Who Is Hiring in Advanced Fission? 933 Open Jobs at 23 Reactor Developers (October 2026)
For advanced reactor founders, hiring managers, licensing and QA leads, investors, and engineers considering a move into advanced nuclear.
Executive Summary
Press releases tell you who raised money. Job postings tell you who is spending it on people. Leveraging Gibboney Nuclear's October 2026 proprietary dataset of 125 developers of 178 designs, on October 21, 2026, we counted open job postings at 31 advanced reactor and small modular reactor (SMR) developers: our front runners, every reactor developer selected for the U.S. Department of Energy (DOE) Reactor Pilot Program and the DOE Nuclear Energy Launch Pad, and every company with an advanced reactor or light water SMR docket at the U.S. Nuclear Regulatory Commission (NRC).
We found 933 open postings at 23 developers. Four companies, Radiant, X-energy, TerraPower, and Valar Atomics, account for 45 percent of them. Across the 850 postings we could classify by job title, mechanical and electrical engineering roles outnumber nuclear engineering and analysis roles nearly three to one. Licensing and quality assurance (QA) together make up about one in ten openings, and operations and maintenance just 3 percent.
The pattern is consistent with an industry moving from design toward hardware. The developers hiring hardest are generally the ones closest to physical work, and the skills in highest demand are the ones needed to design, procure, build, and qualify equipment.
How many advanced reactor jobs are open right now?
Of the 31 developers we checked, 23 had openings posted publicly, for a total of 933. Eight had none posted: Deployable Energy, Scaled Atomics, Flibe Energy, Deep Atomic, Terra Innovatum, NuCube Energy, Atlas Atomics, and Reploy Power. That does not mean those companies are not hiring. Small teams often recruit through a contact form, their VC investor firm, an email address, or their own networks. A few are using LinkedIn job posts.
Which advanced reactor companies are hiring the most?
Radiant leads with 110 open postings, followed by X-energy (107), TerraPower (100), Valar Atomics (100), Antares Nuclear (88), Oklo (including Atomic Alchemy) (71), and Rolls-Royce SMR (67). Kairos Power (46) and NuScale Power (37) round out the top nine.
The long tail matters too. Thirteen developers have fewer than 30 openings each, including NANO Nuclear Energy (28), Last Energy (24), Terrestrial Energy (24), Aalo Atomics (19), Forge Atomics (17), and Hadron Energy (10).
Hiring follows hardware
Two of the top five, Antares Nuclear and Valar Atomics, reached zero-power criticality this summer under the DOE Reactor Pilot Program: Antares at Idaho National Laboratory in early June, and Valar on June 18 at the Utah San Rafael Energy Lab in Emery County, Utah. TerraPower is posting commissioning roles for its Kemmerer, Wyoming site.
There are exceptions. Deployable Energy reached criticality of its first Unity demonstration reactor at Idaho National Laboratory on June 30, yet lists no openings publicly and directs candidates to a contact form. Posting volume reflects how a company recruits as much as how fast it is growing.
Hiring by reactor technology
Sorted by reactor technology, gas-cooled designs lead with 354 postings (38 percent), followed by light water designs (210, 23 percent), sodium-cooled designs (194, 21 percent), heat pipe microreactors (99, 11 percent), and molten salt designs (76, 8 percent).
Gas-cooled
Radiant (110), X-energy (107), Valar Atomics (100), NANO Nuclear Energy (28), General Atomics EM2 (6), and BWXT’s BANR and Project Pele programs (3).
Light water
The larger SMR programs account for 157 postings: Rolls-Royce SMR (67), NuScale Power (37), Westinghouse AP300 (23), Holtec SMR-300 (20), and GE Vernova Hitachi BWRX-300 (10). Smaller light water developers add 53 more: Last Energy and its PWR-20 (24), Forge Atomics (17), Hadron Energy (10), and Deep Fission (2).
Sodium-cooled
TerraPower (100), Oklo (71), Aalo Atomics (19), and ARC Clean Technology (4).
Heat pipe
Antares Nuclear (88) and Westinghouse eVinci (11).
Molten salt
Kairos Power (46), Terrestrial Energy (24), and Natura Resources (6).
For large, diversified vendors (BWXT, General Atomics, GE Vernova Hitachi, Holtec, and Westinghouse), we counted only roles tied to the specific SMR or advanced reactor program, not the whole company. Technology categories follow the primary coolant in the Gibboney Nuclear developer dataset.
What engineering disciplines are most in demand?
We sorted 850 postings by job title, covering the 16 developers whose full job boards we could read. Mechanical and structural engineering is the largest category at 125 postings (15 percent), followed by electrical and instrumentation and controls (I&C) at 82 (10 percent) and nuclear engineering and analysis at 70 (8 percent).
Licensing and regulatory roles account for 38 postings (4 percent), and quality and configuration management for 48 (6 percent). Operations and maintenance is the smallest category at 25, which fits an industry where most units have not yet been built.
The mix varies by company. At Valar Atomics, a quarter of open roles are electrical and I&C positions. Antares Nuclear has 13 general applications on its board, more than any other developer, which suggests it is building a candidate pipeline ahead of specific openings.
What we don’t know yet
Trends. This is a single snapshot. We cannot yet say whether hiring is accelerating or slowing at any company.
Time to fill. We do not yet know how long postings stay open, which is the better measure of where talent is scarce.
Hiring outside job boards. Referrals, recruiters, and contractors do not show up in public postings, and some companies rely on them heavily.
Headcount. Open postings are not hires. A posting may represent several openings, or none that are actively funded.
What developers should do now
Hire licensing and QA before the application, not after. At about one in ten openings, licensing and QA roles are a small share of total hiring, and experienced candidates are scarce. A QA program has to be in place before safety-related work is performed under 10 CFR 50 Appendix B, so these hires set the pace for everything else.
Expect competition for mechanical and electrical engineers. These are the most sought-after disciplines, and candidates with Appendix B and NQA-1 experience are in demand across the whole nuclear industry, not just at reactor developers.
Start the operations organization early. Operator licensing under 10 CFR Part 55 requires training programs and examinations that take time to build. With operations at 3 percent of current postings, the industry is not yet hiring for the plants it plans to run.
Hire against confirmed funding. Hiring that outruns committed capital is one of the clearest warning signs of organizational strain. Sequence hiring to funding milestones, not to announcements.
Post your openings publicly. Candidates, partners, and investors read job boards. A careers page with current postings is evidence that a program is real. Even better are actual people announcing new roles at your organization on LinkedIn.
The bottom line
Advanced fission hiring is concentrated, hardware-driven, and engineering-heavy. The companies closest to building are hiring the most, and they are hiring the people who design, procure, and qualify equipment. The disciplines that make a program licensable, licensing and QA, are a small share of the total. That gap is worth watching, because in nuclear commercialization, the organization has to be ready before the hardware is.
Frequently Asked Questions
Q: How many open jobs are there at advanced reactor companies?
A: As of October 21, 2026, Gibboney Nuclear counted 933 open job postings at 23 advanced reactor and SMR developers, out of 31 developers career pages checked. The balance of the 125 developers are being watched, as many are still in stealth mode.
Q: Which advanced reactor companies are hiring the most?
A: Radiant (110), X-energy (107), TerraPower (100), and Valar Atomics (100) have the most open postings, together accounting for about 45 percent of the total.
Q: What disciplines are most in demand in advanced nuclear?
A: Mechanical and structural engineering (15 percent of classified postings) and electrical and I&C engineering (10 percent) are the largest categories, followed by nuclear engineering and analysis (8 percent).
Q: Are nuclear engineers in demand at advanced reactor companies?
A: Yes, but they are not the largest group. Nuclear engineering and analysis roles, including core design, safety analysis, and thermal-hydraulics, account for 70 of 850 classified postings. Mechanical and electrical roles together outnumber them nearly three to one.
Q: How many licensing and quality assurance jobs are open?
A: Licensing and regulatory roles account for 38 postings and quality and configuration management for 48, about one in ten classified postings combined.
Q: Which companies were included?
A: Our front runners, reactor developers selected for the DOE Reactor Pilot Program and the DOE Nuclear Energy Launch Pad, and companies with an advanced reactor or light water SMR docket at the NRC, drawn from the Gibboney Nuclear developer dataset of 125 developers and 178 designs.
Q: How were job postings counted?
A: We counted postings as listed on each company’s careers page or job board, including general applications. For large vendors such as BWXT, General Atomics, Westinghouse, GE Vernova Hitachi, and Holtec, we counted only roles tied to the SMR or advanced reactor program. Disciplines were assigned by keyword matching on job titles.
Q: How often will this analysis be updated?
A: We plan to update it regularly and add trends over time and how long postings stay open as data accumulates.
Q: How can my company’s jobs be included?
A: Send a link to your careers page to sarah.gibboney@gibboneynuclear.com and we will add it. It’s free.
Sarah Gibboney, P.E., is Founder and CEO of Gibboney Nuclear, PLLC, a licensing and quality assurance consultancy that helps advanced reactor developers become licensable, financeable, buildable, and deployable. She has 17 years of experience on the applicant and developer side, including co-authoring construction permit applications for both Advanced Reactor Demonstration Program awardees. Her book, Due Diligence: How to Design, License, and Deploy Advanced Reactors, is forthcoming from Rocky Flats Books.
References
Company careers pages and job boards (Greenhouse, Ashby, Lever, Workday, Jobvite, BambooHR, Rippling, Gusto, and company sites), accessed October 21, 2026.
World Nuclear News, “US Launch Pad supports reactor and fuel projects,” August 2026. https://www.world-nuclear-news.org/articles/us-launch-pad-supports-reactor-and-fuel-projects
POWER Magazine, “From Pilot to Launch: DOE Names First Four Nuclear Energy Launch Pad Developers,” April 2026. https://www.powermag.com/from-pilot-to-launch-doe-names-first-four-nuclear-energy-launch-pad-developers/
ANS Nuclear Newswire, “Antares achieves zero-power criticality at INL,” June 2026. https://www.ans.org/news/article-8099/antares-achieves-zeropower-criticality-at-inl/
POWER Magazine, “Valar Atomics’ Ward 250 Becomes Second Reactor to Go Critical Under DOE Pilot Program,” June 2026. https://www.powermag.com/valar-atomics-ward-250-becomes-second-reactor-to-go-critical-under-doe-pilot-program/
Deployable Energy, company website, accessed October 21, 2026. https://www.deployable.energy/
U.S. Nuclear Regulatory Commission, Advanced Reactors: Pre-Application Activities. https://www.nrc.gov/reactors/new-reactors/advanced/who-were-working-with/pre-application-activities.html
10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants. https://www.law.cornell.edu/cfr/text/10/appendix-B_to_part_50
10 CFR Part 55, Operators’ Licenses. https://www.law.cornell.edu/cfr/text/10/part-55
Gibboney Nuclear, proprietary advanced reactor developer dataset, October 2026 edition.
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