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Nuclear

New Nuclear Power Plant Designs: the Not So Small Role of Small Modular Reactors

Lauren Rodman and Kristy Hartman 6/27/2014

Approximately 20 percent of the nation’s electricity and 60 percent of the nation’s carbon-free electricity is generated by commercial nuclear reactors. Even as the industry faces an aging reactor fleet, rising construction and maintenance costs, questions regarding safety, and the lack of a national waste storage site, nuclear continues to play an important role in the country’s energy strategy. Growing electricity demand—domestic electricity demand may increase by as much as 29 percent from 2012 to 2040—and a continued effort to use low-emission technologies bode well for the future of the domestic nuclear energy industry. Currently in their design phase, Small Modular Reactors (SMRs), one of the latest nuclear energy technology innovations, may expand opportunities for nuclear power development and help meet energy goals.

What Are SMRs?

Water reactor
Example of a traditional pressurized water reactor (PWR) compared to the B&W mPower SMR design. Reproduced with Permission, 2012 Babcock & Wilcox Nuclear Energy, Inc. All rights reserved.
SMRs are generally defined as nuclear reactor units with a 300 megawatt electrical output or less, or about one-third the size of a typical nuclear power plant. A 300 megawatt SMR could generate enough electricity to power approximately 230,000 homes a year. Compared to traditional reactors—typically 1,000 megawatt or largerSMRs are significantly smaller and anticipated to be more affordable and incorporate passive safety features into their designs. They feature simple, compact designs and have condensed site footprints, with the reactors housed underground. These reactors are small enough to have major components (modules) assembled in factories and shipped by truck, rail or barge and assembled on site. Although SMRs are still in the design phase, several models are expected to be operational by the mid-2020s with the support of federal, state and private investment.

SMR Characteristics

Financial Advantages and Risks

SMRs may also provide financial advantages over large reactors. Because SMRs are small enough to have major components assembled in factories and multiple reactors can be built simultaneously, construction costs may be less than those for large reactors. These small reactors can be added in phases, module-by-module, allowing operators to generate revenue after each module comes online, instead of waiting for a large reactor to be fully constructed. Furthermore, as the development and standardization of SMR designs evolves, the United States’ presence in the international SMR market may grow.

There may be some financial risks associated with SMRs since none of the designs have been licensed or constructed yet. Nuclear reactors are affected by economies of scale; cost per unit increases as size decreases: site footprint per kilowatt capacity dominates much of the material and labor cost, rising as reactor size decreases. Therefore, larger reactors tend to generate cheaper power. Given that SMRs are smaller than traditional nuclear plants, there are uncertainties stemming from the potential increase in cost resulting from the decrease in unit size. It is still unclear whether cost reduction gained by factory manufacturing based on economies of replication will compensate for rising costs associated with changing economies of scale.

Modular

While current nuclear reactors incorporate some factory-fabricated components in their designs, the major component parts are not factory-manufactured and significant on-site assembly is required. However, major component parts of SMRs can be fabricated in factories and shipped to the point of use. With SMRs, their design requires little on-site preparation, reducing construction time and costs. Furthermore, the modular nature of SMRs increases affordability and quality, since they can be manufactured in factories.

Adaptable

SMR reactor
Cross-sectional view of a SMR reactor building. Reproduced with Permission, 2014 NuScale Power, LLC. All rights reserved.

SMRs can be placed in sites typically lacking the infrastructure to support larger nuclear reactors, including in isolated areas, smaller electricity grids, and where land and water are limited. As energy demand increases, SMRS can be added incrementally to load centers, offering utilities the flexibility to scale power production as demand changes. They can also be placed at existing power plants. New requirements to meet U.S. climate goals may force more coal plants to retire, providing the opportunity for SMRs to replace them as a clean energy alternative, using existing power plant sites and connections to the electric grid.

Safety and Security

Design features of SMRs may offer improved safety and security over traditional reactors. The simple and compact design of SMRs reduces the probability of postulated accidents and SMRs can be built below ground, reducing potential threats of a terrorist attack or natural disaster.

Incorporating lessons learned from the Fukushima nuclear accident in Japan, SMRs use passively safe systems— they are designed to safely shut down and self-cool without operator interaction, electricity or water, reducing hazards to operators and others. Proposed SMR models eliminate the need for external piping and instead operate with internal circulation and cooling, bypassing the need and risk associated with reactor coolant pumps. Additional safeguards include containment vessels that control the release of radioactivity and protect the reactor, heat removal systems that offer secondary cooling, and emergency cooling systems that provide heat removal in the event of a total loss of cooling systems.

Some critics of SMRs, however, question their safety and security. Their size and mobility could lead to a greater number of nuclear sites, straining the resources needed to protect the country’s nuclear assets.

Given that SMRs are potentially safer and have more automated characteristics, there are questions over whether security staffing may be diminished at such sites. Additionally, opponents note that locating SMRs below ground may increase their susceptibility to flooding and other risks, potentially making emergency intervention more difficult.

Licensing

While proponents of SMRs point to various advantages, the Nuclear Regulatory Commission (NRC) has yet to certify any of the designs. Licensing rules developed for large reactors contain some similar features to SMRs, but key differences will need to be reviewed before the NRC certifies a design. The commission is currently reviewing policy and technical issues in order to develop a regulatory framework that fits the new technology.

Department of Energy’s Office of Nuclear Energy SMR Licensing Technical Support Program

The U.S. Department of Energy (DOE) announced a cost-sharing program in 2012 to provide $452 million over six years to assist in developing up to two SMR designs. The DOE program provides up to 50 percent of the costs and supports the design, certification and licensing requirements for U.S.-based SMR projects through cooperative agreements with industry partners. DOE selected the mPower America team in November 2012 and NuScale Power in December 2013 for negotiation of financial assistance awards. Both projects plan to deploy SMRs domestically in the mid-2020s.

mPower America Partnership

DOE signed the first cooperative agreement in April 2013 with the mPower America team of Babcock & Wilcox (B&W), the Tennessee Valley Authority, and Bechtel. According to the agreement, DOE could invest up to $226 million to help the B&W mPower reactor design reach commercial application. Under the partnership, Babcock & Wilcox will design the primary system, Bechtel will plan the secondary site and plant layout, and the Tennessee Valley Authority will undertake the site characterization and licensing for operation at the Clinch River Site in Tennessee. Although B&W announced in 2014 that it will restructure its SMR program, it still plans to achieve licensing and deployment by the mid-2020 timeframe.

NuScale Power Partnership

The NuScale Power Partnership focuses on innovation and solutions for enhanced safety, operations, and performance beyond designs currently certified by the NRC. The design eliminates the need for pumps, motors and piping that are found in traditional nuclear power plants. Each NuScale module is 45 megawatts, with a NuScale plant housing as many as 12 modules.

In May 2014, DOE signed a cooperative agreement with NuScale Power, committing up to $217 million in matching funds to be dispersed over the next five years to support the development of its first SMR. NuScale plans to submit a design certification application in 2016 with expected certification in 2020. Commercial operation is expected by 2025.

State Efforts

Several states are exploring ways to support SMR technologies. Since 2010, at least nine states introduced legislation supporting SMR development and at least 10 bills were introduced or enacted in 2013 and 2014. Legislation focuses on creating nuclear energy task forces to explore SMRs, research and development and financing and tax incentive programs.

SMR map

Table 1: Enacted and Pending 2013-2014 Legislation on SMR Technologies

State

Bill Number

Year

Status

Summary

Missouri

HB 2236/2237

2014

Pending

Establishes a nuclear energy standard requiring that two percent of utility retail electricity sales be generated from an SMR, once a facility is developed. The bill will be submitted to the voters for approval or rejection.

New Mexico

HJM 19

2014

Pending

Urges the governor to commission a nuclear energy task force to facilitate nuclear economic development opportunities. Establishes that SMRs and large volume nuclear reactors are a necessity for carbon-free electricity production.

HM 57

2014

Adopted

Requests the Energy, Minerals, and Natural Resources Department to explore the feasibility and economic benefits of constructing and operating a SMR in the state’s energy plan. Tasks the Department with identifying legal and regulatory requirements for constructing a SMR.

Ohio

HCR 43

2013

Pending

Creates a sustainable energy-abundance plan. Encourages the state to pursue R&D of SMR technologies as a long-term solution to Ohio’s energy needs.

South Carolina

SB 525

2013

Pending

Establishes the Clean Energy Industry Manufacturing Market Development Advisory Council and relates to the Clean Energy Tax Incentive Program. Provides tax incentives to companies in the solar, wind, geothermal, hydrogen, energy storage, SMR, and energy efficiency industry.

Washington

SB 5035/HB 1089

2013

Enacted: 2013 Wash. Laws, Chap. 19

Adopts the 2013-2015 capital budget. Appropriates $ 500,000 to the Tri-Cities Development Council (TRIDEC) to facilitate the development of SMRs.

HB 2224/SB 6020

2013

Failed

Relates to the 2013-2015 supplemental capital budget. Appropriates $500,000 to the Tri-Cities Development Council (TRIDEC) to facilitate the development of SMRs.

Source: National Conference of State Legislatures, 2014

Table 2: Previous Legislation on SMR Technologies

State

Bill Number

Year

Status

Summary

Arizona

HCM 2014

2010

Adopted

Relates to nuclear energy plant development. Provides funding for R&D with advanced nuclear fuel cycles, encourages government-private programs for development, and provides R&D for certification and licensing of two small, scalable innovative modular reactor designs.

Iowa

HB 561/SB 390

2011

Failed

Concerns the permitting, licensing, construction, and operation of nuclear generation facilities. Encourages the development of nuclear power generation, including, but not limited to, SMR technology.

Indiana

HR 54

2013

Adopted

Encourages the Legislative Council to assign to the regulatory flexibility committee the task of studying, during the 2013 legislative interim, the topic of small modular nuclear reactors.

Missouri

HB 82

2011

Failed

Allows electricity produced from small modular reactors to be included in an electric utility's portfolio requirements.

HB 767

2013

Failed

Expands the Manufacturing Jobs Act to include qualified investor-owned utilities, including replacement, expansion, or improvement of infrastructure, transmission, or new generation including, but not limited to, SMRs and renewable energy used to provide services.

North Dakota

HCR 3033

2011

Failed

Supports nuclear energy R&D by creating a national nuclear energy council, authorizing multiyear programs, and appropriating funding. Encourages government-private sector cost-shared programs for development, certification, and licensing of two small, scalable innovative modular reactor designs.

Washington

HB 1513

2011

Failed

Promotes the development of nuclear energy facilities. Creates a task force to study the feasibility of new nuclear power reactors and to examine advanced nuclear power reactors, including, but not limited to, small modular nuclear technologies.

S 5564

2011

Failed

Promotes the development of nuclear energy facilities. Creates a task force to study the feasibility of new nuclear power reactors and to examine advanced nuclear power reactors, including, but not limited to, small modular nuclear technologies.

Source: National Conference of State Legislatures, 2014

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