Senior Mechanical Engineer

AdAstra Talent Advisors; Los Angeles (CA); On-site; USD 120,000 - 170,000; Full time

Benefits offered by this job

Ground-floor equity

Discretionary bonus

Employee stock purchase plan

Job summary

AdAstra Talent Advisors seeks a Senior Mechanical Engineer to design, analyze, and build reactor hardware for a turnkey manufacturing line. You’ll own structures, components and fluids subsystems from sketch to flight-ready hardware, guiding teams and shaping the technical bar in a fast-paced environment.

You will lead trade studies, validate engineering decisions from first principles, and collaborate with factory teams to scale production of high-reliability hardware.

Qualifications

• 5+ years designing, analyzing and building mechanical hardware for complex systems.
• Ability to run trade studies and make principled calls with incomplete data.
• Hands-on experience with fluid, gas or thermal systems.
• Bachelor’s in mechanical engineering or related field.

Responsibilities

• Own design, analysis and testing of pressure vessels, containment and related components.
• Lead cross-functional reviews and mentor engineers.
• Support assembly in the factory and drive manufacturing scalability.
• Develop and validate valves, regulators, and heat exchangers.

Skills

Mechanical design

Technical leadership

Trade studies

First principles

Thermal systems

Education

Bachelor's in Mechanical Engineering

Tools

ASME BPVC

Weld qualification

Job description

Senior Mechanical Engineer — Reactor Hardware

Structures · Components · Fluids | Full Time | Los Angeles Area (onsite)

The Problem

The world needs more electricity than it can currently make, and the gap is widening fast. AI data centers are the clearest example: they now account for more than half of all growth in US power demand, and the grid was not built for it.

Our client's answer is fission. Not the kind that takes a decade and a construction crew, but a small reactor designed to be manufactured on a line. That one decision changes everything downstream, because every part has to be designed for tooling, lead time and assembly from the first sketch.

The hardware is being designed, built and tested in-house right now.

What You'll Own

Three seats. Same bar, different hardware. Take one, or a combination if your background leans towards two.

Structures — pressure vessel, containment, seismic isolation. Material trade studies across cost, mass, strength and corrosion, then proving it out through thermal and pressure cycling, shock, vibe and embrittlement testing. ASME BPVC, large forgings, weld qualification.

Components — valves, regulators, solenoids, control-rod drive mechanisms, heat exchangers. Design through analysis, production layout, assembly, environmental test and reactor integration. Delete the part, simplify the rest, then automate the build.

Fluids — the whole piping and plumbing network. Tightly packaged, ultra-high reliability, genuinely awful access, and a cost target. You do the analysis, then work the build shop to scale your own manufacturing line.

All three: you support assembly in the factory and watch your hardware get built. You also set the technical bar for the engineers who join behind you.

The Bar

• 5+ years designing, analyzing and building mechanical hardware. Analysis that never became a part is not what this team needs.
• You've led technically: scoped work, reviewed other people's designs, got engineers to good outcomes.
• You can run a trade study and make a call from first principles with incomplete information.
• Hands-on with fluid, gas or thermal systems.
• Bachelor's in mechanical engineering or similar.

Nuclear experience is not required.

Some of the strongest people in this space came from launch vehicles, naval propulsion, semiconductor equipment and motorsport. If you hit most of this, apply.

Nice to Have

ASME BPVC design, forging and weld qual, high-pressure systems, test instrumentation (transducers, thermocouples, RTDs, solenoid valves), electromechanical actuators and flow control hardware, or highly integrated fluid systems in high-reliability environments.

Logistics

Los Angeles area, full time onsite. The hardware is in the building.

What Success Looks Like

A year in, hardware you designed is in the pilot reactor, the test data behind it is yours, and a junior engineer on your team runs a trade study the way you taught them.

• Ground-floor equity, with real upside
• Discretionary bonus and an employee stock purchase plan

Our client is an equal opportunity employer. All qualified applicants receive consideration without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, veteran status, or any other protected characteristic.