About Radiant

Radiant is an El Segundo CA-based startup building the worlds first mass-produced portable nuclear microreactors. The companys 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. Radiants 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 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. Youll 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 Earths first mass-produced portable nuclear reactors.

Responsibilities and 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 Skills and Qualifications:

• 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 PSSE 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 Skills and Qualifications:

• 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

Additional Requirements:

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

• Must work 100% onsite at Radiants El Segundo headquarters

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. Radiants 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 todays advanced reactor builders dont wait for job postings. They join the winning team. If thats you contact us directly for immediate opportunities: .

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.

Unfortunately we are unable to provide visa sponsorship at this time.

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

Required Experience:

Staff IC