Engineer IV-V Mechanical Systems Design Engineer

Engineer IV-V Mechanical Systems Design Engineer at X-energy

X-energy LLC conducts a thorough recruiting process and will never issue offers without an interview to discuss qualifications and responsibilities. All applications will be submitted via our company career page at  We will never ask you to provide payment information as part of the recruiting process. If anyone claiming to represent X-energy directs you in a manner otherwise, please contact us at

X-energy is seeking professionals with 10+ years of hands‑on experience designing, manufacturing, integrating, and testing mechanical systems, assemblies, and components to join the Nuclear Auxiliary Systems Prototype Development team as a Mechanical Systems Design Engineer. The role is responsible for the engineering design, integration, and commissioning of specialized testbeds used for testing prototype designs to reduce risk and advance Technology Readiness Level (TRL).

In addition to testbed development, you will also play a key role in evaluating the performance of prototype designs to facilitate rapid iteration of the design, build, and testing process.

• Lead the engineering design, integration, and commissioning of mechanical testbeds.
• Collaborate with cross‑functional teams to evaluate prototype performance and support iterative improvement.
• Drive risk reduction and technology readiness through hands‑on testing and analysis.

• 10+ years of experience in mechanical systems design and testbed development.
• Strong background in manufacturing, integration, and testing of mechanical assemblies.
• Proficiency with design and simulation tools relevant to mechanical engineering.

• Mid‑Senior level

• Full‑time

• Engineering and Information Technology

• Nuclear Electric Power Generation