Chapter 9. Nuclear Small Modular Reactors

Introduction

Nuclear power offers a low-emission, high-capacity solution for reliable electricity generation, thus nuclear energy is increasingly viewed as a critical tool for meeting climate goals while ensuring grid stability. Advances in reactor design, including the development of small modular reactors (SMRs), are making nuclear more flexible, scalable, and potentially faster to deploy than traditional large-scale plants. Therefore, this section focuses on SMR that would be co-located with a large load, while full scale nuclear plants are considered part of the grid electric supply. With growing interest in firm, dispatchable, zero-carbon generation, nuclear energy is re-emerging as a central component in long-term decarbonization strategies.

Nuclear fission is a process in which the nucleus of a heavy atom, typically uranium-235 or plutonium-239, splits into two smaller nuclei when struck by a neutron. These splitting releases a large amount of energy in the form of heat, along with additional neutrons. These neutrons can then trigger further fission reactions in nearby fuel atoms, creating a self-sustaining chain reaction. In nuclear power plants, this heat is used to convert water into steam, which drives turbines to generate electricity. Fission is extremely energy-dense—just one gram of uranium-235 can release as much energy as burning over a ton of coal. In fact, one kilogram of uranium-235 can yield up to 24 million kilowatt-hours (kWh) of heat, compared to just 8 kWh from coal or 12 kWh from oil per kilogram, making nuclear fuel millions of times more energy-intensive by weight and a powerful source of baseload electricity. [1]

Nuclear fusion is the process by which two light atomic nuclei—typically isotopes of hydrogen—combine to form a heavier nucleus, releasing an immense amount of energy in the process. This reaction powers the stars, offering the potential for an abundant and clean energy source. However, despite its promise, the development of reactors capable of sustaining, controlling, and efficiently converting fusion energy into usable power remains significantly behind that of nuclear fission. Given these developmental challenges, fusion will not be addressed further in this chapter.

Small Modular Reactors (SMRs) optimize the nuclear fission process through compact, factory-fabricated designs that enhance safety, shorten construction timelines, and reduce capital costs compared to traditional large-scale reactors. Many SMRs incorporate advanced cooling technologies, including passive safety systems that rely on natural circulation and gravity rather than pumps or external power sources—significantly lowering the risk of overheating or meltdown. Their modular architecture enables phased deployment to match load growth, making them particularly suitable for remote locations and smaller electrical grids. Some designs utilize high-assay low-enriched uranium (HALEU), which allows for higher fuel burnup and extended operating cycles, boosting fuel efficiency. Collectively, these innovations preserve the fundamental principles of nuclear fission while offering improved flexibility, scalability, and resilience.

Despite their potential, SMRs remain in the early stages of deployment. As of 2025, no SMRs are operational in the United States, although several designs—such as NuScale’s VOYGR—have received partial regulatory approval. Commercial rollout faces hurdles including cost uncertainty, supply chain limitations, and public and regulatory skepticism. Nonetheless, momentum is building. The U.S. Nuclear Regulatory Commission approved NuScale’s design in 2023, marking a milestone, even as the company’s Carbon Free Power Project was canceled due to rising costs. Meanwhile, TerraPower and X-energy are advancing demonstration reactors under the DOE’s Advanced Reactor Demonstration Program, targeting operational prototypes by the early 2030s. Internationally, Canada is making strides with multiple SMR initiatives, including Ontario Power Generation’s collaboration with GE Hitachi on the BWRX-300. These efforts highlight both the promise and complexity of bringing SMRs from concept to commercial reality. [2]

1 Deployment Schedule

The development schedule for Small Modular Reactors (SMRs) is shaped by a complex mix of regulatory, technical, financial, and logistical factors. Unlike traditional power plants, SMRs must navigate a rigorous licensing process unique to nuclear energy, followed by intricate procurement, specialized construction, and tightly controlled startup procedures. While SMRs are designed to streamline many of these steps through modularization and factory fabrication, early deployments—particularly first-of-a-kind (FOAK) projects—face added scrutiny and coordination challenges. This section breaks down the key phases of SMR development, including permitting, interconnection, procurement, construction, and commissioning, to illustrate the full timeline from licensing to grid connection. As more SMRs are built and supply chains mature, future deployments may see shortened timelines, but initial projects must contend with a layered and evolving development process.  The total timeline for FOAK SMRs—considering pre-licensing activities, regulatory review, supply chain mobilization, and construction—can still span 7 to 10 years. Over time, as more units are built and processes are standardized, future SMR deployments may accelerate to as little as 3 to 5 years per unit. [3]

Permitting & Regulatory Approvals

Small Modular Reactors (SMRs) must navigate a comprehensive federal licensing process overseen by the Nuclear Regulatory Commission (NRC). This typically involves three stages: design certification, which approves a reactor design; site permitting or Early Site Permits (ESP); and the Combined License (COL), which authorizes construction and operation at a specific location. If a developer applies with a non-certified design, they may follow a two-step process starting with a Construction Permit (CP). [3] These steps require extensive safety, security, and environmental reviews, public comment periods, and technical hearings. For example, NuScale’s design certification process lasted about four years (2016–2020), not including pre-application engagement. COL approval itself can take 3 to 5 years, depending on the technology, whether the design is pre-certified, and the thoroughness of the application. [4]

The NRC is developing a new framework—10 CFR Part 53—to streamline licensing for advanced and non-light-water SMRs, but as of 2025, most developers still proceed under existing Part 50 or Part 52 rules. Beyond federal review, developers must secure additional permits at the state and local levels, including NEPA environmental assessments (typically 18–24 months), approvals from the EPA and U.S. Army Corps of Engineers, state utility commissions, and local or tribal land use authorities. These layers of permitting can add 1 to 3 years to the timeline, especially for projects crossing jurisdictional boundaries or involving federal land. [3]

Once licensed and permitted, construction timelines vary by design. NuScale claims its factory-fabricated modules can be installed and brought online within 36 months after first safety-related concrete is poured. [5] X-energy’s Xe-100 reactor estimates a 2.5 to 4-year onsite construction timeline from site prep to startup for a 300 MWe deployment. [6] These durations assume streamlined assembly and minimal delays—conditions more likely after initial units have demonstrated successful deployment. Future projects may benefit from licensed designs, pre-approved sites, and a more responsive regulatory framework—but early deployments must still overcome a multi-layered and evolving permitting process.

Several companies are leading the development of Small Modular Reactor (SMR) technologies in the United States. NuScale Power (Portland, OR) is advancing its VOYGR design, a light-water reactor recently approved by the NRC. TerraPower (Bellevue, WA), founded by Bill Gates, is developing the sodium-cooled Natrium reactor with backing from DOE’s ARDP program. X-energy (Rockville, MD) is commercializing its Xe-100 high-temperature gas reactor, designed for both electricity and process heat. GE Hitachi Nuclear Energy (Wilmington, NC) is promoting its BWRX-300, a simplified boiling water reactor targeting rapid deployment. Holtec International (Camden, NJ) is pursuing the SMR-300, a pressurized water reactor designed for compact site footprints and passive safety. These companies represent the forefront of domestic SMR innovation, each with distinct reactor technologies and commercialization strategies. [7]

The development time for Small Modular Reactors (SMRs) is influenced by a combination of regulatory, technical, financial, and logistical factors. One of the most significant contributors to delays is the complex and lengthy regulatory process. First-of-a-kind (FOAK) designs, especially those using non-traditional fuels or cooling methods, often face extended reviews by the Nuclear Regulatory Commission (NRC), with design certification and construction permitting alone typically taking three to six years. Even SMRs based on familiar light-water reactor technology can encounter delays due to the need for site-specific environmental impact assessments, emergency planning zone adjustments, and public comment periods. Additionally, SMRs depend heavily on factory-based modular construction, which requires the development of a reliable supply chain and specialized manufacturing facilities—something that’s still in progress for many developers. The use of advanced fuels, like high-assay low-enriched uranium (HALEU), adds further complexity due to limited commercial availability and ongoing fuel qualification requirements. Financing can also delay development, as SMR projects require large upfront investments despite the promise of lower long-term costs, and lenders may be cautious without proven deployment histories. Once permits are secured and manufacturing is underway, on-site construction and assembly of modules can be completed in roughly two to four years, which is significantly faster than conventional nuclear plants.

Interconnection

The interconnection process for Small Modular Reactors (SMRs) typically spans 24 to 48 months, depending on site conditions, grid readiness, and regulatory coordination. This duration includes transmission planning, system impact studies, permits, and the construction or upgrade of substations and transmission lines—often making interconnection one of the longest lead-time items in SMR deployment.

Like other generators, SMRs must comply with standard grid requirements for voltage control, reactive power, and protection systems. However, nuclear projects face additional complexities due to their regulatory classification and operational needs. SMRs are designed to provide stable, dispatchable baseload power, but they depend on a stable external grid during startup, especially to power safety systems and auxiliary loads. As a result, grid support is essential during black start scenarios, and SMRs cannot easily operate in isolation without extensive control integration.

Further complicating the process, SMR interconnections are subject to dual oversight—from both the Nuclear Regulatory Commission (NRC) and grid operators or transmission providers, such as Independent System Operators (ISOs) or Regional Transmission Organizations (RTOs). Nuclear-specific concerns, including cybersecurity, safety margins, physical security zones, and redundant control systems, may require additional protective relaying, secure communication networks, and longer review times.

Procurement

Procurement times for Small Modular Reactors (SMRs) are shaped by a complex mix of technical, regulatory, and supply chain factors. A major contributor is the limited global availability of nuclear-grade components, such as reactor pressure vessels, steam generators, and control systems, which must meet stringent quality standards like ASME Section III and NQA-1. These requirements significantly narrow the pool of qualified vendors and can extend lead times to 12–36 months for key components. The challenge is even greater for first-of-a-kind (FOAK) designs that require custom-engineered parts or novel materials, as these must undergo additional testing, validation, and certification before production can begin. Furthermore, advanced SMRs that rely on High-Assay Low-Enriched Uranium (HALEU) face bottlenecks due to the current lack of commercial-scale HALEU production, creating fuel procurement delays. Even once designs are finalized, vendors often wait for full NRC licensing and design approval before fabricating components to avoid costly rework, which adds further time. Limited manufacturing capacity in the nuclear supply chain—especially after decades of underinvestment—means that fabricators may already be operating at full capacity or lack the skilled workforce to rapidly scale up. In addition, logistics and coordination between multiple suppliers—especially for modular construction—introduce complexity and risk of delay. Global factors such as geopolitical instability, steel shortages, and transportation backlogs can also disrupt material availability. As a result, procurement for SMRs can be a critical path item in the development timeline, particularly for early projects, though repeat builds with standardized components and pre-qualified vendors are expected to see significantly shorter procurement times.

Construction & Start-Up

Construction times for SMRs are influenced by a combination of regulatory inspections, site readiness, supply chain logistics, and labor availability. Projects can’t break ground until all permits are secured, and delays in environmental reviews or grid interconnection can stall progress. While modular construction offers faster on-site assembly, it relies on timely delivery of prefabricated components—any delay in fabrication or shipping can halt the schedule. Site-specific challenges like soil conditions, weather, or remote locations can also extend timelines, as can shortages of nuclear-qualified labor. Additionally, first-of-a-kind projects are more prone to design changes or construction errors, which lead to rework and further delays. [3]

Commissioning, start‑up, and turnover of SMRs involve meticulous system verification, testing, and regulatory oversight that can indeed take around six months, though the duration varies by design and deployment context. After construction completion, the plant enters a commissioning phase where all safety, control, and protection systems are tested under operational and accident conditions—with some commissioning guides from the IAEA emphasizing detailed test plans, documentation, and regulatory. Next comes fuel loading and first criticality, which may take several weeks, followed by a series of stepped power ascensions and hot functional tests to confirm performance at design temperatures and pressures. Historically, large reactors like Vogtle associated this phase with a handful of months between fuel loading and grid synchronization. For SMRs, streamlined modular designs and simplified systems are expected to reduce commissioning times to around 4–9 months—though that timeframe could stretch to six months or more for first‑of‑a‑kind builds due to additional validations, regulatory sign‑offs, and performance testing. Once these are successfully completed and inspected, formal handover to operations occurs, marking the final turnover milestone.

2 Operational Capabilities

Small Modular Reactors (SMRs) are designed to deliver reliable, firm power with greater operational flexibility than traditional large reactors. Their compact size and advanced control systems enable faster start times, variable output levels, and improved responsiveness to changing grid demands, making them well-suited for modern, dynamic energy systems.

Dispatchability and Flexibility

Small Modular Reactors (SMRs), due to their compact size, can incorporate more flexible operational strategies compared to traditional large-scale nuclear plants. Some designs use control rod adjustments to modulate power output gradually throughout the day, enabling the reactor to follow daily load profiles and help smooth net demand—such as counteracting midday solar surges or prolonged low-wind periods. Other advanced SMR concepts are designed to respond to minute-by-minute dispatch signals by either bypassing the turbine and sending excess steam directly to the condenser, or by leveraging a behind the meter load or BESS to control how much power is delivered to the grid.[8]

Small Modular Reactors offer greater operational flexibility than traditional nuclear plants. Many SMR designs are capable of load-following, adjusting output to match grid demand in real time. Advanced controls and modular cores allow for quicker ramping, and some designs incorporate thermal storage to support variable renewable generation. Their smaller size also enables deployment in distributed or off-grid locations, enhancing overall system adaptability. Power output can typically range from 100% down to 20% and back up, allowing for a turndown ratio of 5:1. Traditional pressurized water reactor (PWR) designs like NuScale’s SMR utilize steam bypass systems to enable rapid load-following and frequency regulation without impacting core thermal conditions. [9]

Start Times and Ramp Rates

Cold start times for nuclear power plants refer to the duration required to bring a reactor from a complete shutdown to synchronized grid operation. For conventional large-scale nuclear plants, this process typically exceeds 12 hours and can take several days to reach full output. Steps include re-establishing the chain reaction, heating the coolant and steam systems, and gradually ramping up power—all of which require controlled, time-intensive procedures. In contrast, Small Modular Reactors (SMRs) are expected to offer significantly faster cold start capabilities due to their compact size, modular design, and passive safety features. While publicly available data on SMR-specific cold start times is limited, many designs—particularly microreactors and advanced SMRs—are targeting startup times on the scale of hours, rather than days, making them better suited for flexible grid integration and rapid deployment scenarios.

Small Modular Reactors offer a wide range of ramp rates depending on design type, enabling faster response to grid fluctuations than traditional large-scale nuclear plants. Pressurized Water Reactor (SMR-PWR) designs, the only SMR type currently approved by the NRC, achieve 2–5% per minute ramp rates using steam bypass systems for load following and frequency control. Molten Salt Reactors (SMR-MSR) and High Temperature Gas-cooled Reactors (SMR-HTGR) typically reach 5% per minute ramp rates, supported by integrated thermal energy storage. More advanced designs, such as Lead-cooled Fast Reactors (SMR-LFRs), can ramp at 10% per minute, while Heat Pipe Reactors (SMR-HPRs) offer ramp rates of up to 20% per minute by utilizing thermal storage to deliver power in excess of nominal capacity for rapid system response. [9]

Grid Stability and Power Quality

Conventional nuclear power plants contribute significantly to grid stability through high rotational inertia, with inertia constants (H) ranging from 3.8 to 4.34 seconds according to ERCOT data. In contrast, SMRs typically use smaller and lighter turbine-generators, resulting in lower physical inertia. To compensate, many SMR designs incorporate fast-response control systems or synthetic inertia through power electronics, which mimic the effect of spinning mass by rapidly adjusting output in response to frequency changes. This is often achieved using advanced inverter systems that detect grid disturbances and inject power within milliseconds to help stabilize voltage and frequency. [10]

Small modular nuclear reactors (SMRs) show promise in advancing grid power quality through their ability to deliver stable, dispatchable, and high-inertia power, which is increasingly valuable in modern grids with high renewable penetration. Unlike variable renewable sources, and similar to other thermal cycle power plants, SMRs provide consistent voltage and frequency support, helping to stabilize the grid under fluctuating load conditions. Many SMR designs incorporate synchronous generators, which contribute to system inertia—a key factor in resisting frequency deviations. Additionally, emerging SMR technologies are being designed with advanced control systems that can offer reactive power support, voltage regulation, and even black start capabilities, making them versatile assets for grid reliability.

Synchronization and Control

Small Modular Reactors (SMRs) are designed for modular deployment, with individual units typically producing under 100 MWe and added in blocks to match site-specific power needs. This configuration enables staged synchronization with the grid or with other units, offering more precise control than conventional large-scale reactors. Designs like NuScale incorporate fast-response systems such as turbine bypass and digital governors, while others may use synthetic inertia through power electronics to mimic the stabilizing effects of traditional spinning mass. These features allow SMRs to rapidly adjust to grid demands and contribute to frequency support, black-start capability, and grid resilience. [7]

Parasitic Loads and Degradation

Small Modular Reactors are generally expected to have lower parasitic power requirements compared to traditional large-scale nuclear plants. This is due in part to their compact designs, simplified systems, and use of passive safety features. While exact figures vary by design and limited public data is available, estimates suggest that parasitic loads may fall in the range of 4–8% of gross output. For example, integral pressurized water reactor (PWR) designs like NuScale’s reduce the need for active primary loop pumps, which can help limit internal power consumption and improve net efficiency. [5]

Small Modular Reactors do not experience a year-to-year decline in efficiency due to equipment aging. Their thermal and electrical performance remains stable throughout each fuel cycle, with no inherent annual degradation. Any gradual reduction in output is primarily related to fuel burnup as fissile material is consumed, reactivity decreases, which is managed through routine refueling and core design. Over the long term, SMRs are designed for service lifespans of 60 years or more, with potential for license extensions. Structural components are engineered to withstand radiation, pressure, and temperature stress, and routine maintenance ensures continued reliability without the efficiency losses typically seen in other generation technologies.[7]

3 Service Reliability

Small Modular Reactors are expected to offer high reliability through modular designs, digital controls, and subsystem-level redundancy. While full-unit backups are uncommon, individual modules can operate independently, maintaining power delivery even if one unit is offline.

Availability & Failures

Since direct MTBF data for SMRs is not yet available, estimates can be drawn from reliability metrics observed in conventional nuclear power plants. For instance, reactor protection system components often have MTBF values around 1 year, while digital instrumentation and control systems—frequent sources of shutdowns—typically range from 5 to 10 years. [11][12] Some high-reliability systems, like the Westinghouse Common Q platform, claim MTBFs exceeding 70 years, illustrating the potential for long-lasting subsystems. [13] For SMRs, one can reasonably estimate MTBF values of 1–5 years for mechanical components such as pumps and valves, and 5–10 years for digital control systems, depending on design and redundancy. Given their modular architecture and reliance on advanced digital platforms, SMRs are expected to achieve similar or improved MTBF performance compared to traditional nuclear systems, particularly for critical and high-reliability subsystems.

Nuclear energy systems are engineered to operate continuously for extended periods, delivering reliable baseload power with minimal interruption. In the United States, nuclear plants consistently achieve availability levels above 92 percent, reflecting the technology’s durability and well-managed maintenance practices. [14] Capacity factor, which measures the actual energy produced compared to the maximum possible, typically falls between 92 and 95 percent. These high-performance figures are made possible by long fuel cycles, planned refueling outages, and robust system designs that minimize unplanned downtime. [15]

From a reliability standpoint, SMRs and nuclear plants face several key risks that could impact continuous energy production. Unplanned equipment failures, particularly in critical systems like coolant pumps, control rods, or power electronics, can trigger reactor shutdowns and require significant time to diagnose and repair. Fuel supply constraints, such as limited availability of high-assay low-enriched uranium (HALEU), may also delay startup or refueling cycles for some SMR designs. Grid disturbances or loss of offsite power can temporarily halt operations, especially if backup systems are insufficient or fail. Additionally, long maintenance and restart times, common in nuclear systems, mean that even short disruptions can result in extended downtime. Finally, SMRs deployed in modular arrays may face cascading reliability issues if shared systems (like steam lines or control infrastructure) fail, affecting multiple units simultaneously.

While specific Mean Time Between Failures (MTBF) values for Small Modular Reactors (SMRs) are largely theoretical due to limited operational history, industry expectations suggest exceptionally high reliability—comparable to or exceeding that of large-scale nuclear reactors. Traditional commercial reactors routinely achieve MTBFs exceeding 250,000 hours, with very few full-system failures across decades of operation. SMRs aim to build on this performance by incorporating simplified, passive safety systems and standardized factory-built components that reduce the complexity and number of failure pathways. As a result, SMRs are expected to achieve similarly long MTBFs, potentially exceeding 30 years of continuous operation between major failures. This long operational interval, combined with high availability and modular deployment, positions SMRs as a dependable source of baseload power, particularly in applications where consistent, uninterrupted performance is critical.

Redundant & Resilient Architectures

Small Modular Reactors (SMRs) incorporate redundancy at the subsystem level to ensure safety and reliability, often using N+1 or 2N configurations for critical functions such as control systems, cooling loops, and power supplies. These redundancies are essential for meeting regulatory safety requirements and are similar in structure to those used in large-scale nuclear reactors. By designing these systems with built-in fault tolerance, SMRs can maintain safe operation even if one component fails.

However, providing full-module redundancy, such as building an extra reactor solely as a backup, is generally not economical due to the high capital cost of each unit. Instead, SMR installations typically rely on the independent operability of each module, allowing unaffected units to continue operating if one goes offline. To further support reliability, alternative backup systems like diesel generators, battery storage, or hybrid renewable integration are often used. These solutions offer a more practical and cost-effective way to ensure continuous power delivery and safe shutdown capabilities without duplicating entire reactor systems.

4 Environmental Sustainability

Emissions & Air Quality Impacts

While nuclear energy produces no direct air emissions such as CO₂, NOₓ, SOₓ, or particulate matter during operation, its primary environmental concern remains the generation of radioactive waste. Additionally, nuclear power carries indirect life-cycle emissions, averaging around 12 g CO₂e per kilowatt-hour. These emissions result from processes such as uranium mining and milling, fuel enrichment and fabrication, plant construction, maintenance, decommissioning, and spent fuel storage, all of which involve energy use and material handling that contribute to the overall carbon footprint. [16]

Water Usage

Nuclear power, like most thermal plants, relies heavily on water for cooling: once-through systems withdraw nearly 39,000 gal/MWh but consume only about 400 gal/MWh, while recirculating towers greatly reduce withdrawal (~700 gal/MWh) at the cost of higher consumption (~500 gal/MWh). In the U.S., nuclear accounts for approximately 40% of thermoelectric water withdrawals and 28% of consumption. [17]

Advanced reactors and SMRs reduce water use through design innovations that reduce dependence on traditional cooling methods. Many SMRs, such as those from NuScale and Westinghouse, incorporate passive cooling systems and on-site water pools that help manage thermal loads without requiring active pumping. These systems rely on natural circulation and gravity, maintaining safe temperatures even during power outages, which enhances reliability and safety. While some next-generation reactors utilize non-water coolants like gas, molten salt, or liquid metal, water still plays a critical role in power conversion systems and plant support operations. Additionally, applications such as hydrogen production, industrial heat supply, and desalination, all of which SMRs may support, require intermediate water-based systems, reinforcing the importance of thoughtful water management in future deployments. [17]

End of Life & Recyclability

Decommissioning a nuclear power plant typically takes between 15 and 20 years, with total costs for a large-scale facility ranging from $1 to $3 billion. The majority of these expenses are fixed, including facility maintenance, decontamination, and labor, meaning they are not significantly influenced by reactor size. As a result, these fixed costs increase the cost per megawatt for smaller reactors like SMRs. Co-locating SMRs in modular groupings may offer greater economic viability by spreading those fixed costs across more capacity. A study from the University of Pécs found that decommissioning a 50 MWe SMR would cost approximately $1.634 billion, only a 6 percent reduction compared to a 350 MWe SMR at $1.728 billion highlighting the limited cost savings from downsizing alone. [18]

Nearly 95% of a nuclear plant’s contents are recyclable, with only about 5% considered radioactive waste requiring specialized handling. Most of the recoverable materials, metals, concrete, and structural elements, can be safely reused in new applications. This high recyclability transforms the decommissioning process into an opportunity for resource recovery and supports circular economy practices. [19]

Hazardous Materials & Waste Management

Nuclear waste is categorized into low-, intermediate-, and high-level waste, with low-level waste—such as tools, filters, and protective clothing—making up about 90% of the total volume but contributing only 1% of the radioactivity. In contrast, high-level waste, primarily spent nuclear fuel, accounts for just 3% of the volume but holds 95% of the radioactivity. [20] The United States has accumulated over 90,000 metric tons of spent fuel, with an additional 2,000 metric tons generated annually and stored on-site at nuclear power plants due to the lack of a permanent federal disposal facility. [21] For comparison, the entire 55-year U.S. inventory of spent nuclear fuel would occupy the volume of a football field filled to a depth of 10 yards, underscoring the compact nature of nuclear waste. [22] While the U.S. does not currently reprocess spent fuel, countries like France have implemented recycling programs, and it is estimated that over 90% of the potential energy remains in spent fuel after one reactor cycle. [22] Meanwhile, the coal industry produces over 110 million tons of waste annually, much of which remains largely unregulated at the federal level. [23]

5 Site Feasibility

The siting of Small Modular Reactors (SMRs) plays a critical role in their overall feasibility, public acceptance, and long-term success. Unlike many renewable energy technologies, SMRs are not tied to specific geographic resources like wind or solar availability, which gives developers greater flexibility in location selection. This flexibility allows SMRs to be placed closer to existing infrastructure, industrial demand, or retiring fossil fuel sites—reducing both cost and environmental disruption. However, successful siting goes beyond technical fit. It also requires careful attention to land use efficiency, visual and acoustic impact, and community perception. This section explores how SMRs are uniquely positioned to address these factors through compact design, adaptable siting strategies, and a focus on engaging local stakeholders from the outset.

Proximity to Energy Resources & Infrastructure

Siting SMRs requires careful consideration of proximity to both existing infrastructure and supporting energy resources. Unlike wind or solar, SMRs are not location-dependent on a natural resource like wind speed or solar irradiance, giving developers greater flexibility in choosing optimal sites based on infrastructure access, grid stability, and community needs. As a result, many proposed SMR projects are targeting brownfield sites, such as retired coal or fossil fuel plants, where existing grid interconnections, cooling water access, transmission lines, and permitting footprints can be reused or upgraded. This approach can significantly reduce costs and permitting timelines while supporting just transition goals in fossil-dependent regions.

In addition to grid access, SMRs benefit from proximity to cooling water sources, particularly for light-water reactor designs. While dry cooling is possible, sites near rivers, lakes, or coastal regions are often preferred for thermal efficiency. SMRs may also be strategically located near industrial facilities that require combined heat and power (CHP), such as chemical plants, refineries, or data centers, turning proximity into a value-added feature. However, these locations must still meet nuclear siting requirements related to seismic stability, population density, emergency planning zones, and security perimeters, which can limit options in some areas.

By prioritizing sites with existing infrastructure and industrial demand, SMR developers can reduce costs, accelerate timelines, and provide firm, carbon-free power where it’s needed most

Land Use

Nuclear power plants offer high energy output with a relatively small physical footprint. Traditional U.S. nuclear facilities average around 1.2 MW per acre, based on the median land area of 54 plant sites. [24] Small Modular Reactors (SMRs), however, are even more land efficient. A single 300 MWe SMR can be installed on just 3 hectares (7.4 acres), yielding approximately 40 MW per acre. [25] A larger deployment, such as the 12-unit, 920 MW NuScale SMR, occupies only 35 acres—about 26 MW per acre. [26] SMRs also reduce regulatory overhead: NuScale designs are the only NRC-approved SMRs whose emergency planning zone ends at the facility’s fence line, eliminating the need for 10-mile evacuation zones and easing coordination with local governments. [27]

In terms of physical size, SMR generating sites can range from the scale of a three-story office building to the size of a city block. [28] Since SMRs are scaled-down systems, their structural height is also reduced. Both NuScale and Holtec locate most of their reactor modules below grade, enhancing safety and reducing visual impact. Holtec estimates the tallest components of their facilities will be comparable in height to a small municipal water tower. [25]

Aesthetics and Acoustic Considerations

SMRs are designed with a compact physical footprint, which can help limit their visual presence on the landscape. Many SMRs feature low-profile buildings, and some designs place components partially or fully underground, further reducing above-ground structures. When located at existing industrial or brownfield sites, such as retired power plants, SMRs may integrate into the existing setting with minimal additional visual impact. Typical features include access roads, security infrastructure, and support buildings, which are generally consistent with other energy or utility facilities. While all energy technologies have some degree of visual presence, SMRs offer flexible siting options that can help align with local land use goals and minimize aesthetic concerns where appropriate.

Nuclear power plants are relatively quiet from a community perspective, with most operational noise contained within the facility. While sound levels inside turbine buildings can reach around 90 decibels, exterior noise typically falls to about 40 to 45 decibels at a distance of 750 meters, which is comparable to the ambient noise in a quiet residential area. [29] In nearby communities, measured noise levels range from approximately 32 to 48 decibels. Auxiliary systems like emergency diesel generators are only operated during scheduled tests, usually during the day, further minimizing disturbance. [30]

Public Perception & Perceived Harm

Gaining community acceptance is essential for the success of any nuclear project. It’s not just about national support or public opinion—it’s about whether the people living near a facility trust that it will be safe, well-managed, and responsive to their concerns. Incidents like Chernobyl, Three Mile Island, and Fukushima have left a lasting impact on how nuclear power is perceived, especially among communities directly affected by or located near plants. These events are reminders that while severe accidents may be rare, their consequences are serious and long-term.

Public concern about nuclear energy is not simply a matter of misunderstanding. It reflects real questions about safety, waste management, and oversight. The responsibility lies with the nuclear industry and regulators to earn that trust—not expect it. This means building relationships with communities early, listening to local concerns, and being transparent about both the risks and the benefits. Technologies like Small Modular Reactors (SMRs) may offer improved safety features and smaller footprints, but they still require local buy-in.

A 2024 Gallup poll showed that 61% of Americans support nuclear energy, the highest level since Fukushima. [31] Support is often stronger when people see nuclear energy’s role in reducing carbon emissions and providing reliable power, but even then, acceptance must be earned on a case-by-case basis as NIMBY remains a serious concern. Without that trust, even technically sound projects can face opposition or fail to move forward. Community engagement isn’t a formality—it’s a central part of building a responsible energy future.

6 Evolving Policy

Volatile Policy

The development of Small Modular Reactors (SMRs) must navigate a complex regulatory environment that, while essential for public safety and environmental protection, can introduce challenges related to cost and project timelines. SMRs follow the same core licensing framework as large reactors under the Nuclear Regulatory Commission (NRC), including design certification, combined license (COL) applications, and comprehensive safety and environmental reviews. Although SMRs are designed with features that may reduce the potential impact of accidents—such as smaller reactor cores, passive safety systems, and underground containment—they often rely on technologies not fully addressed in existing regulations. These include non-light water coolants, advanced fuels, and modular construction methods. As a result, many SMR applications require case-by-case evaluation, which can create procedural delays and uncertainty for developers.

Emergency Planning Zones (EPZs) are another area under review. While current rules were built around large-scale reactors, some SMR designs may justify smaller EPZs due to their lower off-site risk potential. However, there is no standardized process yet for scaling these zones, requiring NRC review and approval on a project-by-project basis. Additionally, SMRs remain subject to longstanding rules on spent fuel storage, transportation, and waste disposal, even though they may produce lower waste volumes.

Recognizing these challenges, policymakers are working to modernize the regulatory process. The NRC is currently developing a new licensing framework—10 CFR Part 53—to better accommodate advanced reactor technologies. In parallel, Executive Orders and DOE initiatives have encouraged regulatory streamlining and interagency coordination to support deployment of advanced reactors, particularly in support of national clean energy and resilience goals. While the regulatory process remains necessarily rigorous, these reforms aim to make it more predictable and responsive to the unique characteristics of SMRs.

Incentives

Since the 1950s, nuclear power has received the largest share of U.S. federal investment in energy research and development. According to historical data from 1950 to 2016, nuclear energy accounted for 45% of all federal energy R&D expenditures. This is nearly double the funding allocated to coal (23%), and significantly more than renewables (19%), oil (5%), natural gas (4%), geothermal (3%), and hydro (1%). This sustained level of support reflects long-standing federal interest in nuclear energy’s role in national security, grid reliability, and low-carbon power generation. [32]

The U.S. federal government offers a robust set of incentives to support the deployment of first-of-a-kind (FOAK) Small Modular Reactors (SMRs). Through the Department of Energy (DOE), up to $800 million is available under the 2025 Gen III+ SMR Tier 1 program to support licensing, site development, and early construction efforts for initial projects. An additional $100 million is allocated for Tier 2 efforts that prepare follow-on deployments. The DOE’s Advanced Reactor Demonstration Program (ARDP) also provides significant cost-share funding to help cover engineering and licensing for SMR developers like NuScale and X-Energy. Legislative backing comes from several sources: the Inflation Reduction Act (IRA) offers clean energy tax credits and funding for advanced nuclear fuel like HALEU; the Infrastructure Investment and Jobs Act allocated over $2.4 billion for advanced nuclear, including SMRs and microreactors; and the ADVANCE Act of 2024 requires the NRC to reduce licensing fees, streamline environmental permitting, and offer financial incentives for early adopters. Additional benefits include federal loan guarantees, Price-Anderson liability coverage, and long-term production tax credits, all of which help de-risk investment and reduce the high upfront capital burden that typically challenges FOAK nuclear projects.

<p “>Several U.S. states are offering targeted incentives to attract and support Small Modular Reactor (SMR) development, especially first-of-a-kind (FOAK) projects. Texas has taken a leading role by establishing a $350 million nuclear fund and proposing up to $2 billion in total financing through House Bill 14, along with regulatory streamlining and 24/7 clean energy credit support. Tennessee has committed $350 million through the Tennessee Valley Authority and created a $50 million state fund to support nuclear manufacturing. Indiana has passed legislation enabling utilities to recover SMR development costs and formed a coalition to advance deployment. States like Virginia, Arizona, Arkansas, North Dakota, and Utah have also implemented laws allowing utilities to recover SMR costs and encouraging nuclear within clean energy portfolios. These incentives—ranging from grants and cost-recovery mechanisms to regulatory fast-tracking—are designed to complement federal support and reduce barriers for early SMR projects.Small Modular Reactors (SMRs) have received significant momentum from recent federal legislation and executive actions that improve their financial outlook and development feasibility. Under the Inflation Reduction Act (IRA), SMRs are eligible for both the Investment Tax Credit (ITC) and the Production Tax Credit (PTC). The ITC allows developers to recover up to 30% of project capital costs, with additional bonus credits for domestic content, energy community siting, or meeting labor standards. Alternatively, the PTC offers a per-kilowatt-hour credit for electricity produced over a 10-year period—enhancing cash flow and making long-term operation more economically competitive. The ability to choose between these credits allows developers to optimize their financing strategy based on project scale and output.

Recent policy efforts further strengthen the incentive landscape. The One Big Beautiful Bill Act (OBBBA) reaffirmed full support for the Section 45U nuclear PTC through 2031 and preserved access to the tech-neutral ITC and PTC (Sections 48E and 45Y) for projects commencing before 2029. These provisions provide SMR developers with valuable planning certainty and financial predictability. Additionally, Executive Order 14057 directs federal agencies to prioritize the procurement of carbon-free electricity, including nuclear, by 2030. The order not only encourages deployment of advanced reactors but also calls for expanded support for domestic nuclear fuel infrastructure, with particular emphasis on enabling the commercial availability of High-Assay Low-Enriched Uranium (HALEU)—a critical fuel type for many SMR designs. By coordinating efforts across DOE, NRC, and national labs, EO 14057 aims to reduce U.S. reliance on foreign HALEU sources and accelerate the creation of a secure, domestic fuel supply chain.

Together, these tax incentives, legislative protections, and executive directives establish a strong policy framework that supports SMR deployment, de-risks capital investment, and promotes long-term resilience of the nuclear energy sector.

Other Policy Risks

A key challenge for attracting investment in SMR projects is the potential for extended licensing timelines and unpredictable costs as the Nuclear Regulatory Commission (NRC) is still working to adapt its framework for SMR technologies. Many designs incorporate first-of-a-kind systems—such as non-light water coolants, advanced fuels, and underground containment—that don’t yet fit neatly within existing rules, often requiring detailed case-by-case assessments. These reviews are critical to ensuring public safety, but the absence of established precedents can create uncertainty in project planning and timelines.

Beyond the NRC, SMR deployment can be delayed or halted by multiple agencies. The EPA oversees environmental reviews under NEPA; the Army Corps of Engineers regulates impacts on wetlands and waterways; state utility commissions govern site approvals and power purchase agreements; and local planning boards or tribal authorities may require zoning, cultural, or land-use assessments. These processes serve essential protective functions but can introduce complex coordination and procedural variation, particularly for multi-jurisdictional projects.

Additional risks for SMRs include uncertainty around long-term federal incentives, as continued support through the IRA and ADVANCE Act remains subject to shifting political priorities. Fuel availability is another constraint, with many SMRs relying on High-Assay Low-Enriched Uranium (HALEU), for which a robust commercial supply chain has yet to emerge. Public acceptance and legal opposition can also present hurdles, particularly in communities unfamiliar with nuclear technology or concerned about long-term waste. Meanwhile, global competitors such as China, Russia, and the UK are advancing their SMR fleets under more centralized regulatory environments, adding strategic urgency to U.S. efforts to modernize its oversight without compromising rigor.

7 Cost of Capacity & Energy

SMRs offer firm, dispatchable power and long-duration reliability, even though their economic viability is heavily dependent on regulatory certainty, project standardization, and site-specific development costs. SMRs provide a zero-carbon generation solution capable of continuous output, which makes them especially attractive for large loads such as data centers.

Capital and Operational Expenditures

The major components of CAPEX for SMRs include the reactor modules, cooling infrastructure, containment structure, safety and control systems, fuel handling equipment, and grid interconnection facilities. SMRs benefit from modular construction, enabling off-site fabrication and reduced on-site labor. Based on U.S. DOE-backed project estimates and early commercial deployments, capital costs for SMRs range from $2.47 million/MW to $4.67 million/MW to depending on vendor, design maturity, and site complexity. [33] [34] For a 300 MW SMR, this equates to an installed CAPEX range of $741 million to $1.4 billion.Operations and maintenance (O&M) costs for SMRs are lower overall than those of conventional nuclear plants, primarily due to passive safety systems and standardized, modular designs. Fixed OPEX ranges from $136,000 to $158,000 per MW-year, while variable OPEX typically ranges from $18.50 to $27 per MWh, reflecting efficient fuel use, limited staffing, and reduced waste handling requirements. Fuel costs remain modest, with enriched uranium priced around $0.85/MMBTU and a burn rate of 10.34 MMBTU/MWh, resulting in total fuel-related costs of approximately $12 to $20 per MWh, including $1/MWh for spent fuel storage. These low fuel costs are supported in part by uranium’s high energy density, a mature enrichment market, and federal investment in domestic fuel infrastructure, which helps reduce upstream development costs that would otherwise be passed on to operators. While fuel and waste management do not dominate the cost structure, they remain a meaningful part of overall operating expenses.

Levelized Cost of Capacity and Levelized Cost of Energy

SMRs have the highest Levelized Cost of Capacity (LCOC) among all technologies analyzed, approximately $336,000 to $719,000 per MW-year, requiring them to run at high capacity factors, and making them impractical for emergency or standby applications.

The Levelized Cost of Electricity (LCOE) for SMRs servicing a co-located load could range from $73/MWh with low-end cost and high utilization to $211/MWh at high-end costs and lower utilization without incentives, and depending on financing assumptions, build schedule, and scale. Assuming high utilization and median costs, the LCOE before incentives is $121/MWh.  Since SMR’s are still being developed and there is no historical data, these pricings are estimates of what appears as most likely in the coming years.  Early projects may be on the high end of this range until production lines mature, and installations are streamlined.  CapEx dominates the share of costs as shown in Figure 9.2.  Parameter values supporting these calculations are presented in Table 9.1.

The high capital cost of and high utilization of SMRs make them applicable to either the ITC or PTC incentives, with the ITC showing greater advantage as seen in Figure 9.3.  With the ITC, LCOE reaches $90/MWh.  While this value is higher than other options, it offers reliable, dispatchable power at a price that is protected from volatile fuel prices.

*Incentive numbers reflect the net effect on the project cost.

References

[1] European Nuclear Society, “Fuel Comparison,” European Nuclear Society, 2025. [Online]. Available: https://www.euronuclear.org/glossary/fuel-comparison/. [Accessed 17 June 2025].

[2] S. Cuthrell, “U.S. Pushes $900M for Small Modular Reactors,” IEEE Spectrum, 21 April 2025. [Online]. Available: U.S. Pushes $900M for Small Modular Reactors . [Accessed 16 June 2025].

[3] M. Sutton and M.-B. Kimyata, “Overview of Licensing for Nuclear Reactors & other NRC Licensed Facilities,” U.S. Nuclear Regulatory Commission, Washington D.C., 2024.

[4] World Nuclear News, “Application lodged for construction of Texas SMR Plant,” World Nuclear News, 31 March 2025. [Online]. Available: https://www.world-nuclear-news.org/articles/application-lodged-for-construction-of-texas-smr-plant. [Accessed 20 June 2025].

[5] NuScale Power LLC, “NuScale Power Module,” NuScale Power LLC, 2025. [Online]. Available: https://www.nuscalepower.com/products/nuscale-power-module. [Accessed 20 June 2025].

[6] Office of Nuclear Energy, “X-energy is Developing a Pebble Bed Reactor That They Say Can’t Melt Down,” U.S. Department of Energy, 5 January 2021. [Online]. Available: https://www.energy.gov/ne/articles/x-energy-developing-pebble-bed-reactor-they-say-cant-melt-down. [Accessed 20 June 2025].

[7] Nuclear Power Technology Development Section, “Small Modular Reactor Technology Catalogue 2024 Edition,” International Atomic Energy Agency, Vienna, 2024.

[8] New York Independent System Operator, “Appendix F: Dispatchable Emission-free Resources 2023-2042 System and Resource Outlook,” New York Independent System Operator, 22 July 2022. [Online]. Available: https://www.nyiso.com/documents/20142/46037616/Appendix-F-Dispatchable-Emission-Free%20Resources.pdf/c18e686f-241e-f729-c0fa-ef3c43515bd3. [Accessed 16 June 2025].

[9] Y. Ismail and B. Bromley, “Assessment of Small Modular Ractors for Load-Following Capabilities,” Canadian Nuclear Laboratories, Ontario, 2019.

[10] Electric Reliability Council of Texas, “Inertia: Basic Concepts and Impacts on the ERCOT Grid,” Electric Reliability Council of Texas, 4 April 2018. [Online]. Available: https://www.ercot.com/files/docs/2018/04/04/Inertia_Basic_Concepts_Impacts_On_ERCOT_v0.pdf. [Accessed 16 June 2025].

[11] Donald C. Cook Nuclear Plant, “Donald C. Cook Nuclear Plant Units 1 and 2 Reliability and MTBF Analysis,” Nuclear Regulatory Commission, Bridgman, 1992.

[12] S. Sowers, “EPRI Collaborates with Chinese Nuclear Utility to Transfer Insights from Successful Reliability Program,” Electric Power Research Institute, INC, 9 May 2017. [Online]. Available: https://eprijournal.com/maximizing-reliability-of-instrumentation-and-controls/. [Accessed 16 June 2025].

[13] Westinghouse Nuclear, “Westinghouse Common Q™ Platform,” Westinghouse Electric Company LLC, [Online]. Available: https://westinghousenuclear.com/data-sheet-library/westinghouse-common-q-platform/. [Accessed 16 June 2025].

[14] IAEA Power Reactor Information System, “Energy Availability Factor,” International Atomic Energy Agency, 12 August 2025. [Online]. Available: https://pris.iaea.org/pris/worldstatistics/threeyrsenergyavailabilityfactor.aspx. [Accessed 13 August 2025].

[15] U.S. Department of Energy Office of Nuclear Energy, “NUclear Power is the Most Reliable Energy Source and It’s Not Even Close,” U.S. Department of Energy, 24 March 2021. [Online]. Available: https://www.energy.gov/ne/articles/nuclear-power-most-reliable-energy-source-and-its-not-even-close. [Accessed 16 June 2025].

[16] World Nuclear Association, “How Can Nuclear Combat Climate Change?,” World Nuclear Association, 2018. [Online]. Available: https://world-nuclear.org/nuclear-essentials/how-can-nuclear-combat-climate-change. [Accessed 17 June 2025].

[17] K. Cafferty, T. Vince, D. Davis, C. Bastidas, P. Bhowmik and S. Snyder, “Updated Assessment of Water-Energy Issues for Nuclear Power,” U.S Departemnt of Energy, July 2023. [Online]. Available: https://inldigitallibrary.inl.gov/sites/sti/sti/Sort_66638.pdf. [Accessed 18 June 2025].

[18] B. Kocsis, “Neural network-based prediction of decommissioning costs for SMRs,” Elsevier, Pecs, 2025.

[19] G. Marino, “The World’s Nuclear Fleet is Aging- How Do You Recycle a Nuclear Power Plant?,” Trellis Group Inc., 13 May 2021. [Online]. Available: https://trellis.net/article/worlds-nuclear-fleet-aging-how-do-you-recycle-nuclear-power-plant/. [Accessed 18 June 2025].

[20] World Nuclear Association, “What Is Nuclear Waste, and What Do We Do With It?,” World Nuclear Association, 2025. [Online]. Available: https://world-nuclear.org/nuclear-essentials/what-is-nuclear-waste-and-what-do-we-do-with-it. [Accessed 17 June 2025].

[21] U.S. Government Accountability Office, “Nuclear Waste Disposal,” U.S. Government Accountability Office, 2020. [Online]. Available: https://www.gao.gov/nuclear-waste-disposal. [Accessed 17 June 2025].

[22] Office of Nuclear Energy, “5 Fast Facts about Spent Nuclear Fuel,” U.S. Department of Energy, 3 October 2022. [Online]. Available: https://www.energy.gov/ne/articles/5-fast-facts-about-spent-nuclear-fuel. [Accessed 18 June 2025].

[23] J. Turrentine, “Coal Ash Is Hazardous. Coal Ash Is Waste. But According to the EPA, Coal Ash Is Not “Hazardous Waste.”,” National Resources Defense Council, 6 September 2019. [Online]. Available: https://www.nrdc.org/stories/coal-ash-hazardous-coal-ash-waste-according-epa-coal-ash-not-hazardous-waste. [Accessed 17 June 2025].

[24] E. Derr, “Nuclear Needs Small Amounts of Land to Deliver Big Amounts of Electricty,” Nuclear Energy Institute, 29 April 2022. [Online]. Available: https://www.nei.org/news/2022/nuclear-brings-more-electricity-with-less-land. [Accessed 18 June 2025].

[25] Holtec International, “Frequently Asked Questions,” Holtec International, 2025. [Online]. Available: https://holtecinternational.com/communications-and-outreach/smr/. [Accessed 18 June 2025].

[26] Idaho National Laboratory, “Advanced Small Modular Reactors,” Idaho National Laboratory, August 2024. [Online]. Available: https://inl.gov/trending-topics/small-modular-reactors/. [Accessed 18 June 2025].

[27] NuScale Power LLC, “Understanding Emergency Planning Zones,” NuScale Power LLC, 2025. [Online]. Available: https://www.nuscalepower.com/exploring-smrs/smr-101/understanding-emergency-planning-zones. [Accessed 18 June 2025].

[28] Canadian Nuclear Safety Commission, “About Small Modular Reactors,” Canadian Nuclear Safety Commission, 21 February 2021. [Online]. Available: https://www.cnsc-ccsn.gc.ca/eng/reactors/smr/about/. [Accessed 18 June 2025].

[29] H. Mueller, “Sound Emissions from Nuclear Power Plants,” Gesund.-Ing., Haustech.-Bauphys.-Umwelttech., 6 May 1983. [Online]. Available: inis.iaea.org/records/nywvr-qrw57. [Accessed 18 June 2025].

[30] Nuclear Regulatory Commission, “Catawba Nuclear Station Enviormental Protection Plan Two Unit Ambient Noise Survey,” Nuclear Regulatory Commission, April 1989. [Online]. Available: www.nrc.gov/docs/ML2024/ML20245F495.pdf. [Accessed 18 June 2025].

[31] M. Brenan, “Nuclear Energy Support Near Record High in U.S.,” Gallup Inc, 9 April 2025. [Online]. Available: https://news.gallup.com/poll/659180/nuclear-energy-support-near-record-high.aspx. [Accessed 18 June 2025].

[32] Management Information Services, Inc, “Two Thirds of a Century and $1 Trillion+ U.S. Energy Incentives: Analysis of Federal Expenditures for Energy Development,” The Nuclear Energy Institute, Washington D.C., 2017.

[33] LAZARD , “Levelized Cost of Energy + June 2025,” LAZARD Inc., 16 June 2025. [Online]. Available: https://www.lazard.com/media/eijnqja3/lazards-lcoeplus-june-2025.pdf. [Accessed 20 June 2025].

[34] Nuclear Energy Institute, “SMR Start to a Clean Future: The Economics of Small Modular Reactors,” Nuclear Energy Institute, Washington D.C., 2021.