Three sites, one reactor
Radiant Nuclear is building a one-megawatt-electric microreactor called Kilidos (also spelled Kalidos in company video). A June 2026 video walkthrough of the Kilidos demonstration campaign shows the team working 24/7 at their El Segundo facility and at Idaho National Laboratory, where a five-phase test campaign is underway:
- Phase 1: install reactor shield, install the nuclear reactor, load fuel, close up, walkdown inspections, double-check everything
- Phase 2: zero power critical — reactor becomes controllable at very low power
- Phase 3: take reactor above 1 MW thermal for 1–2 months, validating high-temperature models and demonstrating viable power output
- Phase 5: target 150 hours of continuous thermal operation, validating sustained high-temperature performance across all components
After phase 5, the company plans to use test data to license the design for first customer deliveries in roughly 18 months. Units will be built in El Segundo but fueled from a new facility under construction in Oak Ridge, Tennessee, on a former Manhattan Project site (K-27 and K-29 buildings). The video narrator states: "Back in El Segundo, our team will already be working on the next iteration of the Kalidos unit" while the current unit is still in test.
The radiantengineer.com, radiantengineering.co, and radiantengs.com sites belong to unrelated firms (solar/EPC, civil engineering, and oil-and-gas services respectively) and their staff listings are not Radiant Nuclear. The only first-party personnel reference appears in the Idaho test video, which refers to "team Radiant" without naming individuals or titles.
The hiring signal is the job board: six open roles, all principal or staff level, all in El Segundo, all carrying the same posted base range of $200,500–$314,475, as Zero G Talent's board data shows. The roles are Principal Electrical Engineer (Integration & Test), Principal Embedded Software Engineer, Staff Mechanical Engineer (Fluid Systems), Principal Turbomachinery Engineer, Principal Software Engineer (HPC DevOps), and Principal Power Systems Engineer.
What it pays
Zero G Talent's board shows a company-wide salary band of $94k–$284k, according to Zero G Talent's board data, with a median of $190k across 88 salaried positions. The live postings cluster at the top of that band: every role currently advertised mirrors the initial slate in level, location, and posted range.
| Role | Location | Posted Base Range (USD/year) |
|---|---|---|
| Principal Electrical Engineer, Integration & Test | El Segundo, CA | $200,500 – $314,475 |
| Principal Embedded Software Engineer | El Segundo, CA | $200,500 – $314,475 |
| Staff Mechanical Engineer, Fluid Systems | El Segundo, CA | $200,500 – $314,475 |
| Principal Turbomachinery Engineer | El Segundo, CA | $200,500 – $314,475 |
| Principal Software Engineer, HPC DevOps | El Segundo, CA | $200,500 – $314,475 |
| Principal Power Systems Engineer | El Segundo, CA | $200,500 – $314,475 |
Radiant's careers page states the company "compensates people for impact and invests in those who continue to raise the bar," describing new-hire packages as "base salary, substantial equity grants, and comprehensive health benefits." Equity grant sizes are not published. The $94k floor of the company-wide band likely captures junior technicians, operators, and administrative roles not visible in the current principal-heavy feed. Candidates for the posted seats should anchor expectations to the $200k–$315k window and treat the $190k median as a cross-company blend, not a midpoint for these openings.
How the hiring process works
Radiant Industries runs recruiting through Ashby (jobs.ashbyhq.com). Glassdoor hosts two separate entry clusters ("Radiant Digital" (16 reviews) and "Radiant (CA)" (12 reviews)) and Dataford.io aggregates 15 interview reports for Radiant Digital rating difficulty at 5.4/10. Neither source confirms these are the nuclear microreactor company. "Radiant Digital" is a known software consultancy. "Radiant (CA)" may refer to the laundry-services firm named in an EEOC action against Radiant Services Corp. and BaronHR, a $1.1 million settlement over coded hiring preferences at a commercial laundry facility.
Verifiable for Radiant Industries: the Ashby postings, LinkedIn listings for a Summer 2026 Software Engineering Intern and a 2026 New Graduate Technical Recruiter role, and the company's stated compensation philosophy. The recruiter role signals scaling intent.
The reactor, Kilidos, is a one-megawatt-electric portable microreactor targeting a five-year core life. Engineering spans thermal-hydraulic, neutronic, structural, and control-system domains. Candidates should expect a sequence typical of capital-intensive hardware startups: recruiter screen, hiring-manager technical conversation, onsite (or virtual equivalent) with multiple engineers, and a team-fit conversation. The hiring-manager call tests whether you've shipped relevant hardware — fluid systems, turbomachinery, high-power electrical, embedded firmware on bare metal, HPC build clusters.
The recruiter posting emphasizes "rapid-deploy capability" and "replace similar-sized diesel generators"; candidates who frame their background around field-deployed power systems, mobile generation, or austere-environment engineering speak the same language. The process can stretch to a couple of months given export-controlled nuclear work, background checks, and facility access clearances. Candidates who follow up with technical addenda rather than status requests, and who reference specific Radiant technical choices visible in public materials, signal the ownership mindset the company selects for.
Where the work happens
Every role on Radiant's board lists El Segundo, California as the duty station — 88 salaried roles at one address. The board shows no relocation packages advertised and no remote-only engineering roles. The video shows hardware (pressure vessel, test stands) in the El Segundo building, and the narrator confirms the next unit is being designed there while the current unit tests in Idaho.
The research does not document Radiant's internal facilities — no square-footage figures, test-stand inventories, or lab layouts. El Segundo's industrial base includes SpaceX's original factory, Relativity's Terran 1 production line, and a network of precision machining and welding shops, which can compress iteration cycles for a microreactor program. Parking, cafeteria, and security-cleared amenities are standard for defense-adjacent hardware companies in the area; the research does not specify which Radiant provides.
Candidates should ask in the technical screen about test-stand maturation: Has the team completed first critical heat removal testing? Is the turbomachinery loop running at prototypic speed and temperature? Are fuel-handling mockups operational? Those answers live in the facility, not the job description.
Who thrives here
The video and job postings emphasize rapid iteration and physical prototyping over formal process, and demonstrable execution ability over academic pedigree. The Ashby language (mirroring the careers page pledge to back people who keep raising the bar) maps to a promotion path tied to demonstrated capability expansion.
Glassdoor and Indeed reviews for "Radiant" are sparse and likely conflate multiple unrelated companies: radiant heating, solar design, commercial laundry. AmbitionBox's 3.5/5 from ~70 reviewers suffers the same ambiguity. The EEOC settlement against Radiant Services Corp. (laundry) is a different entity. The only first-party cultural data cleanly attached to the microreactor company is the jobs.ashbyhq.com statement and the role slate on the board.
The success profile that emerges: mid-to-senior engineers who have shipped hardware in nuclear, aerospace, or defense programs, who communicate through test data and redlines, and who treat process as a tool they pick up when it helps and set down when it doesn't. Radiant pays for that profile (the board band tops out near $284k) and the next Kilidos unit is already being designed in El Segundo while the current one runs in Idaho.
Working in frontier tech? Zero G Talent tracks the openings: see every open Radiant role, browse frontier tech jobs, the companies hiring, and the people building the field.