Nuclear reactor design companies are integral to the evolution of energy solutions, developing innovative reactor concepts that prioritize safety and efficiency. They operate in an industry increasingly focused on technological advancements like Small Modular Reactors (SMRs) and alternative fuels, ushering in a new era of sustainable energy. As nations and organizations push for ambitious carbon-neutral goals, these companies are at the forefront, addressing efficiency concerns and responding to regulatory demands. Their work is pivotal for future energy supplies, highlighting the critical balance between advancements in nuclear technology and public safety.

This list showcases 22 notable nuclear reactor design companies hailing from diverse geographies, including France, the United States, and Argentina. Founded between 1938 and 2021, these companies range in size from small firms with fewer than 50 employees to major players employing over 10,000. Their specializations include reactor safety, engineering, and lifecycle management, with many leading the charge in alternative reactor designs and sustainable practices in the nuclear sector.

Read on to uncover more about the top nuclear reactor design companies.

Top 22 Nuclear Reactor Design Companies

1. Framatome

• Website: framatome.com
• Ownership type: Private
• Headquarters: Courbevoie, Île-De-France, France
• Employee distribution: France 79%, United States (USA) 11%, Germany 5%, Other 5%
• Latest funding: $223.1M, January 2024
• Founded year: 1958
• Headcount: 10001+
• LinkedIn: framatome

Framatome, founded in 1958 and based in Courbevoie, Île-De-France, France, is a prominent player in the nuclear energy sector. The company focuses on providing comprehensive solutions for nuclear power plants, including engineering, manufacturing, and maintenance services. With a workforce of over 12,000 employees, Framatome operates globally, with a significant presence in France, the United States, and Germany. Their expertise covers a wide range of areas, including design and service engineering, component manufacturing, and digital solutions. Framatome is actively involved in the development of advanced technologies, such as accident-tolerant fuel assemblies and digital transformation solutions for critical industries. Recently, they secured funding of approximately €223 million, indicating ongoing investment in their capabilities and future projects. Framatome's commitment to enhancing the safety and efficiency of nuclear operations underscores their vital role in the energy sector.

2. Atkins

• Website: atkinsglobal.com
• Ownership type: Corporate
• Headquarters: New Zealand
• Employee distribution: United Kingdom (UK) 48%, India 21%, United States (USA) 14%, Other 17%
• Latest funding: $3.6B, April 2017
• Founded year: 1938
• Headcount: 10001+
• LinkedIn: atkins

AtkinsRéalis is an engineering and consulting firm founded in 1938, with a workforce of over 11,000 employees. The company operates across various sectors, including transportation, energy, and infrastructure. In the nuclear sector, Atkins provides essential services such as nuclear reactor support, life extension, and environmental remediation. Their expertise helps clients navigate complex engineering challenges while promoting sustainable solutions. With a significant presence in the UK, India, and the USA, Atkins is well-positioned to address the needs of the global nuclear industry. Their commitment to engineering a better future is evident in their focus on modernizing nuclear systems as part of a fossil-free future.

3. Edvance

• Website: edvance.fr
• Ownership type: Private
• Headquarters: Montrouge, Île-De-France, France
• Employee distribution: France 86%, United Kingdom (UK) 11%, Germany 2%
• Founded year: 2017
• Headcount: 1001-5000
• LinkedIn: edvance.fr

Edvance, founded in 2017 and based in Montrouge, Île-De-France, is a private nuclear engineering company that specializes in the design, procurement, construction, and commissioning of nuclear islands for EPR reactors. With approximately 1,877 employees, Edvance operates primarily in France, the UK, and Germany. The company plays a crucial role in several high-profile nuclear projects, including Flamanville 3, Hinkley Point C, and Sizewell C, where they are responsible for engineering and managing contracts related to the nuclear island. Edvance aims to contribute to a low-carbon future by developing safe and efficient nuclear power solutions, making it a significant player in the nuclear energy sector.

4. Cavendish Nuclear

• Website: cavendishnuclear.com
• Ownership type: Private
• Headquarters: Birchwood, England, United Kingdom (UK)
• Employee distribution: United Kingdom (UK) 100%
• Founded year: 2000
• Headcount: 5001-10000
• LinkedIn: cavendish-nuclear

Cavendish Nuclear, founded in 2000 and based in Birchwood, England, is a prominent nuclear services provider. The company specializes in engineering and consultancy across the Clean Energy, Defence, and Civil Decommissioning sectors. With a workforce of around 5,000 employees, Cavendish Nuclear plays a crucial role in managing complex nuclear operations and supporting critical infrastructure projects. Their services include nuclear infrastructure design and build, nuclear equipment design and manufacture, and decommissioning and waste management. Notably, Cavendish Nuclear is involved in the operation of EDF Energy's nuclear reactor fleet and is part of the MEH Alliance at Hinkley Point C, contributing to the UK's nuclear power landscape. Their commitment to safety and compliance is evident in their extensive experience and technical capabilities, making them a key player in the nuclear industry.

5. 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 that specializes in advanced nuclear energy solutions. The company designs and engineers small modular reactors, notably the Xe-100, which is recognized for its safety and efficiency. X-energy also develops mobile reactors like the Xe-Mobile, aimed at providing power to remote locations and critical infrastructure. Their proprietary TRISO-X fuel is engineered to withstand extreme conditions, enhancing the safety and reliability of their reactors. With a workforce of approximately 869 employees, X-energy is actively involved in the nuclear industry, focusing on sustainable energy solutions for utilities and industries. The company has received attention for its innovative approaches and has been awarded significant contracts, including a recent investment tax credit for its TRISO-X fuel fabrication facility.

6. 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 is an innovative energy company based in Charlotte, North Carolina, specializing in advanced nuclear reactor technology. Founded in 2013, the company is dedicated to providing carbon-free energy solutions tailored for industrial clients seeking sustainable alternatives. Terrestrial Energy is particularly known for its Integral Molten Salt Reactor (IMSR), which represents a significant advancement in nuclear technology. The company emphasizes research and development to meet the increasing global demand for clean energy. With a workforce primarily located in Canada, Terrestrial Energy has established itself as a key player in the nuclear sector, actively pursuing partnerships and projects that enhance its technological capabilities and market presence.

7. TechnicAtome

• Website: technicatome.com
• Ownership type: Corporate
• Headquarters: France
• Employee distribution: France 100%
• Latest funding: October 2024
• Founded year: 1972
• Headcount: 1001-5000
• LinkedIn: technicatome

TechnicAtome is a French nuclear engineering company founded in 1972, with a workforce of approximately 2,000 employees. The company specializes in the design, construction, and maintenance of compact nuclear reactors, primarily serving clients in the defense and research sectors. TechnicAtome's expertise extends to operational support and engineering services for naval propulsion and nuclear installations. They have been involved in significant projects, including the development of Small Modular Reactors (SMR) and the Jules Horowitz Reactor, which are pivotal in advancing nuclear technology. The company also provides high-value services related to the operation and maintenance of nuclear systems, ensuring safety and efficiency. TechnicAtome's commitment to innovation and quality positions it as a key player in the nuclear engineering field.

8. Invap

• Website: invap.com.ar
• Ownership type: Private
• Headquarters: San Carlos De Bariloche, Río Negro, Argentina
• Employee distribution: Argentina 97%, Other 3%
• Founded year: 1976
• Headcount: 1001-5000
• LinkedIn: invap

Invap, based in San Carlos De Bariloche, Argentina, is a private technology company founded in 1976. With a workforce of approximately 1,600 professionals, Invap specializes in the design and construction of complex technological systems across several sectors, including nuclear, aerospace, and medical. In the nuclear sector, Invap has established itself as a key player, developing research reactors and facilities for radioisotope production. Their projects span over ten countries, showcasing their capability to meet the specific needs of various clients. Invap's focus on safety and efficiency in nuclear technology is reflected in their comprehensive services, which include engineering for nuclear power plants and waste management solutions. The company is recognized for its innovative approach and has been involved in significant projects like the RA-10 reactor, which is pivotal for Argentina's nuclear research and development.

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 is a private nuclear energy company based in Alameda, California, founded in 2016. The firm specializes in the development of advanced reactor technology, particularly small modular reactors (SMRs), aimed at providing sustainable power generation. With operations extending across California, New Mexico, and Tennessee, Kairos Power is dedicated to transforming the energy sector through innovative engineering and research. The company is currently focused on its fluoride salt-cooled high-temperature reactor (KP-FHR), which is designed to be cost-competitive with natural gas while ensuring high availability and low maintenance costs. Kairos Power has received significant funding, including a recent grant of up to $303 million from the U.S. Department of Energy to support its advanced reactor demonstration program. This funding underscores their commitment to advancing nuclear technology and their role in the clean energy transition.

10. OJSC Nikiet

• Website: nikiet.ru
• Ownership type: Private
• Headquarters: Moscow, Moscow, Russia
• Employee distribution: Russia 100%
• Founded year: 2009
• Headcount: 11-50
• LinkedIn: ojsc-nikiet

OJSC Nikiet, based in Moscow, Russia, is a private nuclear engineering firm founded in 2009. The company specializes in the development of advanced reactor technologies and conducts scientific research within the nuclear sector. Nikiet provides solutions tailored for nuclear power plants and research institutions, emphasizing improvements in safety and efficiency in nuclear energy production. The firm is actively involved in the design and construction of various reactor types, including those for regional energy needs and research purposes. Notably, Nikiet is contributing to the international ITER project, focusing on the development of high-tech components for this groundbreaking fusion reactor. With a dedicated team of 25 employees, Nikiet is positioned as a key player in the nuclear engineering field, particularly in Russia.

11. MHC Gruppe

• Website: mhc-gruppe.de
• Ownership type: Private
• Headquarters: Germersheim, Rhineland-Palatinate, Germany
• Employee distribution: Germany 100%
• Founded year: 1998
• Headcount: 501-1000
• LinkedIn: mhc-gruppe

MHC Gruppe, based in Germersheim, Germany, is an engineering firm established in 1998. The company operates primarily in energy technology, automation solutions, and nuclear technology. MHC Gruppe provides a comprehensive suite of services that includes project planning, construction, and maintenance for nuclear facilities. Their expertise extends to system engineering and the decommissioning of nuclear plants, showcasing their capability in managing the lifecycle of nuclear installations. The firm serves a variety of clients, including energy providers and industrial entities, emphasizing quality and reliability in their operations. With a workforce of around 500 employees, MHC Gruppe is committed to delivering tailored solutions that meet the specific needs of their clients in the energy sector.

12. 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 private 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), which is designed to recycle nuclear waste and produce clean energy. Moltex Energy is focused on providing sustainable energy solutions that address climate change while meeting the growing energy demands of the future. The company has received funding, including a grant of approximately $792,267 in March 2021, which supports its ongoing research and development efforts. Currently, Moltex is working towards licensing and constructing its first reactor in New Brunswick, Canada, with plans to expand its technology to a global market that is increasingly looking for clean energy alternatives.

13. 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 private technology company that specializes in the energy sector, particularly nuclear power. Founded in 1986, Holtec has grown to employ over 1,000 professionals across various locations, with a significant presence in the United States and India. The company offers a wide range of products and services, including spent nuclear fuel management, decommissioning, and heat transfer equipment. Holtec's clients primarily include nuclear power plants and energy companies that rely on their expertise for safe and efficient operations. Notably, Holtec is actively developing the SMR-300, a small modular reactor designed to enhance safety and economic viability in nuclear energy production. The company has also secured substantial funding, with a recent debt funding amounting to $1.52 billion in March 2024, indicating strong financial backing for their ongoing projects and innovations.

14. KURY Ingénierie

• Website: kury.fr
• Ownership type: Private
• Headquarters: Clamart, Île-De-France, France
• Employee distribution: France 100%
• Founded year: 2000
• Headcount: 51-200
• LinkedIn: kury-ing%c3%a9nierie

KURY Ingénierie, founded in 2000 and based in Clamart, Île-De-France, is a private engineering consulting firm that specializes in the energy sector, particularly nuclear power. With a workforce of approximately 50 employees, the company provides a range of services including system design, safety assessments, and project management. KURY Ingénierie is dedicated to assisting energy companies in achieving operational efficiency and adhering to stringent safety standards. Their expertise extends to conducting feasibility studies for control systems in nuclear plants, developing safety reports, and designing various technical systems essential for nuclear operations. The firm is ISO 9001 certified, underscoring its commitment to quality in system design and project execution. KURY Ingénierie also emphasizes the continuous development of its engineers through internal training programs, ensuring that their team remains knowledgeable and skilled in the latest industry practices.

15. 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, based in Seattle, Washington, is a nuclear energy company founded in 2011. The firm specializes in advanced reactor technologies and fuel solutions, particularly through its Micro Modular Reactor (MMR) and TRISO particle fuels. Ultra Safe Nuclear aims to provide reliable, zero-carbon energy to industrial clients and research institutions, contributing to global decarbonization efforts. The company has an active project pipeline, with several MMR installations planned or underway in locations such as Poland, Finland, and Canada. Their recent funding, including a grant awarded in June 2023, supports their ongoing development and deployment of innovative nuclear technologies. With a workforce of approximately 42 employees, Ultra Safe Nuclear is positioned to make significant strides in the nuclear energy sector, focusing on safety, efficiency, and environmental sustainability.

16. newcleo

• Website: newcleo.com
• Ownership type: Venture Capital
• Headquarters: Paris, Île-De-France, France
• Employee distribution: France 44%, Italy 35%, United Kingdom (UK) 20%
• Latest funding: Series A, $150.3M, September 2024
• Founded year: 2021
• Headcount: 501-1000
• LinkedIn: newcleo

newcleo is a nuclear engineering firm based in Paris, France, founded in 2021. The company specializes in the development of Lead Fast Reactor (LFR) technology, which is a promising approach to nuclear energy that emphasizes safety and efficiency. newcleo provides engineering services tailored to the energy sector, focusing on reactor design and material analysis. With a workforce of approximately 683 employees, the company operates primarily in France, Italy, and the United Kingdom. In September 2024, newcleo secured a Series A funding round amounting to over 150 million euros, reflecting strong investor interest in their innovative solutions for nuclear power systems. Their work includes mechanical design activities and experimental facilities, particularly in the context of small modular nuclear reactors (SMRs).

17. EAG (Empresarios Agrupados - GHESA)

• Website: empresariosagrupados.es
• Ownership type: Private
• Headquarters: Madrid, Madrid, Spain
• Employee distribution: Spain 94%, France 2%, Other 3%
• Founded year: 1963
• Headcount: 1001-5000
• LinkedIn: empresarios-agrupados-ghesa

Empresarios Agrupados (EAG), founded in 1963 and based in Madrid, Spain, is a private engineering and construction firm specializing in power generation projects. With a workforce of over 1,000 employees, EAG has built a solid reputation in the energy sector, particularly in nuclear, conventional, and renewable energy solutions. The company provides a wide array of services, including engineering, construction, project management, and operational support for nuclear power plants. EAG's nuclear business unit focuses on new-build plants, operational support for existing facilities, and decommissioning, spent fuel, and radioactive waste management. They are also involved in advanced projects related to nuclear fission and fusion, showcasing their commitment to innovation in the nuclear field. EAG has worked with major international clients and has been involved in projects across more than 80 countries, demonstrating their global reach and expertise in the energy sector.

18. 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, aiming to provide sustainable energy solutions that address the growing demand for cleaner energy sources. Flibe Energy's innovative technologies focus on enhancing safety and efficiency in nuclear energy production. The company is actively involved in research and development, collaborating with organizations such as the Savannah River National Laboratory to advance nuclear fuel cycle technologies. Their reactor designs, particularly the Lithium Fluoride Thorium Reactor (LFTR) and the Lithium Fluoride Low Enriched Uranium Reactor (LFLEUR), are designed to optimize energy production while minimizing waste. Flibe Energy's commitment to a sustainable nuclear future is evident in their ongoing projects and partnerships, which aim to integrate nuclear technology into various applications beyond electricity generation.

19. Laurentis Energy Partners

• Website: laurentisenergy.com
• Ownership type: Private
• Headquarters: Toronto, Ontario, Canada
• Employee distribution: Canada 99%, Other 1%
• Founded year: 2012
• Headcount: 201-500
• LinkedIn: laurentis-energy-partners

Laurentis Energy Partners, based in Toronto, Ontario, is a private nuclear energy company founded in 2012. The firm specializes in isotope production, nuclear lifecycle services, and engineering solutions tailored for new nuclear projects. With a workforce of approximately 160 employees, Laurentis serves utilities and industrial clients seeking sustainable energy solutions. Their expertise extends to the development of Small Modular Reactors (SMRs) and large-scale nuclear facilities, showcasing their role in advancing nuclear technology. Laurentis has also made significant contributions to isotope production, being recognized for innovative techniques that enhance the efficiency and safety of nuclear operations. Their commitment to environmental sustainability and corporate citizenship further underscores their relevance in the nuclear energy sector.

20. Fermi Solutions

• Website: fermisolutions.com
• Ownership type: Private
• Headquarters: Port Elgin, Ontario, Canada
• Employee distribution: Canada 100%
• Founded year: 2020
• Headcount: 11-50
• LinkedIn: fermi-solutions

Fermi Solutions is an engineering consulting firm based in Port Elgin, Ontario, Canada, founded in 2020. The company specializes in the nuclear sector, offering a wide array of services that include engineering design, field engineering, and technical training tailored for nuclear utilities. Their expertise is particularly focused on CANDU systems, and they provide comprehensive project lifecycle engineering solutions, guiding projects from conception to completion. Fermi Solutions is committed to enhancing operational efficiency and safety within the nuclear industry, addressing the growing demand for modernization and innovative solutions. Their project portfolio highlights significant contributions to reactor tooling, nuclear operations, and specialty engineering projects, showcasing their capability to tackle complex engineering challenges. The management team comprises experienced professionals with extensive backgrounds in nuclear safety analysis, design engineering, and project management, further solidifying their position in the industry.

21. Kinectrics

• Website: kinectrics.com
• Ownership type: Corporate
• Headquarters: Toronto, Ontario, Canada
• Employee distribution: Canada 84%, United States (USA) 10%, United Kingdom (UK) 3%, Other 3%
• Latest funding: Other (Grant), $126,000, October 2024
• Founded year: 1912
• Headcount: 1001-5000
• LinkedIn: kinectrics

Kinectrics, based in Toronto, Ontario, has been a significant player in the energy sector since its founding in 1912. With a workforce of around 1,200 employees, the company specializes in engineering, testing, and inspection services across the electricity lifecycle, with a notable emphasis on nuclear energy. Kinectrics supports utilities and nuclear operators by providing solutions that enhance compliance, safety, and operational efficiency. Their capabilities include nuclear engineering and design, particularly for small modular reactors (SMRs) and advanced reactor technologies. The company also engages in decommissioning planning and waste management, ensuring that they address the full spectrum of nuclear lifecycle challenges. Kinectrics has recently received funding, indicating ongoing investment in their capabilities and services.

22. Atomenergomash Group

• Website: aem-group.ru
• Ownership type: Private
• Headquarters: Moscow, Moscow, Russia
• Employee distribution: Russia 100%
• Founded year: 2006
• Headcount: 10001+
• LinkedIn: atomenergomash-group

Atomenergomash Group, based in Moscow, Russia, is a private engineering and manufacturing company established in 2006. It specializes in producing equipment for nuclear and thermal energy generation, as well as water treatment solutions. The company serves energy producers and industrial clients, providing essential technologies and services to ensure efficient and safe operations. Atomenergomash is a key player in the nuclear sector, responsible for the design and production of critical reactor components, including those for VVER reactors, which are prevalent in Russian nuclear power plants. The company also engages in scientific research and development, contributing to advancements in nuclear technology. With a workforce of over 10,000 employees, Atomenergomash operates entirely within Russia, reflecting its focus on the domestic energy market.

Nuclear Reactor Design Insights: Key Companies

Want to Find More Nuclear Reactor Design Companies?

With Inven you'll also get to know the company's:

• Detailed Ownership: Who owns the company? Is it a public or private company? What is the ownership structure?
• Contact data: Who are the founders and CEO's? What are their emails and phone numbers?
• Financials: How do these companies perform financially? What are their revenues and profit margins?

...and a lot more!