Principal Nuclear Mechanical Engineer
Confirmed on the employer's own hiring board on Oct 22, 2026. First seen by Alion on Sep 17, 2026.
About the Role
As a Nuclear Mechanical Engineer, you'll own components for our primary system and reactor internals from concept through qualification. You'll turn thermal-hydraulic requirements into mechanical designs, size and specify hardware, and build the NX CAD models and drawings needed to fabricate it. You'll also prove your own designs out: planning and running test campaigns, gathering data, and qualifying components to the codes and quality standards nuclear hardware demands. You'll work directly with vendors capable of nuclear-grade fabrication, then feed what you learn from test and build back into the next design iteration. This is a hands-on role for a mid-level engineer ready to own components independently, equally comfortable at the CAD workstation, on the vendor floor, and at the test bench in a marine, radiological environment.
Responsibilities
Own mechanical design of primary system and reactor internal components, from concept through detailed design.
Translate thermal-hydraulics analysis into component specifications, sizing, and design decisions.
Build and maintain NX CAD models and generate the drawings and specifications required for fabrication, including GD&T call-outs.
Plan and run experimental test campaigns to qualify your own designs, including test plans, procedures, and data acquisition.
Qualify components to relevant nuclear codes and standards, such as the ASME Boiler and Pressure Vessel Code, Section III, and applicable quality requirements.
Engage and manage vendors capable of nuclear-grade fabrication, from RFQ through receiving inspection.
Design with the marine and radiological environment in mind: vibration, shock, thermal cycling, corrosion, radiation exposure, and tight volumetric constraints aboard a vessel.
Drive root-cause investigations when hardware doesn't perform as designed, and iterate the design accordingly.
Required Qualifications & Skills
Bachelor's degree in Mechanical Engineering, Nuclear Engineering, or a related field.
3+ years of mechanical design experience, including components taken from concept through fabrication.
Hands-on experience with CAD and drawing generation, including GD&T.
Experience planning and executing hardware test campaigns, from test plan through data acquisition and reporting.
Familiarity with nuclear codes and standards such as ASME Section III, or a demonstrated ability to quickly get up to speed on regulated hardware requirements.
Comfort working directly with vendors and fabricators to get nuclear-grade hardware built right.
A pragmatic, curious, low-ego approach to problem-solving.
Desired Qualifications & Skills
Direct experience with ASME Section III, NQA-1, or other nuclear quality programs.
Experience with FEA or first-principles hand calcs to inform design.
Familiarity with marine, nuclear, aerospace, or other regulated hardware environments.
Experience shepherding a part from design → fab → test → iteration in a fast-moving environment.