Principal Mechanical Design Engineer, Turbomachinery

Radiant Industries•El Segundo, CA

10h•$200,500 - $314,475•Onsite

About The Position

Radiant is seeking a Principal Mechanical Design Engineer, Turbomachinery to serve as the Responsible Engineer for turbomachinery within its nuclear-driven power generation system. The role owns the mechanical design, integrity, and performance of the core rotating assembly in a 1 MW closed-loop Brayton cycle. The engineer 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, the role sets direction for rotor dynamics, structures, bearings, seals, and system integration while working closely with electrical, thermal, manufacturing, and test teams. It is a hands-on, high-ownership position focused on technical excellence, sound engineering judgment, and delivering reliable, production-ready turbomachinery. The position is 100% onsite at Radiant’s El Segundo headquarters. Extended hours and weekends may be necessary to accomplish the mission. Radiant describes its full-time new-hire compensation package as including base salary, substantial equity grants, and comprehensive health benefits; compensation and level depend on interview performance, experience, education, and qualifications. No salary range is specified.

Requirements

B.S. in Mechanical Engineering or a related field.
10+ years of experience designing high-speed rotating machinery, such as turbines, compressors, or similar systems.
Deep expertise in structural analysis and mechanical design of turbomachinery.
Experience with bearings, seals, and high-speed shafting design.
Expert-level proficiency with analysis tools such as ANSYS, and advanced use of NX and Teamcenter for complex design, simulation, and product lifecycle management.
Strong understanding of tolerancing, GD&T, and precision mechanical assembly.
Experience owning hardware through design, build, and test cycles.
Hands-on experience with assembly, integration, and troubleshooting of turbomachinery.
Strong system-level thinking and mechanical intuition.
Excellent engineering judgment and decision-making capability.
Ability to influence without authority across cross-functional teams.
Clear communication skills, including the ability to explain complex technical concepts.
High ownership mindset and accountability for hardware outcomes.
Ability to operate effectively in a fast-paced, first-of-a-kind development environment.
Willingness to work extended hours and weekends as necessary.
Must work 100% onsite at the El Segundo headquarters.

Nice To Haves

Experience with closed-loop Brayton cycle systems or similar energy systems.
Familiarity with high-temperature materials and extreme-environment design.
Experience integrating mechanical systems with high-speed electric machines.
Prior experience as a Responsible Engineer for complex hardware.
Experience scaling hardware from prototype to production.

Responsibilities

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 thermal, structural, and operational constraints.
Make technical decisions on rotor layout, shafting, bearings, seals, materials, and clearances.
Ensure designs meet performance, reliability, safety, and regulatory requirements; establish standards for design rigor, analysis quality, and documentation.
Lead detailed design of turbomachinery components, including rotors, shafts, housings, and support structures.
Test and validate turbomachinery, correlating models, reducing risk, and verifying performance.
Perform and review structural and thermal analyses for high-speed, 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.
Coordinate with turbomachinery aero, motor design, thermal, manufacturing, and test teams to integrate turbine, compressor, and alternator subsystems.
Drive interface definitions across mechanical, electrical, and thermal boundaries.
Collaborate with manufacturing to ensure designs are producible, inspectable, and scalable; engage suppliers on critical components and design decisions.
Support assembly, integration, and testing of turbomachinery hardware.
Define validation strategies, including spin testing, thermal testing, and system-level operation.
Lead root-cause analysis and design iteration for test failures or performance gaps; participate hands-on in hardware bring-up, troubleshooting, and refinement.
Provide subject-matter expertise and technical guidance and design reviews without direct people-management responsibility.
Influence engineering direction and contribute to the technical roadmap, risk identification, and mitigation strategies.

Benefits

Substantial incentive stock plan for full-time employees.
Medical coverage up to the base silver-level plan at 100% for employees and 50% for dependents, with plans available up to Platinum.
Sponsored One Medical memberships for employees and their dependents.
Top-tier vision plan coverage at 100% for employees and 50% for dependents.
Top-tier dental plan coverage at 100% for employees; orthodontia is extra, and dependent coverage is 50%.
Voluntary life, accident, hospital, and critical illness insurance, plus commuter benefits and FSA/HSA, offered as employee-contributed benefits.
Eight weeks of paid parental leave for all parents and additional paid pregnancy leave for California employees.
Nuclear Engineering Certificate Program with Penn State University, fully covered for eligible employees.
Daily catered lunch, free snacks, and drinks.
Flexible PTO policy and remote-workday allocation.
Company and team-bonding events and happy hours.