Senior Mechanical Engineer

Senior Mechanical EngineerHexium 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.RoleWe'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.Key ResponsibilitiesReview and assess legacy AVLIS mechanical designs and technical records at a DOE national laboratory, working within required classified-handling proceduresOwn mechanical design of chamber and vacuum systems, including all system interfacesApply vacuum system design to materials compatibility selection, outgassing mitigation, and contamination controlConvert legacy designs into modern 3D CAD assemblies and validate them via thermal/structural simulationWork directly with national laboratory scientists and engineers to close technical design gapsCollaborate with Hexium's Integration Team on prototype procurement and testing requirementsQualify vacuum suppliers and custom equipment fabricatorsDefine facility and utility interface requirements for prototype and pilot systemsPartner with Nuclear Safety on design complianceRequired Qualifications6+ years of mechanical engineering experience, including vacuum system design and/or precision mechanical hardwareBachelor's degree in Mechanical Engineering or closely related fieldProficiency 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 monthsMust 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 progressesPreferred QualificationsExperience with specialty alloys and refractory metal fabricationExperience with high-temperature vacuum processesFEA/thermal simulation experienceBackground in safety-critical hardware (aerospace, nuclear, defense)Physical RequirementsExtended periods reviewing physical archival documents and fine-detail technical drawings, requiring sustained close visual focusFine motor skills and dexterity for precision component assembly and inspectionAbility to work in confined spaces around vacuum hardwareOccasional lifting up to 50 lbsExtended periods standing/moving within a lab environmentWork EnvironmentOn-site at a DOE national laboratory in Livermore, CA, with standard site security and classified-handling protocols. Role will transition to a separate Hexium production facility as the program scales.BenefitsStock OptionsPaid Time Off401(k) MatchingMedical, Dental, Vision insuranceHSA & FSAsE-Verify: Hexium Inc. participates in E-Verify. All new hires are required to complete the I-9 employment eligibility verification form and provide documentation to confirm their identity and authorization to work in the United States.Screening: Employment is contingent upon successful completion of a background check.