---
title: 'Nuclear Engineer at Radiant Industries'
canonical: 'https://feeny.ai/job/nuclear-engineer-radiant-industries-el-segundo-5k2acrrkc5ca'
type: 'job'
last_seen: '2026-09-07'
---

# Nuclear Engineer at Radiant Industries

- **Company:** [Radiant Industries](https://feeny.ai/companies/radiant-industries)
- **Location:** El Segundo, CA
- **Compensation:** $107k–$146k
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-08-07
- **Last confirmed live:** 2026-09-07
- **Apply:** https://jobs.ashbyhq.com/radiant-industries/0fea3334-e41f-45ee-b5e8-f54ce00f6539

## Job description

## ABOUT RADIANT

Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.

## ABOUT THE ROLE

Radiant is seeking a highly motivated Nuclear Engineer responsible for developing nuclear engineering solutions for our Kaleidos microreactor. This may include nuclear engineering areas such as radiation shielding, criticality safety, accident dose consequence, reactor physics modeling and design, transient analysis, and radiation detection. You will lead and own nuclear engineering initiatives and studies, strategic direction, and work closely with a collaborative nuclear and engineering team in a fast-paced startup environment. The ideal candidate is passionate about advanced reactor design, detail-oriented, effectively communicates, and a tenacity to solve interesting technical challenges.

Responsibilities & Duties :

- Ownership of Nuclear design and analysis, examples include:
- Shielding: Operational dose and shutdown activation analysis, waste categorization, and alignment of shielding design to customer and regulatory requirements.
- Neutronics: Analysis of ex-vessel reactor fluxes and energy deposition, criticality safety, and verification and validation (V&V) of the nuclear toolbox and reactor models.
- Accident and Dose Consequence: Radiological dose consequence from different accident scenarios for the Kaleidos demonstration and production units.
- Transient Analysis: Run coupled neutronics and thermal calculations to further understanding of the reactor dynamics of the Kaleidos reactor design.
- Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.
- Other nuclear design and analysis duties as assigned.

Required Qualifications & Skills:

- Bachelor’s degree in nuclear engineering or equivalent degree from an accredited institution.
- 1-2+ years of nuclear engineering industry experience (MS equivalent to 2 yrs).
- Experience with radiation transport methods, including with codes such as MCNP/OpenMC/Serpent.
- Proficient in at least one of the following programming languages: Python, C++, C#, FORTRAN, or another scientific computing language.
- Basic knowledge of thermal hydraulic principles.
- Self-motivated with strong organizational, written, and oral communication skills.
- Experience working in an engineering organization and developing high-quality work.

Desired Qualifications & Skills

- Experience with variance reduction techniques and associated software (Attila4MC and/or ADVANTG), is a plus.
- Strong experience with OpenMC, Serpent, MCNP, Attila4MC, MOOSE, RELAP, Pronghorn, GRIFFIN, or other similar nuclear software packages.
- Competency in distributed software development processes and high-performance computing environments.
- Familiarity with CAD design software (NX, SolidWorks, and/or SpaceClaim), is a plus.
- Familiarity with dose consequence methods and software such as MAACS or NRC-RADTRAN.
- At least 1 year of software development or scripting experience.
- Hands-on experience designing hardware and/or performing tests.

Additional Requirements:

- Must be willing to work extended hours and weekends as necessary to accomplish our mission.
- Must work 100% onsite at El Segundo HQ.

## BENEFITS AND PERKS

- Stock: Substantial incentive stock plan for all full-time employees.
- Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
- One Medical: Sponsored memberships for employees and their dependents.
- Vision: 100% top tier plan coverage + 50% for dependents.
- Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
- Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
- 8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
- Daily catered lunch. Free snacks and drinks.
- Flexible PTO policy. Remote workday allocation.
- Company and team-bonding events, happy hours and in-person camaraderie.
- Beautiful El Segundo headquarters close to the Pacific Ocean.

Total Compensation and Benefits Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.

The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.

We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.

This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.

## About Radiant Industries

## Company Overview
- **One-liner**: Radiant Industries is building the world’s first mass‑produced, portable nuclear microreactor (Kaleidos) to replace diesel generators with zero‑emission, resilient power for remote sites, hospitals, data centers, and military installations.
- **Entity Type**: Private (Series D – $300M raised in December 2025, led by Lockheed Martin Ventures)
- **Headquarters**: El Segundo, California, USA
- **Founded**: 2020 (some sources list 2019)
- **Founders**: Not publicly disclosed

## Core Business
- **Primary industry**: Nuclear electric power generation / clean energy
- **Target customers**: B2B – remote communities, hospitals, data centers, military bases, industrial sites that currently rely on diesel generators or unstable grids
- **Mission**: To bring one of the world’s first factory‑constructed microreactors to market, providing portable, zero‑emissions power anywhere, anytime.

## Products & Services
- **[Kaleidos Microreactor](https://www.radiantnuclear.com/)**: A 1 MW electric / 1.9 MW thermal portable nuclear reactor packaged in a shipping container. It uses helium gas cooling and TRISO fuel (meltdown‑proof ceramic uranium particles). Delivered by truck or aircraft, installed without site excavation, and can reach full power the next day. After 5+ years the entire container is returned to the factory for refueling; up to four fuel cycles yield a 20‑year product lifetime. Customers purchase via Power Purchase Agreements (PPAs) or direct unit sales.

## Market Standing
- **Valuation / Market Cap**: Not disclosed
- **Key Metric**: Total funding raised – **$622.6M** (as of early 2026)
- **Notable Investors/Partners**: Andreessen Horowitz (led Series B), Lockheed Martin Ventures (led Series D), plus 18+ other investors across Series B, C, and D rounds
- **Growth Signals**:
  - Headcount grew **141% YoY** to 157 employees (as of mid‑2026)
  - 64 active job postings (+178% YoY)
  - Plans to test its development reactor in **2026** – which would be the first new commercial reactor design to achieve a fueled test in over 50 years
  - Initial customer deployments targeted for **2028**
  - SBIR Phase II awards from the U.S. Air Force for nuclear microreactor installation energy resilience

## Competitive Advantages
- **Portability & speed**: Delivered in a standard shipping container, installed in one day, no on‑site water or excavation needed.
- **Passive safety**: TRISO fuel is meltdown‑proof; the core is cooled by natural convection (air jacket) without pumps.
- **Factory‑built, factory‑refueled**: No nuclear waste or infrastructure left on site after the container is returned.
- **High energy density**: Over 110× the energy density of existing diesel systems.
- **Fleet monitoring**: Hundreds of units can be monitored 24/7 from a centralized control center.

## Strategic Focus
- Complete fueled testing of the Kaleidos prototype in 2026.
- Secure regulatory approvals (special nuclear material license, Part 7 license).
- Scale manufacturing for initial customer deployments beginning in 2028.
- Expand into military, commercial, and humanitarian markets (disaster relief, remote microgrids, backup power).

## Why Work Here
- **Culture & mission**: High‑impact climate tech – directly replacing diesel generators with clean nuclear power. Rated 5.0/5.0 on employer reviews (5 reviews) with strong scores for culture (4.7) and career growth (4.8).
- **Work location**: On‑site in El Segundo, CA (steps from the Pacific Ocean, near downtown). Employees work from a physical office.
- **Perks**: Company equity, relocation assistance, free daily meals, commuter benefits, onsite parking, generous parental leave, family medical leave, onsite Mother’s Room, dental/health insurance, FSA.
- **Diversity & inclusion**: Mandated unconscious bias training; hiring practices that promote diversity.
- **Tech stack**: React, TypeScript, Python, C++, C#, Kubernetes, Docker, PostgreSQL, AWS, Ansys, SolidWorks, Altium, and more. Engineers work on cutting‑edge nuclear, mechanical, and embedded systems.
- **Growth trajectory**: 141% headcount growth in the past year; 64 open roles across engineering, regulatory, supply chain, and operations.

## Sources
1. [radiantnuclear.com](https://www.radiantnuclear.com/) – Product details, specs, deployment model
2. [builtin.com](https://builtin.com/company/radiant) – Company overview, perks, culture, tech stack, reviews
3. [linkedin.com](https://www.linkedin.com/company/r-a-d-i-a-n-t) – Funding, headcount, employee growth, locations, key executives
4. [sbir.gov](https://www.sbir.gov/portfolio/1655711) – SBIR awards, Phase II contracts with U.S. Air Force
5. [jobs.ashbyhq.com](https://jobs.ashbyhq.com/radiant-industries) – Current open positions (64+)

## Other roles at Radiant Industries

- [Senior FPGA Engineer, Verification](https://feeny.ai/job/senior-fpga-engineer-verification-radiant-industries-el-segundo-kher3k7r7tf4) — El Segundo, CA
- [Senior Technical Program Manager, Security & IT](https://feeny.ai/job/senior-technical-program-manager-security-it-radiant-industries-el-segundo-mj8xghn64hqs) — El Segundo, CA
- [Senior Tooling Engineer](https://feeny.ai/job/senior-tooling-engineer-radiant-industries-el-segundo-z4bzp5ganp23) — El Segundo, CA
- [Permitting Manager](https://feeny.ai/job/permitting-manager-radiant-industries-washington-fm0smrn7ftzy) — Washington, DC
- [Export Controls Specialist](https://feeny.ai/job/export-controls-specialist-radiant-industries-el-segundo-3wzkcesyayym) — El Segundo, CA
- [Director of Policy and Government Affairs](https://feeny.ai/job/director-of-policy-and-government-affairs-radiant-industries-washington-9m6ww49dv8jy) — Washington, DC
- [Director, Nuclear Engineering](https://feeny.ai/job/director-nuclear-engineering-radiant-industries-el-segundo-s73ew6cvq8eg) — El Segundo, CA
- [Indirect Procurement Manager](https://feeny.ai/job/indirect-procurement-manager-radiant-industries-el-segundo-xvg0ber6d94z) — El Segundo, CA
- [Staff Structures Engineer](https://feeny.ai/job/staff-structures-engineer-radiant-industries-el-segundo-wqjgjtkddthf) — El Segundo, CA
- [Supplier Quality / Development Engineer](https://feeny.ai/job/supplier-quality-development-engineer-radiant-industries-el-segundo-8t93ghagzeak) — El Segundo, CA