Senior Mechanical Engineer

Hexium•Livermore, CA

21h•Onsite

About The Position

Hexium is modernizing Atomic Vapor Laser Isotope Separation (AVLIS), a laser-based isotope enrichment technology originally developed and demonstrated at Lawrence Livermore National Laboratory (LLNL). We are advancing AVLIS into a scalable, industrial-grade enrichment platform designed to strengthen domestic energy infrastructure, industrial resilience, and national security. We're hiring a Senior Mechanical Engineer to lead the translation of decades of AVLIS research and development into modern, manufacturable hardware. Initially based on-site at Lawrence Livermore National Laboratory (LLNL) in Livermore, CA, you'll work through legacy technical records to identify the most relevant mechanical designs, reconstruct them as modern 3D assemblies, and identify gaps requiring further engineering. You'll collaborate with national laboratory scientists and engineers as needed to resolve technical questions and inform the modernized design. From there, you'll advance designs through simulation, prototype hardware, and test fixtures, while serving as a mechanical design authority for Hexium's initial prototype and pilot systems. This is foundational engineering work that will bridge national laboratory R&D with the systems needed to advance AVLIS toward commercial application. As the program progresses, this role will transition to a Hexium production facility and will require relocation.

Requirements

6+ years of mechanical engineering experience, including vacuum system design and/or precision mechanical hardware
Bachelor's degree in Mechanical Engineering or closely related field
Proficiency in 3D CAD (SolidWorks, Creo, or similar)
Must currently hold an active DOE Q clearance or active DOD Top Secret clearance, or have held DOE Q / DOD Top Secret clearance within the past 18 months
Must be a U.S. Person (required for access to export-controlled technical data)
Willingness to work on-site full-time at Lawrence Livermore National Laboratory initially, with required relocation to Hexium's production facility (location not yet determined) as the program progresses

Nice To Haves

Experience with specialty alloys and refractory metal fabrication
Experience with high-temperature vacuum processes
FEA/thermal simulation experience
Background in safety-critical hardware (aerospace, nuclear, defense)

Responsibilities

Review and assess legacy AVLIS mechanical designs and technical records at a DOE national laboratory, working within required classified-handling procedures
Own mechanical design of chamber and vacuum systems, including all system interfaces
Apply vacuum system design to materials compatibility selection, outgassing mitigation, and contamination control
Convert legacy designs into modern 3D CAD assemblies and validate them via thermal/structural simulation
Work directly with national laboratory scientists and engineers to close technical design gaps
Collaborate with Hexium's Integration Team on prototype procurement and testing requirements
Qualify vacuum suppliers and custom equipment fabricators
Define facility and utility interface requirements for prototype and pilot systems
Partner with Nuclear Safety on design compliance