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 Principal Turbomachinery Engineer to serve as the Responsible Engineer for the turbomachinery within our nuclear-driven power generation system. This role owns the mechanical design, integrity, and performance of the core rotating assembly at the heart of our 1MW closed-loop Brayton cycle.

You will define and drive the mechanical architecture of high-speed rotating hardware operating at extreme temperatures, pressures, and rotational speeds. As a deeply technical individual contributor, you will set direction for rotor dynamics, structures, bearings, seals, and system integration while working closely with electrical, thermal, and manufacturing teams.

This is a hands-on, high-ownership role focused on technical excellence, sound engineering judgment, and delivering reliable, production-ready turbomachinery.

Responsibilities & Duties

Technical Ownership & System Architecture

Serve as Responsible Engineer for the turbomachinery mechanical system.

Own the mechanical architecture and design strategy for high-speed rotating assemblies.

Lead rotor dynamics, structural integrity, and life analysis for rotating components and assemblies.

Define and flow down requirements from system-level constraints including thermal, structural, and operational environments.

Make key technical decisions on rotor layout, shafting, bearings, seals, materials, and clearances.

Ensure designs meet performance, reliability, safety, and regulatory requirements.

Establish and uphold standards for mechanical design rigor, analysis quality, and documentation.

Mechanical Design & Analysis

Lead detailed design of turbomachinery components including rotors, shafts, housings, and support structures.

Test and validate turbomachinery, driving model correlation, risk reduction, and performance verification.

Perform and review structural and thermal analysis to ensure integrity under high-speed and high-temperature operation.

Define tolerances, fits, stack-ups, and alignment strategies for precision rotating assemblies.

Partner with electrical engineering on alternator integration, including electromagnetic and structural coupling.

Cross-Functional Integration

Partner closely with turbomachinery aero, motor design, thermal, manufacturing, and test teams.

Ensure seamless integration between turbine, compressor, and alternator subsystems.

Drive clear interface definitions across mechanical, electrical, and thermal boundaries.

Collaborate with manufacturing to ensure designs are producible, inspectable, and scalable.

Engage with suppliers on technically critical components and design decisions.

Prototyping, Testing & Validation

Support assembly, integration, and test of turbomachinery hardware.

Define validation strategies including spin testing, thermal testing, and system-level operation.

Lead root cause analysis and drive design iteration for test failures or performance gaps.

Remain hands-on in hardware bring-up, troubleshooting, and refinement.

Technical Influence

Act as a subject matter expert in turbomachinery mechanical design and rotating systems.