Senior Mechanical Engineer

Thanks for your interest in Oklo! We are searching for a Sr. Mechanical Engineer to join our fuel recycling engineering team within Oklo's Recycling Division.

Position Description

You will serve as Oklo's technical expert for high-temperature process piping, pressure vessels, and pressure-retaining components supporting the Oak Ridge Fuel Recycling Facility (OFRF). You will own the mechanical design basis, analysis, code compliance, and technical interfaces for these systems from early design through fabrication, testing, installation, commissioning, and operational support. The work includes demanding hot-cell, molten-salt, inert-atmosphere, vacuum, and thermal-cycling service conditions.

This role is for a technically rigorous mechanical engineer who is comfortable working from first principles, developing and reviewing detailed analytical models, and owning mechanical equipment designs from early concepts through fabrication, testing, hot-cell installation, and operation. Success requires strong engineering judgment, hands-on design capability, clear communication, and the ability to balance technical performance, safety, remote maintainability, manufacturability, schedule, and cost in a fast-moving environment.

Specific responsibilities may include:

• Serve as Oklo's technical expert for high-temperature piping, pressure vessels, pressure boundaries, and their supporting components within the OFRF.

• Translate process temperatures, pressures, chemistry, flow conditions, vacuum and inert-gas requirements, operating cycles, and upset conditions into the piping and vessel design basis, applicable codes, load combinations, service life, and acceptance criteria.

• Perform and review piping stress and flexibility analyses for sustained, thermal, pressure, seismic, displacement, and other applicable loads, including equipment nozzle loads and support reactions.

• Perform and review pressure vessel analyses for internal and external pressure, local loads, nozzle loads, thermal gradients, buckling, fatigue, creep, and cyclic service, including design-by-analysis when appropriate.

• Perform and review steady-state and transient thermal analyses addressing heat loss, insulation, heat tracing, temperature gradients, heat-up, cooldown, and abnormal thermal conditions.

• Select and qualify materials for high-temperature and corrosive service, considering molten-salt compatibility, oxidation, thermal aging, creep, fatigue, radiation exposure where applicable, weldability, and fabrication constraints.

• Design and review vessels, piping, nozzles, flanges, closures, transitions, supports, anchors, restraints, expansion joints, bellows, penetrations, and other pressure-boundary components.

• Define piping layout, support, restraint, slope, drainability, isolation, inspection, and access requirements needed to manage thermal expansion and support safe operation and maintenance.

• Coordinate piping and vessel interfaces with process equipment, hot-cell penetrations, confinement boundaries, structures, utilities, and instrumentation; incorporate remote connection, inspection, isolation, removal, and replacement provisions where personnel access will be limited.

• Develop and review calculations, specifications, piping material classes, line lists, vessel data sheets, drawings, fabrication details, and technical requirements.

• Review supplier and subcontractor calculations, models, drawings, material selections, weld details, fabrication procedures, and inspection plans; provide technical direction and resolve piping and vessel design issues.

• Establish fabrication and quality requirements, including material traceability, welding, heat treatment, dimensional control, nondestructive examination, pressure testing, leak testing, and final acceptance.

• Develop procurement specifications, statements of work, technical bid evaluations, and supplier acceptance criteria for piping and vessel packages.

• piping and vessel input to design reviews, failure-mode and constructability evaluations, engineering changes, supplier deviations, nonconformances, requests for information, and field changes.

• Support commissioning, troubleshooting, and root-cause evaluations involving high-temperature piping, pressure vessels, and pressure boundaries.

• Mentor other engineers and provide technical leadership in high-temperature piping and vessel design, analysis, materials, fabrication, and engineering judgment.

Minimum Qualifications:

• Bachelor's degree in Mechanical Engineering or a related engineering discipline.

• 10+ years of mechanical engineering experience with process piping, pressure vessels, or high-temperature systems, including responsibility for piping stress, pressure vessel, thermal, or mechanical stress analyses.

• Working knowledge of applicable ASME codes and standards, including ASME B31.3 and ASME Boiler and Pressure Vessel Code Section VIII.

• Strong understanding of thermal expansion, fatigue, creep, buckling, nozzle loads, pipe supports, pressure boundaries, and elevated-temperature material behavior.

• Experience developing and reviewing calculations, specifications, data sheets, drawings, and fabrication-ready design packages.

• Experience with materials selection, welding, fabrication, nondestructive examination, pressure testing, and inspection of piping or vessels.

• Ability to independently evaluate analytical results, code compliance, design assumptions, failure modes, and technical margins.

• Experience coordinating piping and vessel interfaces with process, structural, equipment, instrumentation and controls, operations, and supplier teams.

• Strong technical writing, communication, and engineering judgment.

• Eligibility to work in the United States without sponsorship.

Bonus Qualifications:

• Master's degree or Ph.D. in Mechanical Engineering or a related technical discipline.

• Professional Engineer registration or the ability to obtain Tennessee licensure.

• Experience with molten-salt, inert-gas, vacuum, nuclear hot-cell, or fuel-cycle systems and with elevated-temperature or corrosion-resistant alloys.

• Experience with ASME Section VIII Division 2, design-by-analysis, fatigue, buckling, creep, seismic qualification, or coupled thermal-mechanical analysis.

• Experience with analysis tools such as CAESAR II, AutoPIPE, ANSYS, Abaqus, COMPRESS, PV Elite, Mathcad, or similar software.

• Experience overseeing piping or vessel fabrication, supplier quality, weld qualification, nondestructive examination, and acceptance testing under nuclear quality assurance and design control processes.

Competencies

We are looking for a Sr. Mechanical Engineer who is:

• Technically rigorous: Comfortable working deeply in thermal analysis, stress analysis, equipment design, materials, codes, and failure modes.

• Analytically strong: Able to develop sound assumptions, understand model limitations, and determine whether calculated results make physical sense.

• A practical equipment designer: Comfortable moving between calculations, CAD models, drawings, fabrication details, testing, and physical hardware.

• Focused on hot-cell operability: Understands that