Company lists · Data refreshed September 2026
Top 25 Nuclear facility maintenance services worldwide
RevenueBase identified 411 nuclear facility maintenance services worldwide as of September 2026 and tracks 21,242 professional contacts across them, including 4,976 with verified work emails. The United States is the largest market and Sao Paulo the largest hub.
This list covers nuclear facility maintenance services 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 20, 2026. Country and city lists for nuclear facility maintenance services 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.
The 25 largest nuclear facility maintenance services worldwide
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 1,956 contacts → | ||||
Indirect evidence “NAES is the power generation industry’s largest independent services provider, with more than 40 years of experience managing risk and turning it into profits.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 2 | 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 20, 2026Thanks. The Data Team will review it. | |||||
| 3 | 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 20, 2026Thanks. The Data Team will review it. | |||||
| 4 | 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 20, 2026Thanks. The Data Team will review it. | |||||
| 5 | 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 20, 2026Thanks. The Data Team will review it. | |||||
| 6 | 487 contacts → | ||||
Strong evidence “TECNATOM was set up in 1957 as a Spanish engineering company specialising in guaranteeing the operation and maintenance of nuclear power plants to the highest levels of safety.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 7 | 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 20, 2026Thanks. The Data Team will review it. | |||||
| 8 | 408 contacts → | ||||
Partial evidence “Allied Power is dedicated to delivering best-in-class maintenance, modifications, and project services.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 9 | 406 contacts → | ||||
Partial evidence “Installation & Maintenance | Études, Ingénierie & Prestations Intellectuelles.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 10 | 345 contacts → | ||||
Partial evidence “Se ocupa de la primera parte del ciclo de combustible nuclear (diseño, fabricación y abastecimiento de combustible) prestando servicios de ingeniería y combustible a las Centrales…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 11 | 297 contacts → | ||||
Partial evidence “We support our clients by delivering safe, practical and efficient solutions to complex nuclear challenges, with a strong focus on disposability.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 12 | 290 contacts → | ||||
Indirect evidence “Al-Qussie International has been serving the government and private sectors in the Kingdom of Saudi Arabian since 1981, and we are proud of our reputation as one of the top…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 13 | 245 contacts → | ||||
Partial evidence “Founded in 1977 Sonic Systems International (SSI) is a full-service quality-consulting firm serving the nuclear power generation utility industry.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 14 | 234 contacts → | ||||
Partial evidence “Paragon tackles the most difficult challenges of the nuclear industry-those faced by the current operating fleet as well as the next generation of advanced reactors.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 15 | 211 contacts → | ||||
Partial evidence “Partner for the nuclear industry Bilfinger has successfully supported and advised customers from the nuclear industry for decades.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 16 | 198 contacts → | ||||
Indirect evidence “ŠKODA JS a.s.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 17 | 182 contacts → | ||||
Indirect evidence “LEADING THE MRO INDUSTRY Chalmers & Kubeck, Inc.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 18 | 143 contacts → | ||||
Strong evidence “Engineering, construction, and field services, encompassing nuclear, thermal, hydroelectric, renewable energy and electrical distribution facilities” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 19 | 138 contacts → | ||||
Partial evidence “ENWESA es una empresa de servicios y fabricación especializada en servicios nucleares, revisión y mantenimiento de válvulas industriales, fabricación de depósitos a presión e…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 20 | 131 contacts → | ||||
Indirect evidence “Established in 1960, Electric Motor and Contracting remains one of the largest independently owned electric motor and pump repair shops in the U.S.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 21 | 129 contacts → | ||||
Strong evidence “Hi Tech Solutions provides services to the nuclear power generation industry in four main areas: outage services (plant outages and reactor maintenance), nuclear fuel cycle…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 22 | 127 contacts → | ||||
Partial evidence “On 04 January 2018, AREVA NP, became Framatome, a designer, supplier and installer of nuclear steam supply systems.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 23 | 123 contacts → | ||||
Partial evidence “With more than a half-century in the nuclear business, is an expert in nuclear material handling and lifting equipment.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 24 | 116 contacts → | ||||
Strong evidence “NAC International Inc.(NAC) is an industry-leading provider of engineering, consulting, and nuclear fuel management solutions for nuclear facility operators, fuel cycle companies…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 25 | 92 contacts → | ||||
Indirect evidence “Servicios integrales de operación y mantenimiento principalmente en industria hidrocarburifera.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
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 facility maintenance services. 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 facility maintenance services.
- Partial evidence
- Its own public description names part of nuclear facility maintenance services, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name nuclear facility maintenance services. 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 411 nuclear facility maintenance services worldwide
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Nuclear facility maintenance services worldwide at a glance
As of Sep 20, 2026Companies by employee count
Email recency is reported on each country list linked below.
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 facility maintenance services, 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
- Every country. Country and city lists for nuclear facility maintenance services are linked below.
- What qualifies
- Companies worldwide whose own description of what they do matches “nuclear facility maintenance services”. 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 facility maintenance services), 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 facility maintenance services, 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, 4,976 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 20, 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 facility maintenance services by location
2 lists · largest firstEvery Nuclear facility maintenance services 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 facility maintenance services, 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 facility maintenance services are there worldwide?
RevenueBase identified 411 nuclear facility maintenance services 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?
NAES, headquartered in Issaquah, tops this list with the largest team on record.
Which country has the most nuclear facility maintenance services?
The United States leads with 71 companies, followed by France (48). Every nuclear facility maintenance services list by country and city is linked on this page.
Which city has the most nuclear facility maintenance services?
Sao Paulo leads with 7 headquartered companies, followed by Pierrelatte (4) and Klaipeda (3).
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 4,976 verified decision-maker contacts tracked across these 411 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 20, 2026.
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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.