Principal Power Systems Engineer

Radiant is an El Segundo, CA-based company building the world's only mass-produced, transportable nuclear microreactors. The U.S. grid is under growing strain, with power demand accelerating, driving higher utility costs, rising carbon emissions, and interconnection backlogs. Radiant has a solution, transportable, on-site power. Our first reactor, Kaleidos, is 1 megawatt: small enough to be factory-built, transported by land, sea, or air, and deployed wherever power is needed. 1 MW can power 1000 homes for five years. Ship it back and we refuel for a 20 year operating life. We made energy a product that can be used for critical infrastructure like military bases, data centers, hospitals, and remote sites, as well as the commercial main street businesses that keep America running. Founded in 2020, Radiant is under contract to deliver power to the U.S. Army, Navy and Air Force and has signed pre-order agreements with Equinix, with deployments beginning in 2028.

Radiant is seeking a talented Principal Power Systems Engineer to lead the design, modeling, and validation of electrical power systems supporting our nuclear microreactor platform. You will play a critical role in defining how power is generated, conditioned, controlled, and delivered to customers across grid-connected, islanded, and rapidly deployable environments.

In this role, you will own power system studies from early architecture tradeoffs through detailed modeling, testing, and system validation. You’ll collaborate closely with electrical design, controls, turbomachinery, nuclear, thermal, and software teams to ensure safe, stable, and reliable power delivery under a wide range of operating and contingency conditions. This role is central to commercializing Earth’s first mass-produced portable nuclear reactors.

• Own power system architectural design for microreactor-based power generation systems operating in grid-connected and islanded modes.

• Develop single-line diagrams of the power system for single- or multiple-reactor configurations.

• Develop FMEAs to identify system behavior during component/system failures and identify redundancy paths.

• Evaluate system behavior during disturbances such as load steps, faults, breaker operations, and loss-of-generation events.

• Size energy storage systems for reactor cold start and variable load demands.

• Own synchronization of multiple reactors in a microgrid and multiple reactors tied to grid.

• Collaborate cross-functionally with the power conversion team to understand generator requirements and design power systems that can integrate seamlessly.

• Participate in software-in-the-loop (SIL), hardware-in-the-loop (HIL), and system-level testing to validate/verify system performance.

• Support system checkouts, commissioning, and testing of all power requirements

• Regulatory compliance of power systems, including testing methods to verify power quality.

• B.S. in Electrical Engineering with an emphasis in power systems or control systems.

• 5+ years of experience designing power systems for generation, microgrids, or mission-critical power systems.

• Experience with sizing and integrating high-voltage battery systems with power electronics.

• Strong experience with power system modeling and simulation tools (e.g., PSCAD, ETAP, PSS®E, Simulink, or equivalent).

• Solid understanding of inverters, grid converters, DC/DC converters, rotating generation, and power system control modes (grid-forming, grid-following, droop control).

• Experience in analyzing system stability, protection behavior, and fault response in complex electrical systems.

• Ability to clearly communicate technical concepts and results to cross-functional teams.

• M.S. in Electrical Engineering or related discipline.

• Experience in power electronics development for high-power, medium-voltage equipment, including transformers, switchgear, inverters, active rectifiers, DC/DC converters, and generator controls.

• Experience with islanded power systems supporting critical loads.

• Familiarity with interconnection requirements, grid codes, and relevant IEEE or utility standards.

• Experience in modeling dynamic loads and fast-changing electrical demand.

• Exposure to nuclear, aerospace, defense, or other highly regulated industries.

• Experience mentoring junior engineers or leading technical efforts on complex programs.

• Must be willing to work extended hours and weekends as necessary to accomplish our mission.

• Must work 100% onsite at Radiant’s El Segundo HQ.

• 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.

• Nuclear Engineering Certificate Program: 100% covered educational program with Penn State University, for eligible employees, to rapidly upscale into nuclear.

• 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 full-time 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.