Company lists · Data refreshed September 2026

Top 25 Nuclear engineering firms worldwide

Name: Nuclear engineering firms worldwide
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 17, 2026 416 companies tracked

RevenueBase identified 416 nuclear engineering firms worldwide as of September 2026 and tracks 104,483 professional contacts across them, including 36,863 with verified work emails and 0 with mobile numbers. The United States is the largest market and Bristol the largest hub.

This list covers nuclear engineering firms worldwide, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 17, 2026. Country and city lists for nuclear engineering firms follow the table.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 17, 2026 86% judged on-target in blind review

416Companies

104,483Contacts tracked

36,863Verified emails

0Mobile numbers

Explore this list → Free signup · no credit card · 500 free credits

The 25 largest nuclear engineering firms worldwide

Ranked by team size

Top 25 of 416 nuclear engineering firms worldwide, ranked by team size, largest first. Data refreshed Sep 17, 2026. RevenueBase Smart Search rates how each company's information relates to nuclear engineering firms: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Atkinsréalis	Strong evidence	Montreal, QC, CanadaHQ checked Sep 17, 2026	10001+	22,733 contacts →
	Strong evidence “We are a world-class engineering services and nuclear organization.” Source: RevenueBase Database · checked Sep 17, 2026
2	Framatome	Partial evidence	Courbevoie, FranceHQ checked Sep 17, 2026	10001+	12,439 contacts →
	Partial evidence “Framatome is an international leader in nuclear energy recognized for its innovative, digital and value added solutions for the global nuclear fleet.” Source: RevenueBase Database · checked Sep 17, 2026
3	Westinghouse Electric Company	Partial evidence	Cranberry Township, PA, United StatesHQ checked Sep 17, 2026	5,001-10,000	10,898 contacts →
	Partial evidence “Westinghouse Electric Company is the world's leading supplier of safe and innovative nuclear technology.” Source: RevenueBase Database · checked Sep 17, 2026
4	Atkins	Indirect evidence	Epsom, United KingdomHQ checked Sep 17, 2026	10001+	9,297 contacts →
	Indirect evidence “Atkins is now AtkinsRéalis.” Source: RevenueBase Database · checked Sep 17, 2026
5	Assystem	Strong evidence	Courbevoie, FranceHQ checked Sep 17, 2026	5,001-10,000	6,518 contacts →
	Strong evidence “Assystem, one of the world's leading independent nuclear engineering companies, is committed to accelerating the energy transition.” Source: RevenueBase Database · checked Sep 17, 2026
6	BWXT	Indirect evidence	Lynchburg, VA, United StatesHQ checked Sep 17, 2026	5,001-10,000	3,832 contacts →
	Indirect evidence “At BWX Technologies, Inc.(NYSE: BWXT), we are People Strong, Innovation Driven.” Source: RevenueBase Database · checked Sep 17, 2026
7	Canadian Nuclear Laboratories	Partial evidence	Chalk River, ON, CanadaHQ checked Sep 17, 2026	1,001-5,000	2,229 contacts →
	Partial evidence “Canada's premier nuclear science and technology organization.” Source: RevenueBase Database · checked Sep 17, 2026
8	Edvance	Partial evidence	Montrouge, FranceHQ checked Sep 17, 2026	1,001-5,000	1,780 contacts →
	Partial evidence “Edvance, a joint subsidiary of EDF and Framatome, is responsible for the design and implementation (studies, procurement assistance, assembly and commissioning) of nuclear islands…” Source: RevenueBase Database · checked Sep 17, 2026
9	Orano DS	Indirect evidence	Massy, FranceHQ checked Sep 17, 2026	5,001-10,000	1,684 contacts →
	Indirect evidence “Orano DS fait partie du Groupe Orano, le fournisseur de référence du cycle du combustible nucléaire.” Source: RevenueBase Database · checked Sep 17, 2026
10	Onet Technologies	Strong evidence	Marseille, FranceHQ checked Sep 17, 2026	1,001-5,000	1,664 contacts →
	Strong evidence “Onet Technologies has 40 years of experience in the nuclear industry, with a strong expertise in engineering and services for reactor maintenance; dismantling, decommissioning and…” Source: RevenueBase Database · checked Sep 17, 2026
11	Cavendish Nuclear	Partial evidence	Birchwood, United KingdomHQ checked Sep 17, 2026	5,001-10,000	1,592 contacts →
	Partial evidence “Cavendish Nuclear is a core part of Babcock International Group’s Nuclear Sector.” Source: RevenueBase Database · checked Sep 17, 2026
12	NUVIA	Indirect evidence	Rueil Malmaison, FranceHQ checked Sep 17, 2026	1,001-5,000	1,537 contacts →
	Indirect evidence “Subsidiary of the world-leading VINCI group, NUVIA is an international company that has been operating on highly regulated and sensitive industrial sites for over 60 years.” Source: RevenueBase Database · checked Sep 17, 2026
13	Technicatome	Indirect evidence	Villiers-le-bâcle, FranceHQ checked Sep 17, 2026	1,001-5,000	1,315 contacts →
	Indirect evidence “TechnicAtome est spécialisée, depuis plus de 50 ans, dans la conception, la réalisation, la mise en service et le maintien en conditions opérationnelles des réacteurs nucléaires…” Source: RevenueBase Database · checked Sep 17, 2026
14	Energysolutions	Partial evidence	Salt Lake City, UT, United StatesHQ checked Sep 17, 2026	1,001-5,000	1,254 contacts →
	Partial evidence “EnergySolutions is an international nuclear services company headquartered in Salt Lake City, Utah, and Charlotte, North Carolina, with operations across the United States and…” Source: RevenueBase Database · checked Sep 17, 2026
15	Spie Nucléaire	Indirect evidence	Cergy-pontoise Cedex, FranceHQ checked Sep 17, 2026	1,001-5,000	1,079 contacts →
	Indirect evidence “À propos de SPIE Nucléaire Filiale de SPIE France, SPIE Nucléaire est le partenaire de référence multi-technique dans la conception, la réalisation, les travaux de modification…” Source: RevenueBase Database · checked Sep 17, 2026
16	X-Energy	Partial evidence	Rockville, MD, United StatesHQ checked Sep 17, 2026	501-1,000	1,055 contacts →
	Partial evidence “X-energy is delivering the next generation of carbon-free energy by reinventing nuclear power.” Source: RevenueBase Database · checked Sep 17, 2026
17	Terrapower	Partial evidence	Bellevue, WA, United StatesHQ checked Sep 17, 2026	501-1,000	913 contacts →
	Partial evidence “TerraPower is a leading nuclear innovation company that strives to improve the world through nuclear energy and science.” Source: RevenueBase Database · checked Sep 17, 2026
18	Centrus Energy Corp	Partial evidence	Bethesda, MD, United StatesHQ checked Sep 17, 2026	201-500	684 contacts →
	Partial evidence “Centrus Energy is a trusted American supplier of nuclear fuel and services for the nuclear power industry, helping meet the growing need for clean, affordable, carbon-free energy.” Source: RevenueBase Database · checked Sep 17, 2026
19	Newcleo	Partial evidence	Paris, ItalyHQ checked Sep 17, 2026	501-1,000	640 contacts →
	Partial evidence “Since launching in 2021 newcleo has quickly established itself as innovator in the field of nuclear energy.” Source: RevenueBase Database · checked Sep 17, 2026
20	Kepco E&c	Indirect evidence	Port Elgin, CanadaHQ checked Sep 17, 2026	1,001-5,000	579 contacts →
	Indirect evidence “KEPCO E&C was founded in 1975 with the objective of obtaining core technology.” Source: RevenueBase Database · checked Sep 17, 2026
21	AREVA	Indirect evidence	Paris La Defense, FranceHQ checked Sep 17, 2026	10001+	558 contacts →
	Indirect evidence “We are now Orano!” Source: RevenueBase Database · checked Sep 17, 2026
22	Urenco Global	Indirect evidence	London, United KingdomHQ checked Sep 17, 2026	1,001-5,000	539 contacts →
	Indirect evidence “Urenco is an international supplier of enrichment services and fuel cycle products with sustainability at the core of its business.” Source: RevenueBase Database · checked Sep 17, 2026
23	Dalkia EN	Indirect evidence	Courbevoie, FranceHQ checked Sep 17, 2026	501-1,000	485 contacts →
	Indirect evidence “Sur les centrales nucléaires du groupe EDF, nous intervenons sur tous les types de bâtiments, à la fois de production et tertiaires.” Source: RevenueBase Database · checked Sep 17, 2026
24	Kairos Power	Indirect evidence	Alameda, CA, United StatesHQ checked Sep 17, 2026	501-1,000	485 contacts →
	Indirect evidence “Kairos Power has a mission to enable the world’s clean energy transition to improve people’s quality of life while protecting the environment.” Source: RevenueBase Database · checked Sep 17, 2026
25	GSE Solutions	Strong evidence	Columbia, MD, United StatesHQ checked Sep 17, 2026	201-500	404 contacts →
	Strong evidence “GSE Solutions supports nuclear power and clean-energy fleets worldwide through integrated engineering services and software that strengthen operational performance.” Source: RevenueBase Database · checked Sep 17, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: nuclear engineering firms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names nuclear engineering firms.
Partial evidence: Its own public description names part of nuclear engineering firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name nuclear engineering firms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 416 nuclear engineering firms worldwide

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 36,863 reachable decision-makers.

Free signup · no credit card

View the full list →

Nuclear engineering firms worldwide at a glance

As of Sep 17, 2026

35.3%Verified-email coverage

251.2Average contacts per company

11-50Median size (employees)

2.2%Largest-city concentration · Bristol

Sep 17, 2026Page data refreshed

Companies by employee count

1-10

148

11-50

111

51-200

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among nuclear engineering firms, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
Coverage: 5 countries, largest first: the United States, France, the United Kingdom, Canada, Germany. Country and city lists for nuclear engineering firms are linked below.
What qualifies: Companies worldwide whose own description of what they do matches “nuclear engineering firms”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names nuclear engineering firms), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among nuclear engineering firms, and records with no verified work email.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 36,863 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 17, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Nuclear engineering firms by location

5 lists · largest first

Every Nuclear engineering firms list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names nuclear engineering firms, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many nuclear engineering firms are there worldwide?

RevenueBase identified 416 nuclear engineering firms worldwide as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Atkinsréalis, headquartered in Montreal, tops this list with the largest team on record.

Which country has the most nuclear engineering firms?

The United States leads with 228 companies, followed by France (74) and the United Kingdom (57). Every nuclear engineering firms list by country and city is linked on this page.

Which city has the most nuclear engineering firms?

Bristol leads with 9 headquartered companies, followed by London (8) and Lyon (8).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 36,863 verified decision-maker contacts tracked across these 416 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 17, 2026.

Ready to reach these companies? Verified emails and direct dials for all 416 nuclear engineering firms worldwide. Start with a free account, no credit card.

Download this list →

Related lists

Browse the directory

Browse: Companies home · Lists by location · New lists

About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.