Nuclear energy is a pivotal sector in the U.S., generating carbon-free electricity for millions. Companies in this field range from established utilities managing power plants to innovative startups developing advanced reactor technologies. These firms are crucial in addressing climate change by providing clean alternatives to fossil fuels. As the industry shifts toward more sustainable practices, there’s a growing focus on safety, efficiency, and minimizing waste. Notably, small modular reactors (SMRs) and new fuel technologies are paving the way for future energy solutions while creating jobs and stimulating local economies. Innovation continues to be at the core of progress in nuclear energy.

The list features 16 notable nuclear energy companies located throughout the United States, varying in size from small startups to larger corporations. Companies like Holtec International and Southern Nuclear dominate with extensive histories and significant employee counts, while newer entries such as Aalo Atomics inject fresh ideas into the sector. Founded between 1957 and 2023, these firms excel in various niches, including reactor design, nuclear fuel production, safe waste management, and efficient electricity generation. Headquartered in states such as Florida, California, and Alabama, they reflect the wide geographical engagement in advancing nuclear technology.

Read on to discover the top nuclear energy companies in the US.

Top 16 Nuclear Energy Companies in the US

1. Holtec International

• Website: holtecinternational.com
• Ownership type: Private
• Headquarters: Jupiter, Florida, United States (USA)
• Employee distribution: United States (USA) 88%, India 7%, Other 5%
• Latest funding: Other (Debt), $1.5B, March 2024
• Founded year: 1986
• Headcount: 501-1000
• LinkedIn: holtec-international

Holtec International, based in Jupiter, Florida, is a technology company that has been active in the energy sector since its founding in 1986. The company specializes in nuclear power, offering a wide array of products and services that include spent nuclear fuel management, decommissioning, and heat transfer equipment. Holtec's clientele primarily consists of nuclear power plants and energy companies that rely on their expertise for safe and efficient operations. The company is recognized for its innovative approach, particularly with the development of the SMR-300, a small modular reactor designed to enhance safety and efficiency in nuclear energy generation. Holtec also operates Holtec Decommissioning International, which focuses on the safe and efficient decommissioning of shuttered nuclear facilities. With a workforce of over 1,000 employees and a significant presence in the U.S. and India, Holtec continues to expand its influence in the nuclear energy sector. Recently, the company secured $1.52 billion in funding, underscoring its ongoing commitment to growth and innovation in the industry.

2. Terrestrial Energy

• Website: terrestrialenergy.com
• Ownership type: Venture Capital
• Headquarters: Charlotte, North Carolina, United States (USA)
• Employee distribution: Canada 97%, United States (USA) 3%
• Latest funding: October 2022
• Founded year: 2013
• Headcount: 51-200
• LinkedIn: terrestrial-energy-inc

Terrestrial Energy, established in 2013 and based in Charlotte, North Carolina, is an energy company that specializes in advanced nuclear reactor technology. The firm is dedicated to developing carbon-free energy solutions tailored for industrial clients seeking sustainable alternatives. Their flagship technology, the Integral Molten Salt Reactor (IMSR), represents a significant advancement in nuclear energy, focusing on safety, efficiency, and versatility. With a workforce of approximately 67 employees, the company has a strong presence in Canada, where the majority of its operations are based. Terrestrial Energy is actively involved in research and development initiatives, collaborating with various partners to enhance the deployment of its technologies. The company has also been recognized for its innovative approaches, including being listed among Bill Gates' top 10 breakthrough technologies in 2019. Their ongoing projects and partnerships reflect a commitment to addressing the increasing demand for clean energy solutions in the industrial sector.

3. X-energy

• Website: x-energy.com
• Ownership type: Venture Capital
• Headquarters: Rockville, Maryland, United States (USA)
• Employee distribution: United States (USA) 99%, Other 1%
• Latest funding: March 2025
• Founded year: 2009
• Headcount: 201-500
• LinkedIn: x-energy-llc

X-energy, founded in 2009 and based in Rockville, Maryland, is a nuclear reactor manufacturer specializing in advanced nuclear energy solutions. The company designs and engineers small modular reactors, such as the Xe-100, which is recognized for its safety and efficiency. Additionally, X-energy has developed the Xe-Mobile, a mobile reactor designed for remote locations and micro-grids, showcasing their commitment to innovative energy solutions. Their proprietary TRISO-X fuel is engineered to withstand extreme conditions, further enhancing the safety and reliability of their reactors. X-energy's clientele includes utilities and industries seeking sustainable energy solutions to meet increasing demands. With a workforce of approximately 869 employees, the company is actively engaged in advancing nuclear technology and has received attention for its initiatives, including a significant investment tax credit for its TRISO-X fuel fabrication facility.

4. Southern Nuclear

• Website: southernnuclear.com
• Ownership type: Private
• Headquarters: Birmingham, Alabama, United States (USA)
• Employee distribution: United States (USA) 100%
• Founded year: 1990
• Headcount: 1001-5000
• LinkedIn: southernnuclear

Southern Nuclear Operating Company, Inc. is a prominent player in the nuclear energy sector, based in Birmingham, Alabama. Founded in 1990, the company operates eight nuclear energy units across three plants: the Joseph M. Farley Nuclear Plant in Alabama, the Edwin I. Hatch Nuclear Plant in Georgia, and the Alvin W. Vogtle Electric Generating Plant in Georgia. Southern Nuclear is dedicated to generating carbon-free electricity, serving utility companies and various organizations that rely on a stable power supply. The company emphasizes safety and reliability in its operations, adhering to stringent federal standards. Recently, Southern Nuclear achieved a significant milestone by bringing Vogtle Units 3 and 4 into commercial operation, marking a historic moment for the nuclear industry in the U.S. Their commitment to community engagement and innovation in nuclear technology further solidifies their role in the energy sector.

5. STP Nuclear Operating Company

• Website: stpnoc.com
• Ownership type: Private
• Headquarters: Wadsworth, Texas, United States (USA)
• Employee distribution: United States (USA) 100%
• Founded year: 1988
• Headcount: 1001-5000
• LinkedIn: stp-nuclear-operating-company

STP Nuclear Operating Company, founded in 1988, operates the South Texas Project Electric Generating Station located in Wadsworth, Texas. This facility is one of the newest and largest nuclear power plants in the United States, generating 2,700 megawatts of carbon-free electricity. The company plays a crucial role in providing clean energy to around two million homes in Texas. STP Nuclear Operating Company is dedicated to maintaining high safety standards and operational reliability, which is reflected in their recognition as one of America's safest companies. They have also received accolades for their commitment to safe and economical operations from the American Nuclear Society. The company is privately owned and employs approximately 1,263 individuals, focusing on community engagement and environmental sustainability. STP Nuclear Operating Company is a key player in the local energy sector, contributing significantly to the reduction of greenhouse gas emissions through its nuclear power generation.

6. Progress Energy

• Website: progress-energy.com
• Ownership type: Corporate
• Headquarters: Raleigh, North Carolina, United States (USA)
• Employee distribution: United States (USA) 98%, Other 2%
• Latest funding: January 2011
• Founded year: 1908
• Headcount: 10001+
• LinkedIn: progress-energy

Progress Energy, founded in 1908 and based in Raleigh, North Carolina, is an energy company that specializes in electricity generation and distribution. The company operates nuclear power plants and serves approximately 3.1 million customers across the Carolinas and Florida. Progress Energy plays a crucial role in providing essential power services to both residential and business clients. With a workforce of over 10,000 employees, the company is committed to energy efficiency and community engagement. As part of its operations, Progress Energy focuses on maintaining and enhancing its nuclear facilities, ensuring safety and reliability in power generation.

7. Moltex Energy

• Website: moltexenergy.com
• Ownership type: Private
• Headquarters: United States (USA)
• Latest funding: Other (Grant), $792,000, March 2021
• Founded year: 2014
• Headcount: 11-50
• LinkedIn: moltex-energy-llp

Moltex Energy Canada Inc. is a nuclear energy company founded in 2014, based in the United States. The firm is dedicated to developing innovative reactor technologies, particularly the Stable Salt Reactor – Wasteburner (SSR-W). This reactor design aims to utilize recycled nuclear waste as fuel, thereby addressing both energy production and waste management issues. Moltex Energy is currently navigating the approval processes in Canada for its first reactor, which is intended to be built for NB Power in New Brunswick. The company has received funding through grants, with the last reported amount being approximately $792,267 in March 2021. Their technology not only promises to deliver clean energy but also seeks to reduce costs compared to traditional coal or gas energy sources. By integrating waste recycling processes, Moltex Energy is positioning itself as a significant contributor to sustainable energy solutions.

8. Flibe Energy

• Website: flibe-energy.com
• Ownership type: Private
• Headquarters: Huntsville, Alabama, United States (USA)
• Employee distribution: United States (USA) 100%
• Founded year: 2011
• Headcount: 11-50
• LinkedIn: flibe-energy

Flibe Energy, Inc., based in Huntsville, Alabama, is a private nuclear energy company established in 2011. The firm specializes in the development of advanced thorium fueled molten salt reactors, which are designed to offer sustainable energy solutions. Flibe Energy's technology focuses on the benefits of thorium as a fuel source, emphasizing safety, efficiency, and reduced waste production compared to traditional nuclear reactors. The company is committed to revolutionizing energy production and has been involved in various collaborations to enhance its research and development capabilities. Notably, Flibe Energy has partnered with the Savannah River National Laboratory to strengthen nuclear energy fuel cycle research and development. Their innovative reactor designs, including the Lithium Fluoride Thorium Reactor (LFTR), aim to provide scalable and clean energy alternatives, making them a significant player in the nuclear energy sector.

9. Kairos Power

• Website: kairospower.com
• Ownership type: Private
• Headquarters: Alameda, California, United States (USA)
• Employee distribution: United States (USA) 100%
• Latest funding: Other (Grant), $16,000, June 2022
• Founded year: 2016
• Headcount: 201-500
• LinkedIn: kairospower

Kairos Power, established in 2016 and based in Alameda, California, is a private nuclear energy company dedicated to developing advanced reactor technology. The company specializes in small modular reactors (SMRs), particularly its fluoride salt-cooled high-temperature reactor (KP-FHR). This innovative reactor design aims to deliver clean, reliable, and affordable energy solutions, addressing the growing demand for sustainable power generation. Kairos Power operates in multiple states, including California, New Mexico, and Tennessee, where it is building a research and development center and a demonstration reactor. The company has made significant strides in the industry, recently receiving a construction permit from the Nuclear Regulatory Commission for its Hermes demonstration reactor and securing up to $303 million in funding from the U.S. Department of Energy to support its projects. With a focus on safety, efficiency, and cost-effectiveness, Kairos Power is positioned to play a crucial role in the future of nuclear energy.

10. BHI Energy

• Website: bhienergy.com
• Ownership type: Corporate
• Headquarters: Weymouth, Massachusetts, United States (USA)
• Employee distribution: United States (USA) 99%
• Latest funding: April 2022
• Founded year: 1979
• Headcount: 5001-10000
• LinkedIn: bhi-energy

BHI Energy, founded in 1979 and based in Weymouth, Massachusetts, is an energy services company that specializes in maintenance, engineering, and construction across various sectors, including nuclear energy. With a workforce of approximately 1,587 employees, BHI Energy serves utilities, wind developers, and industrial facilities, focusing on operational efficiency and safety. Their nuclear services include maintenance and modification, instrumentation and control (I&C), welding, valve services, and radiological support. They also provide decommissioning services and advanced technologies to enhance operational safety. Recently, BHI Energy was acquired by Westinghouse Electric Company, which has further solidified its position in the nuclear sector, allowing them to leverage Westinghouse's extensive resources and expertise. This acquisition marks a significant step in their commitment to supporting the nuclear industry.

11. Nuclear Fuel Services

• Website: nuclearfuelservices.com
• Ownership type: Corporate
• Headquarters: Erwin, Tennessee, United States (USA)
• Employee distribution: United States (USA) 100%
• Latest funding: August 2008
• Founded year: 1957
• Headcount: 501-1000
• LinkedIn: nuclear-fuel-services

Nuclear Fuel Services, based in Erwin, Tennessee, is a corporate entity under the umbrella of BWX Technologies, Inc. Founded in 1957, the company has established itself as a key player in the nuclear energy sector. It specializes in the production and supply of nuclear fuel, particularly for commercial nuclear reactors. Nuclear Fuel Services is dedicated to ensuring the safe and effective delivery of nuclear solutions, catering to both government and private sector clients. The company operates with a strong emphasis on safety and innovation, reflecting the industry's evolving demands. With a workforce of approximately 395 employees, Nuclear Fuel Services is well-positioned to meet the challenges of the nuclear energy market, contributing to the overall efficiency and reliability of nuclear power generation.

12. Ultra Safe Nuclear

• Website: usnc.com
• Ownership type: Venture Capital
• Headquarters: Seattle, Washington, United States (USA)
• Employee distribution: United States (USA) 42%, South Africa 19%, Canada 14%, Other 26%
• Latest funding: Other (Grant), $150,000, June 2023
• Founded year: 2011
• Headcount: 201-500
• LinkedIn: usnc

Ultra Safe Nuclear Corporation, founded in 2011 and based in Seattle, Washington, specializes in advanced nuclear reactor technologies and fuel solutions. The company is known for its Micro Modular Reactor (MMR) and TRISO particle fuels, which are designed to provide reliable, zero-carbon energy. Ultra Safe Nuclear aims to support decarbonization efforts across various sectors, making their technology particularly relevant in today's energy landscape. They have established a project pipeline that includes collaborations with industrial clients and research institutions in multiple countries, such as Poland, Finland, and Canada. The company has also received funding, including a grant in June 2023, to further its initiatives. With a workforce of around 42 employees and a growing presence in the nuclear energy market, Ultra Safe Nuclear is positioned to contribute significantly to the industry's evolution.

13. Ip3

• Website: ip3international.com
• Ownership type: Private
• Headquarters: Mclean, Virginia, United States (USA)
• Employee distribution: Malaysia 33%, Peru 33%, United States (USA) 33%
• Founded year: 2016
• Headcount: 11-50
• LinkedIn: ip3-corporation

IP3 Corporation, founded in 2016 and based in McLean, Virginia, is a private consulting and energy development company that specializes in nuclear power and security infrastructure. The firm provides a range of services, including nuclear energy project development, energy security consulting, and flexible financing solutions tailored to the needs of host nations. IP3 aims to facilitate the planning, development, financing, and operation of new nuclear energy projects, particularly in regions where there is a strong intent to adopt nuclear power generation. Their work is supported by their subsidiary, Allied Nuclear Partners, which collaborates with a network of respected companies and executives in the nuclear sector. IP3's mission is to create stable and prosperous environments through sustainable energy and security infrastructure, emphasizing the importance of nuclear energy in achieving these goals. They have also engaged in various initiatives, such as partnerships for clean energy projects and discussions on national security related to advanced nuclear reactors, further solidifying their role in the industry.

14. Susquehanna Nuclear

• Website: susquehannanuclear.com
• Ownership type: Private Equity
• Headquarters: Berwick, Pennsylvania, United States (USA)
• Latest funding: June 2016
• Founded year: 1973
• Headcount: 1001-5000
• LinkedIn: susquehanna-nuclear

Susquehanna Nuclear, LLC, based in Berwick, Pennsylvania, operates the Susquehanna Steam Electric Station, a nuclear power generation facility that provides carbon-free electricity to residential and commercial customers. Founded in 1973, the company is a private equity entity and employs around 900 individuals, with additional staff during scheduled outages. The plant features dual unit boiling water reactors with a total capacity of approximately 2,500 MW, enough to power over two million homes. Susquehanna Nuclear emphasizes safety and reliability, consistently achieving high performance ratings in the industry. The company is also dedicated to community support, contributing over $3.5 million to the United Way since 2006 and providing annual donations to local first responders. As a division of Talen Energy, Susquehanna Nuclear plays a crucial role in the nuclear energy sector, focusing on operational excellence and community engagement.

15. Last Energy

• Website: lastenergy.com
• Ownership type: Venture Capital
• Headquarters: Washington, D.C., District Of Columbia, United States (USA)
• Employee distribution: United States (USA) 88%, United Kingdom (UK) 5%, Turkey 3%, Other 3%
• Latest funding: Series B, $40.0M, August 2024
• Founded year: 2019
• Headcount: 51-200
• LinkedIn: lastenergy

Last Energy is an energy company based in Washington, D.C., specializing in nuclear energy solutions. Founded in 2019, the company aims to decarbonize energy production by providing the PWR-20 nuclear power plant, which generates 20 megawatts of electricity and thermal energy for industrial customers. Their focus is on delivering reliable and affordable power to energy-intensive industries, such as data centers and manufacturing. Last Energy operates through a full-service delivery model, managing everything from design to operations. The company has recently secured $40 million in Series B funding, which underscores its potential for growth and innovation in the nuclear sector. With a commitment to using proven reactor technology and a modular approach, Last Energy is positioned to play a significant role in the future of clean energy.

16. Aalo Atomics

• Website: aalo.com
• Ownership type: Venture Capital
• Headquarters: Austin, Texas, United States (USA)
• Employee distribution: United States (USA) 100%
• Latest funding: Series A, $29.4M, August 2024
• Founded year: 2023
• Headcount: 11-50
• LinkedIn: aalo-atomics

Aalo Atomics, based in Austin, Texas, is a nuclear energy company founded in 2023. The firm specializes in the development and commercialization of advanced nuclear reactors, with a focus on the Aalo-1 reactor. This reactor is designed to provide sustainable and reliable energy solutions tailored for utility companies and energy providers. Aalo Atomics is actively pursuing partnerships and investment opportunities to advance its nuclear technology. Recently, the company signed a memorandum of understanding with Idaho Falls Power to deploy a fleet of seven Aalo-1 reactors, marking a significant step in their operational plans. They have also entered the pre-licensing phase with the U.S. Nuclear Regulatory Commission, a crucial milestone for regulatory approval. With a total funding of $33 million, including a $27 million Series A round, Aalo Atomics is positioned to make a notable impact in the nuclear energy sector.

Nuclear Energy Insights: Key Companies in the US

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