Senior Electrical Engineer, HIL (hardware-in-the-loop)

About Radiant

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.

About the Role

Radiant is seeking a Senior Electrical Engineer, HIL to lead the design, build, and maintenance of Radiant’s electrical test infrastructure for Kaleidos, our commercial microreactor targeted for deployment in 2028. You will own test infrastructure development, including Hardware-in-the-Loop (HIL) systems and other electrical test platforms, and drive integration and validation across critical systems. This role suits an experienced electrical engineer with deep hands-on test-infrastructure expertise, ready to own technical decisions across electrical integration, validation strategy, and test-environment development. You will shape the electrical test infrastructure supporting the first commercialized high-temperature gas-cooled portable microreactor.

Responsibilities and Duties:

• Build the HIL platform from the ground up: plant simulation, real hardware-in-the-loop, and the test environment Kaleidos ultimately ships from.

• Own the design, build, and maintenance of electrical test infrastructure, including test benches and new test platforms as the program scales.

• Define electrical and software integration requirements across power distribution, signal conditioning, sensor mapping, actuator interfaces, and device simulation.

• Own the communication layer between hardware, control systems, and software, including protocol selection, timing, and boundary fault behavior.

• Lead the electrical validation strategy, developing and iterating the test procedures the program depends on rather than executing someone else’s.

• Assemble, debug, and troubleshoot test hardware and harnesses hands-on, with minimal guidance.

• Execute test procedures, collect data, and lead analysis across multiple test environments.

• Drive automation and tooling improvements, with real influence over how the team tests.

• Lead design reviews and carry technical decisions to cross-functional stakeholders.

Required Qualifications & Skills:

• BS in Electrical Engineering or a related field.

• 5+ years of hands-on experience in electrical engineering, including hardware design, integration, and test.

• 3+ years developing hardware-in-the-loop (HIL) systems, including signal conditioning, DAQ/IO interfaces, and fixtures for validating embedded controls

• Demonstrated experience owning and building electrical test infrastructure.

• Proficiency with DAQ and test platforms such as dSpace, NI PXI, Speedgoat, or similar.

• Hands-on experience with data acquisition, test execution, and validation frameworks.

• Strong electrical and software debugging and troubleshooting skills.

• Background in high-reliability, safety-critical, or regulated industry environments (aerospace, defense, nuclear, medical, or automotive).

Desired Qualifications & Skills:

• Experience with real-time simulation systems and FPGA-based hardware.

• Strong understanding of control fundamentals and software testing processes.

• Experience with trace capture tools or data acquisition and analysis tools.

• Comfortable owning multiple test environments and defining new test infrastructure as program needs evolve.

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.

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.

• 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: View email address on jobs.ashbyhq.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.