials research and testing, state-of-the-art computer modeling and simulation of reactor systems and components, probabilistic risk analyses of innovative safety designs and features, and other development activities that are necessary to establish the concept’s feasibility for future deployment. For SMRs that are based on concepts with lower levels of technical maturity, the Department will first seek to establish the R&D activities necessary to prove and advance innovative reactor technologies and concepts. The Department will support R&D activities to develop and prove the proposed design concepts. Emphasis will be on advanced reactor technologies that offer simplified operation and maintenance for distributed power and load-following applications and increased proliferation resistance and security.
Activities will focus on showing that SMRs provide an innovative reactor technology that is capable of achieving electricity generation and performance objectives that meet market demands and are comparable, in both safety and economics, to the current large baseload nuclear power plants.
NE may also support the development of new/revised nuclear industry codes and standards necessary to support licensing and commercialization of innovative designs and, consistent with NRC guidance and regulations, identify activities for DOE funding to enable SMR licensing for deployment in the United States.
Develop Advanced Reactor Technologies
Future-generation reactor systems will employ advanced technologies and designs to improve performance beyond what is currently attainable. Moving beyond LWR technology, for example, may enable reactors to operate at higher temperatures and improved efficiencies resulting in improved economics. Advanced materials may make reactors easier to construct while also enabling better performance. Improved designs utilizing these advances could reduce the capital costs associated with the current set of reactors being considered. Two prominent examples of advanced reactor technologies worthy of further investigation include:
- The high temperature gas-cooled reactor (HTGR), a graphite moderated thermal-spectrum reactor operated at high temperature for efficient generation of electricity and heat delivery for non-electric applications.
- Fast-spectrum reactors that could provide options for future fuel cycle management and could also be used for electricity generation (see R&D Objective 3).
The U.S. is also a member of the Generation IV International Forum, which is investigating additional advanced reactor systems that employ comparatively less mature technologies while offering significant potential for performance, safety, and economic advances.
Key areas of R&D for future systems could include:
- High-performance materials compatible with the proposed coolant types and capable of extended service at elevated temperatures.
- New fuels and cladding capable of irradiation to high burnup.
- Advanced heat delivery and energy conversion systems for increased efficiency of electricity production.
- Advanced modeling and simulation tools that can reduce uncertainties in predicted performance, improve characterization of uncertainties, and streamline the design of new reactor technologies.
- Systems design for revolutionary new reactor concepts.
Develop Technologies Consistent with Both Electric and Non-Electric Applications
An additional potential benefit from nuclear power could be realized through new plant designs that would be used to displace GHG-emitting fuels in the industrial sector while also generating electricity. Some industrial process heat applications require temperatures substantially above the 300–325°C outlet temperature of today’s LWRs. Petroleum refining, for example, requires temperatures in the range of 250-500°C while steam reforming of natural gas requires process heat in the 500-900°C range. Achieving higher output temperatures requires switching to a new coolant technology such as gas, liquid metal, or molten salt. With these coolants, it may be possible to achieve outlet temperatures ranging from over 500°C for liquid metal coolants to over 900°C for helium or molten salt coolants. Achieving these temperatures, however, will require the development and qualification of fuels, materials and instrumentation, particularly at the higher end of the temperature range. Also, the use of coolants other than water will require the development of a variety of plant components and systems such as electromagnetic pumps for liquid metal coolants, compact heat exchangers for gas coolants, and chemical purification systems for molten salt coolants. These coolants will also require the development of new licensing requirements and codes and standards. While the economic market for dedicated process heat from nuclear power may be limited, reactors that could produce electricity as well as industrial process heat may have broader applications.
Key areas of R&D for future systems could include:
Read the entire Nuclear Energy Research and Development Roadmap
- Develop interfacing heat transport systems – Supply process heat with minimal losses to industrial users within several kilometers of the reactor.
- Develop modeling and simulation capabilities – These tools would improve understanding of interactions between the kinetics of the various reactor types and the kinetics of the chemical plants or refineries, which they would serve. Modeling may also be used to understand the long-term performance of catalysts and solid-oxide cells at an atomistic level.