Principal Power Systems Engineer

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.

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, turbo machinery, 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.

Responsibilities & Duties:

• 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.

Required

Qualifications & Skills:

• 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.

Desired

Qualifications & Skills:

• M.S. in Electrical Engineering or related discipline.
• Experience in power electronics development for high-power,…