Mechanical Engineer (Nuclear / Reactor Systems)

About the role:

Applied Atomics is seeking a Mechanical Engineer to design, develop, and develop the high-reliability mechanical systems that support our reactor product. You will work on hardware such as precision motion systems, actuation mechanisms, structural components, safety-related assemblies, and complex mechanical interfaces within the reactor and adjacent systems. This role blends mechanical engineering fundamentals with the unique environmental and reliability needs of a nuclear system. Prior nuclear experience is not required; we are looking for strong mechanical engineers who can design robust hardware, solve complex problems, and iterate rapidly alongside world-class nuclear engineers.

This role is ideal for someone who wants broad responsibility, thrives in a fast-paced hardware environment, and wants to make a lasting impact on the design of a first-of-a-kind (FOAK) nuclear power system.

Why we need you

We are transitioning nuclear energy from a theoretical science into a practical reality, and that requires practical problem-solvers. We need engineers who are eager to take direct responsibility for their work and see it through to completion. Your role will be critical in transforming complex designs into safe, reliable, and operational power plants that will operate for decades to come.

What you will do

Mechanical System Design

* Design and develop mechanical systems and components for the reactor environment, including motion systems, actuators, linkages, structural components, and safety-related mechanical assemblies.
* Support the development of hardware used in reactivity control, mechanical actuation, and system-level motion interfaces.
* Conduct design trade studies, concept development, and material selection.

Analysis & Engineering Fundamentals

* Perform structural and thermal analysis using hand calculations and finite element analysis tools (ANSYS, Abaqus, Nastran, etc.)
* Conduct tolerance stack-ups, GD&T applications, and precision mechanical alignment studies.
* Evaluate fatigue, wear, friction, vibration, and reliability performance.

Build, Assembly, & Testing

* Create manufacturing, assembly, and integration instructions.
* Develop and execute test plans for components and assemblies.
* Support hardware bring-up, test execution, failure analysis, and design iteration.

Supplier & Manufacturing Interface

* Identify and work with suppliers for machined parts, actuators, bearings, materials, and assemblies.
* Ensure components meet dimensional, functional, and reliability requirements.
* Support design-for-manufacturability and design-for-assembly reviews.

Cross-Functional Collaboration

* Work closely with nuclear engineers, thermal-fluids engineers, materials engineers, and systems engineering.
* Ensure mechanical designs align with nuclear safety, reliability, and performance requirements.
* Contribute to system-level integration across reactor subsystems.

Additional Responsibilities

* Take end-to-end responsibility for your projects, from initial concepts through to deployment and ongoing operations
* Partner closely with our multidisciplinary team of experienced engineers to tackle complex, cross-functional challenges
* Deliver high-quality work steadily and safely, ensuring every solution meets our rigorous quality standards while also for solving scalability issues in the future
* Continually improve our internal engineering processes, documentation, and tools to support the team as we scale

What you bring to the table

Need to haves:

* Bachelor’s degree in Mechanical Engineering or related field.
* 4+ years of experience designing mechanical systems or precisions hardware (2+ years w/ MS).
* Proficiency in mechanical analysis, including hand calcs and FEA (ANSYS, Abaqus, FEMAP, etc.).
* Experience with CAD tools (NX, SolidWorks, Creo, etc.).
* Demonstrated understanding and application of GD&T.
* Demonstrated hardware ownership from concept --> detailed design --> build --> test --> iteration.
* Ability to operate across multiple cross-functional teams.
* Strong written and oral communication skills; able to explain complex topics simply.
* Self-starter, ownership mentality, and ability to drive tasks from concept to completion

Nice-to-haves:

* Master’s degree in Mechanical Engineering or related field.
* Experience designing hardware that has been manufactured, deployed, and iteratively improved.
* Experience with electromechanical components (motors, solenoids, encoders, drives).
* Exposure to high-temperature, radiation, vacuum, or high-vibration environments (energy, aerospace, defense, robotics).
* Knowledge of relevant regulatory standards (ASME, NRC regs., 10 CFR 50, etc.).
* Prior experience with FOAK (first-of-a-kind) or advanced reactor development programs.

BENEFITS & PERKS FOR ELIGIBLE EMPLOYEES

* Substantial incentive stock plan for all full-time employees.
* Medical / Vision / Dental (details forthcoming).
* Flexible PTO policy.
* Hybrid and remote work options depending on role.
* Other benefits to be announced at offer stage.

We are an equal opportunity employer, and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law. We are unable to provide visa sponsorship at this time. 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.

Remote pay range
$138,342—$195,322 USD