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

About the Role

Radiant is seeking a Principal Electrical Engineer, HIL to lead the electrical system architecture and test infrastructure for Kaleidos, our commercial microreactor targeted for deployment in 2028.

You will own end-to-end electrical integration, from architecture and requirements definition through hardware bring-up, testing, and commissioning, and lead the development of Hardware-in-the-Loop (HIL) systems and the broader test environment that validates the reactor before it reaches the field.

As the technical authority across electrical integration and validation strategy, you will set direction independently while collaborating across mechanical, software, and systems engineering. You will define the electrical architecture behind the first commercialized portable microreactor as we begin deploying to our customers in 2028.

Responsibilities & 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, establishing it as a foundational asset for validating the commercial unit ahead of 2028.
• Define and own 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 protocol selection, timing, and fault behavior at the boundaries.
• Define and drive the electrical validation strategy, developing the test procedures and methodologies the program depends on.
• Own schedule, budget, and vendor management for electrical hardware and integration activities.
• Drive automation and tooling improvements, with real influence over how the team tests.
• Lead design reviews and carry technical decisions to stakeholders across electrical integration, embedded, software, and controls.

Required Qualifications & Skills

• BS in Electrical Engineering, Mechanical Engineering, Computer Engineering or a related discipline.
• 8+ years of progressive engineering experience across hardware, controls, or test systems, with hands-on design, integration, and validation.
• 5+ years developing hardware-in-the-loop (HIL) systems, including signal conditioning, DAQ/IO interfaces, plant model integration, and embedded controls validation.
• Demonstrated experience setting technical direction, mentoring engineers, and driving programs with significant scope and ambiguity.
• Proven ability to deliver a functional product that meets requirements under tight timelines.
• Experience with DAQ and test systems (NI PXI, dSPACE, Speedgoat, or similar), including test execution and validation frameworks.
• Proficiency with test software and scripting environments (LabVIEW, TestStand) and at least one programming language (Python, C++, C#, or similar).
• Strong electrical and software debugging and root cause analysis skills.
• Experience working cross-functionally with software, mechanical, and systems engineering teams.
• Background in high-reliability, safety-critical, or regulated environments (aerospace, defense, nuclear, medical, or automotive).

Desired Qualifications & Skills

• MS in Electrical Engineering or a related discipline.
• Familiarity with real-time simulation systems and/or FPGA-based hardware.
• Experience with controls fundamentals and software testing processes.
• Hands-on experience with trace capture, data acquisition, and analysis tools.

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 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:.

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.