Reactor Operations Engineer

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
As a Reactor Operations Engineer, you will support the broader engineering team by providing operational insights and ensuring that once built, Radiant is prepared to test, commission, and support long term operations of Kaleidos reactors. This role offers a rare opportunity to bridge engineering, operations, licensing, and human factors in a highly technical and fast-paced environment. You will collaborate with a multidisciplinary team to translate complex hardware and software designs into clear, executable, and DOE or NRC compliant operations.
This position goes beyond traditional systems engineering - you will also gain hands-on experience as a Reactor Operator (RO), directly participating in the testing and commissioning of future reactor designs.
Responsibilities & Duties:

• Qualify as an operator to gain firsthand experience and ensure the team's work aligns with real-world execution.

• Implement the conduct of operations and fleet monitoring processes for Kaleidos reactors.

• Develop and refine operational procedures that integrate both software and hardware-in-the-loop testing.

• Support development of control algorithms for semi-automated and/or manual operations.

• Support the evaluation of integrated plant response to various events, accidents, and malfunctions.

• Participate in design reviews and provide feedback from an operations and maintenance perspective.

• Ensure all team deliverables meet DOE and NRC standards, maintaining strict formatting, clarity, and usability in procedural documentation.

• Collaborate closely with engineers to improve operator interfaces, procedural workflows, and software tools.

Required Qualifications & Skills:

• 4+ years of full-time professional experience in engineering problem-solving, including system design, analysis, or testing.

• Familiarity with the interrelationships and dependencies of complex systems, encompassing nuclear, mechanical, I&C and electrical systems - and their response as an integrated power plant system.

• Proficiency in managing or optimizing complex hardware and software processes for testing and operations.

• Ability to apply first principles thinking to solve problems and make decisions in uncertain or ambiguous situations.

• Background in highly regulated industries (e.g., nuclear, aerospace, aviation, maritime).

Desired Qualifications & Skills:

• Prior experience working as an operator in nuclear environments (e.g., nuclear energy, naval reactors, or radiation-controlled facilities), with familiarity in safety protocols, regulatory compliance, and high-reliability operations

• Licensed as a Senior Reactor Operator or Naval equivalent.

• Direct experience in developing technical procedures, human factors engineering, or operational interface design.

• Prior operations background such as mission control room operator.

• Experience with human factors and user-centered instructions for operational workflows.

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.

• Willingness to travel 50% - 60% of the time, as needed for projects.

• 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: [email protected].
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.