Sizewell C competitors and alternatives
As of Nov 13, 2026, Alion lists 10 companies most like Sizewell C: Westinghouse Electric Company, Commonwealth Fusion Systems, Rolls-Royce SMR, United Kingdom Atomic Energy Authority, TerraPower, General Matter, The Nuclear Company, Canadian Nuclear Laboratories, Assystem and Helion Energy.
- Sizewell C itself has 107 open roles on Alion.
- Of them, Westinghouse Electric Company is hiring the most, with 869 open roles.
- Commonwealth Fusion Systems has raised the most venture funding on record: $2.7B.
- Open roles at Commonwealth Fusion Systems rose the most: from 111 on Oct 12, 2026 to 130 now.
Sizewell C and its competitors compared
Open roles are the postings Alion lists today; their change is shown only for career sites that state posting dates. Funding is the venture money on record. A dash means Alion holds no figure.
| Company | Open roles | Change | Raised | Last round | Employees | Headquarters | Main technologies | Hiring in |
|---|---|---|---|---|---|---|---|---|
Sizewell C
This company
|
107 | – | – | Venture round2025 | 1001-5000 | London, United Kingdom | HPC, Microsoft Excel, Power BI | United Kingdom |
Westinghouse Electric Company
In common: Nuclear Energy, Nuclear Engineering · Python, SQL, Databricks |
869 | – | – | – | 5000+ | Cranberry Township, United States | Power BI, Python, Microsoft Excel | United States, Poland, Spain +11 more |
Commonwealth Fusion Systems
In common: Nuclear Energy, Nuclear Engineering · Python, SQL, Power BI |
130 | +17%since Oct 12, 2026 | $2.7B | Series B $863M2025 | 1001-5000 | Devens, United States | Python, AutoCAD, SolidWorks | United States |
Rolls-Royce SMR
In common: Nuclear Energy, Nuclear Engineering · Python, SQL, Power BI · headquarters in United Kingdom |
50 | – | – | Venture round2025 | 501-1000 | Derby, United Kingdom | Verification & Validation, MBSE, Power BI | United Kingdom |
United Kingdom Atomic Energy Authority
In common: Nuclear Energy, Nuclear Engineering · Python, SQL, Power BI · headquarters in United Kingdom |
26 | – | – | – | 1001-5000 | Culham, United Kingdom | C++, Python, Fortran | United Kingdom |
TerraPower
In common: Nuclear Energy, Nuclear Engineering · Python, SQL, Power BI |
70 | – | – | – | 501-1000 | Bellevue, United States | ASME NQA-1, Python, Microsoft Excel | United States |
General Matter
In common: Nuclear Energy, Nuclear Engineering · Python, SQL, Databricks |
125 | +14%since Oct 12, 2026 | – | – | 51-200 | San Francisco, United States | Python, AutoCAD, C++ | United States |
The Nuclear Company
In common: Nuclear Energy, Nuclear Engineering · Python, SQL, Databricks |
49 | +2%since Oct 12, 2026 | $51M | Venture round $51M2025 | 51-200 | Columbia, United States | Python, AWS, Machine Learning | United States |
Canadian Nuclear Laboratories
In common: Nuclear Energy, Nuclear Engineering · Python, SQL, Power BI |
90 | – | – | – | 1001-5000 | Chalk River, Canada | AutoCAD, Windows, EVMS | Canada |
Assystem
In common: Nuclear Energy, Nuclear Engineering · Python, SQL, Databricks |
616 | – | – | – | 5000+ | Courbevoie, France | AutoCAD, Python, Power BI | United Kingdom, France, India +6 more |
Helion Energy
In common: Nuclear Energy, Nuclear Engineering · Python, SQL, Power BI |
77 | – | $500M | Venture round $500M2021 | 501-1000 | Everett, United States | Python, MATLAB, SolidWorks | United States, Switzerland |
How the list is made
The list comes from Alion's similar-companies engine, the same one AI agents query through the Alion MCP server. A company ranks higher when it shares more of Sizewell C's industry segments and is less spread over others, when its job postings name the same technologies, when it is headquartered in the same country and when its size is close. The list is rebuilt every week.
How to cite this page
These figures are published under a free licence. You may reuse them, including commercially, as long as you credit Alion and link back to this page.
Alion, "Sizewell C competitors and alternatives: 10 similar companies compared on hiring and funding", as of Nov 13, 2026. https://alion.io/company/sizewellc/competitors