ZipRecruiter

Log In

1

Reactor Engineer Jobs in California (NOW HIRING)

Radiant

Principal Nuclear Engineer

El Segundo, CA · On-site

$207K - $256K/yr

The company's first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be ... About the Role Radiant is seeking a Principal Nuclear Engineer to lead the interdisciplinary ...

Oklo

Neutronics Analysis Engineer

Santa Clara, CA · On-site +1

The engineer will also support verification and validation activities and contribute to licensing ... Be aware of and familiar with fast reactor core design and analysis work being performed ...

Antares

Senior, Civil Engineer

Los Angeles, CA · On-site

$140K - $185K/yr

About the Team The Antares Reactor Deployments team is responsible for bringing the Antares R1 microreactor from the factory to operational service. Working across engineering, manufacturing ...

Oklo

Neutronics Analysis Engineer

Santa Clara, CA · On-site

The engineer will also support verification and validation activities and contribute to licensing ... Be aware of and familiar with fast reactor core design and analysis work being performed ...

Radiant

Nuclear Engineer, Core Physics

El Segundo, CA · On-site

$106K - $146K/yr

The company's first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be ... About the Role Radiant is a seeking a Nuclear Engineer, Core Physics responsible for designing and ...

Radiant

Systems Engineer

El Segundo, CA · On-site

$133K - $190K/yr

The company's first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be ... This role bridges systems engineering, design, analysis, manufacturing, and operations. As a ...

Radiant Industries

Systems Engineer

El Segundo, CA · On-site

$133K - $190K/yr

The company's first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be ... This role bridges systems engineering, design, analysis, manufacturing, and operations. As a ...

Radiant

Certification Engineer

El Segundo, CA · On-site

$133K - $190K/yr

The company's first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be ... This role bridges systems engineering, design, analysis, manufacturing, and operations. As a ...

Radiant Industries

Certification Engineer

El Segundo, CA · On-site

$133K - $190K/yr

The company's first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be ... This role bridges systems engineering, design, analysis, manufacturing, and operations. As a ...

Radiant

Senior Nuclear Engineer

El Segundo, CA · On-site

$133K - $184K/yr

The company's first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be ... About the Role Radiant is seeking a driven Senior Nuclear Engineer to join our team! You will own ...

Radiant

Nuclear Engineer, Sensors

El Segundo, CA · On-site

$106K - $146K/yr

The company's first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be ... About the Role Radiant is seeking a highly motivated Nuclear Engineer to own sensor and ...

Radiant

Senior Test Engineer

El Segundo, CA · On-site

$133K - $184K/yr

The company's first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be ... About the Role We are seeking a Senior Test Engineer to design and implement mission-critical ...

Radiant Industries

Senior Nuclear Engineer

El Segundo, CA · On-site

$133K - $184K/yr

The company's first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be ... About the Role Radiant is seeking a driven Senior Nuclear Engineer to join our team! You will own ...

Ammobia

Chemical R&D Engineer

San Francisco, CA · On-site

$100K - $200K/yr

Conduct and manage tests on advanced reactor systems and materials characterization systems, including specifying/building custom reactor equipment * Transfer lab and bench scale R&D learnings and ...

Ammobia

Chemical R&D Engineer

San Francisco, CA

$100K - $200K/yr

Conduct and manage tests on advanced reactor systems and materials characterization systems, including specifying/building custom reactor equipment * Transfer lab and bench scale R&D learnings and ...

previous page

Showing results 41-60

All JobsReactor Engineer JobsReactor Engineer Jobs in California

Reactor Engineer information

See California salary details

$58.7K

$110.2K

$200.3K

How much do reactor engineer jobs pay per year?

As of Sep 3, 2026, the average yearly pay for reactor engineer in California is $110,170.00, according to ZipRecruiter salary data. Most workers in this role earn between $79,400.00 and $130,800.00 per year, depending on experience, location, and employer.

What is a reactor engineer?

Reactor Engineers are professionals who design, operate, and maintain nuclear reactors. They are responsible for ensuring the safe and efficient functioning of reactors used for power generation, research, or medical purposes. Their work involves monitoring reactor systems, conducting safety assessments, and developing procedures to prevent accidents. Reactor Engineers also analyze reactor performance data and collaborate with other engineers and scientists to optimize reactor operations.

What are the key skills and qualifications needed to thrive as a reactor engineer, and why are they important?

To thrive as a Reactor Engineer, you need a solid background in nuclear engineering, reactor physics, and safety protocols, typically supported by a degree in nuclear engineering or a related field. Familiarity with simulation software, reactor monitoring systems, and safety certification such as Fundamentals of Engineering (FE) or Professional Engineering (PE) is often required. Strong analytical thinking, attention to detail, and effective communication skills help you solve complex technical problems and work within multidisciplinary teams. These skills ensure the safe, efficient, and regulatory-compliant operation of nuclear reactors, which is critical for both safety and energy production.

What are some common challenges faced by reactor engineers during routine operations and how are they addressed?

Reactor Engineers often encounter challenges such as maintaining reactor stability, troubleshooting instrumentation issues, and ensuring compliance with strict safety protocols. These challenges are typically managed through continuous monitoring, collaboration with multidisciplinary teams (including safety, operations, and maintenance personnel), and adherence to established procedures. Proactive communication and regular training enable Reactor Engineers to respond effectively to unexpected events and maintain optimal reactor performance.

What is the difference between Reactor Engineer vs Nuclear Engineer?

AspectReactor EngineerNuclear Engineer
CredentialsBachelor's in Nuclear Engineering or related field; often requires licensing or certificationBachelor's or higher in Nuclear Engineering; may also require licensing
Work EnvironmentDesign, operate, and maintain nuclear reactors, often in power plants or research facilitiesResearch, develop, and improve nuclear systems, including reactors and radiation safety
Industry UsagePrimarily in power generation, naval propulsion, and research reactorsResearch institutions, government agencies, and industry R&D

Reactor Engineers focus on the operation and safety of nuclear reactors, ensuring they run efficiently and safely. Nuclear Engineers have a broader scope, including research, development, and design of nuclear systems. Both roles require similar educational backgrounds and certifications, but Reactor Engineers are more hands-on with reactor operation, while Nuclear Engineers often work on innovation and system improvements.

What are popular job titles related to Reactor Engineer jobs in California?

For Reactor Engineer jobs in California, the most frequently searched job titles are:

What job categories do people searching Reactor Engineer jobs in California look for?

The top searched job categories for Reactor Engineer jobs in California are:

What cities in California are hiring for Reactor Engineer jobs?

Cities in California with the most Reactor Engineer job openings:

Reactor Engineer jobs near you
Infographic showing various Reactor Engineer job openings in California as of August 2026, with employment types broken down into 91% Full Time, 6% Part Time, and 3% Contract. Highlights an 86% Physical, 5% Hybrid, and 9% Remote job distribution, with an average salary of $110,170 per year, or $53 per hour.

Principal Nuclear Engineer

Radiant

El Segundo, CA • On-site

$207K - $256K/yr

Full-time

Medical, Dental, Vision, Life, PTO

This job post has expired today. Applications are no longer accepted.

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 Principal Nuclear Engineer to lead the interdisciplinary nuclear engineering work supporting Kaleidos. This role combines people leadership with hands-on technical ownership across core physics, neutron and radiation transport, shielding, activation and dose, thermal-hydraulics, safety analysis, instrumentation and controls, operations, and regulatory evaluations.
You will guide work from requirements and early design trades through analysis, verification and validation, testing, and regulatory documentation. The ideal candidate brings deep expertise in neutron transport and Monte Carlo methods, along with the judgment to translate complex analysis into practical reactor design and operational decisions.
Responsibilities & Duties
  • Lead an interdisciplinary team working across reactor physics, core performance, shielding, dose and activation, thermal-hydraulics, safety analysis, I&C, and operations.
  • Establish technical priorities, project plans, resource needs, and clear ownership across the nuclear engineering organization.
  • Serve as a technical authority for neutron and radiation transport and Monte Carlo simulation methods.
  • Own nuclear engineering projects from requirements capture and design iteration through model development, analysis, technical review, and final documentation.
  • Guide analyses of criticality, reactivity control, shutdown margin, power distribution, depletion, temperature feedback, radiation transport, dose, activation, and shielding performance.
  • Translate analytical results into actionable requirements and design decisions affecting the core, shielding, control systems, instrumentation, fluid systems, and structures.
  • Establish technically rigorous practices for model verification and validation, peer review, configuration control, uncertainty evaluation, and documentation.
  • Collaborate with reactor systems, thermal, mechanical, electrical, test, operations, safety, and regulatory teams to resolve multidisciplinary design challenges.
  • Translate nuclear standards and regulatory requirements into analysis plans, design criteria, calculation packages, and verification activities.
  • Support reactor testing and startup by defining analysis needs, instrumentation requirements, acceptance criteria, and methods for comparing predicted and measured performance.
  • Identify technical risks, drive complex problems through closure, and communicate decisions and recommendations to engineering teams and company leadership.
  • Mentor engineers through technical guidance, actionable feedback, and regular coaching.
Required Qualifications & Skills
  • Bachelor's degree in nuclear engineering or a related technical discipline from an accredited institution.
  • 9+ years of relevant nuclear engineering experience across reactor design, analysis, testing, licensing, safety, or operations.
  • Demonstrated experience leading complex nuclear engineering projects and multidisciplinary technical teams.
  • Experience hiring, managing, mentoring, or technically leading nuclear engineers.
  • Deep knowledge of neutron transport theory, Monte Carlo simulation methods, nuclear data, and statistical convergence.
  • Professional experience developing and applying MCNP, OpenMC, or comparable neutron and radiation transport models.
  • Strong understanding of criticality, reactivity coefficients, depletion, power distribution, shutdown margin, radiation transport, and uncertainty analysis.
  • Experience translating analysis into reactor design decisions, technical requirements, safety conclusions, or regulatory documentation.
  • Familiarity with model verification and validation, configuration control, peer review, and nuclear software quality practices.
  • Strong written and verbal communication skills, including the ability to explain complex analyses, assumptions, uncertainties, and technical conclusions.
Preferred Qualifications & Skills
  • Master's degree or Ph.D. in nuclear engineering or a related discipline.
  • Experience with high-temperature gas-cooled reactors, microreactors, advanced reactors, or first-of-a-kind nuclear systems.
  • Experience with SCALE, Serpent, Shift, Griffin, MOOSE-based applications, or similar analysis tools.
  • Proficiency with Python or another language used for simulation automation and data post-processing.
  • Experience with coupled neutronics and thermal-hydraulics or other multiphysics analyses.
  • Familiarity with DOE authorization, NRC licensing, nuclear codes and standards, or regulatory safety analysis.
  • Experience supporting reactor testing, commissioning, startup, or operational readiness.
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.

Apply