Mechanical Design Engineer

Job Description

X-energy is seeking professionals to join its Mechanical Engineering team in the role of Mechanical Design Engineer supporting the development of the Xe-100. This role is responsible for the engineering design and development of mechanical systems, structures, and components such as Reactor Internal Structures, Steam Generator System, Helium Circulator System, Graphite Core Components, Reactor Cavity Cooling System, or Nuclear Auxiliary Systems.

The work includes concept development, analysis of designs, prototyping, testing, and commissioning to meet all technical specifications and requirements.

• Develop mechanical/physical concepts, design, and support development of processes to create or identify structures, systems, and components (SSCs) for use in nuclear products or facilities with a focus on nuclear safety.
• Identify, collect, and document applicable requirements, interfaces, design basis, and criteria by coordinating with key stakeholders and systems engineers, and support identification of applicable industry codes and standards.
• Plan and perform the analysis required to assess aspects of the SSCs to ensure they can perform their intended functions and meet technical specifications and design requirements.
• Perform computations utilizing hand calculations and analytical tools for structural, thermal, hydraulic, and other scoping calculations as required at the direction of project leads and systems engineers.
• Develop innovative mechanical solutions to refine and deploy concepts, technologies, and designs associated with X-energy developed reactors, including pressure vessels, piping, reactor internals, nuclear fuel, and high temperature materials such as graphite.
• Integrate design activities across engineering team members, partners, and suppliers and perform supporting scoping and sizing calculations to down select design features to meet design requirements using guidance from consensus codes and standards.
• Create and maintain CAD-generated engineering models of reactor SSCs.
• Support the assessment of SSCs for manufacturability as well as assembly and integration considerations at the direction of project leads.
• Write and develop design documentation including design basis documents, technical reports, calculations, and drawings in accordance with applicable procedures.
• Develop Verification and Validation (V&V) plans for analytical tools and support qualification of the toolset.
• Perform work in accordance with X-energy quality procedures for design and configuration management to ensure project quality requirements are met.
• Provide independent reviews and acceptance reviews of engineering deliverables and data.
• Maintain professional demeanor and behavior at all times in all forms of communication.
• Perform other duties as assigned by manager.

• Bachelor’s degree in mechanical engineering or related engineering discipline (e.g., nuclear aerospace, chemical).
• Proficiency with engineering hand calculations.
• Experience designing and developing mechanical or fluid systems, assemblies, or components.
• One plus year of demonstrated hands‑on experience developing and delivering hardware or manufacturing processes in a production environment.
• Experience in use of Computer-Aided Design (CAD) and product lifecycle management (PLM) software (e.g., UG/NX, Solid Works, Pro‑Engineer, Teamcenter, Windchill).

• Experience with commercial nuclear power plant operations.
• Professional experience with ASME Boiler & Pressure Vessel Code (BPVC) Section III and/or Section VIII.
• Experience with NRC regulations and licensing requirements for safety‑related systems.
• Experience with ASME BPV Code, ASME B31.1 or B31.3, and other industry standards.
• Experience with mechanical process equipment (piping, ducting, HVAC, fire suppression, pumps, pressure vessels).
• Hands‑on experience with graphite or other non‑metallic components, fabrication or assembly sequencing, and/or tooling development.
• Experience with procurement and manufacturing oversight of pressure vessels or large metallic components.

LevelII

• Support team members with the execution of…