Principal Electrical Engineer, Integration & Test

About Radiant Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. Rising energy demand is straining the U.S. grid and driving up utility costs, emissions, and interconnection backlogs. Radiant decentralizes energy, producing power close to where it’s used. Its first reactor, Kaleidos, is a factory-built, 1-megawatt, fail-safe microreactor that can be transported by land, sea, or air and runs up to 5 years without refueling.

Deployed locally without a decade-long build or permitting fight, Kaleidos provides independent power for critical infrastructure like military bases, data centers, hospitals, and remote sites. Founded in 2020, Radiant is under contract to deliver power to the U.S. Army, Air Force, Navy, and has pre-order agreements with Equinix, with deployments beginning in 2028.About the Role Radiant is seeking a Principal Electrical Engineer 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 or a related discipline from an accredited institution.
8+ years of progressive electrical engineering experience, including hands-on hardware design, integration, and test.
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, Test Stand) and at least one programming language (Python, C++, C#, or similar).Strong electrical and software debugging and root cause…