The TeamThe Numenor team is building Valar's next reactor, the flagship program that will define how we deliver nuclear power at scale. This dedicated team owns the entire plant, from the reactor core and helium systems to cooling, plant modules, and the Citadel, uniting mechanical, systems, safety, IC&E, quality, and supply chain under one mission. The work starts with bringing the first unit to life and ends with a production line that delivers reactors faster with every build. What this team builds will power the critical infrastructure of the future.
The RoleValar Atomics seeks a Senior Process Engineer for the reactor program. This role will own the helium process systems that support the reactor, including helium services, purification, and the systems that interface with the primary helium loop and helium pressure boundary. You will take these systems from concept through design, build, test, and commissioning on the first unit, then help drive them into repeatable, scaled production.
The role demands someone who is hands-on and hardware-first, while bringing the rigor and discipline required to ensure the design basis is met.
Key ResponsibilitiesProcess Design and Analysis
- Own the process architecture and design of helium systems from concept through design freeze.
- Perform process analyses including mass and energy balances, pressure drop, heat transfer, equipment sizing, gas flow, and transient system behavior.
- Develop PFDs, P&IDs, equipment and piping specifications, engineering calculations, and operating procedures.
- Specify and integrate process equipment, including pressure vessels, heat exchangers, adsorption systems, compressors, valves, piping, instrumentation, and gas analyzers.
- Present designs at design reviews and participate in HAZOPs, FMEAs, and system safety analyses.
Build, Test and Commissioning
- Take designs to hardware through technical requirements, vendor selection, proposal review, and approval of manufacturing documentation.
- Lead fabrication oversight, inspections, issue resolution, and acceptance testing with internal manufacturing and suppliers.
- Lead system integration, installation, startup, commissioning, and troubleshooting through first operation.
- Design for manufacture and repeatability, so each unit builds faster than the last.
Collaboration
- Work closely with mechanical, systems engineering, safety, IC&E, quality, and supply chain so the plant design stays integrated.
- Mentor junior engineers and contribute to process engineering standards and best practices.
Basic Qualifications- Bachelor's degree in Chemical Engineering, Mechanical Engineering, Nuclear Engineering, or a related field.
- 5+ years designing industrial process systems, gas handling systems, thermal-fluid systems, or related energy systems.
- Proven track record taking complex engineered systems from concept through build, test, and commissioning.
- Strong foundation in thermodynamics, fluid mechanics, and process engineering principles.
- Experience developing PFDs, P&IDs, process calculations, equipment specifications, and operating procedures.
- Familiarity with industrial instrumentation, process controls, and gas analysis systems.
Preferred Skills and Experience- Master's degree in Chemical Engineering, Mechanical Engineering, Nuclear Engineering, or a related field.
- Helium, cryogenic, high-pressure gas, gas purification, or vacuum systems, including sealing and leak tightness.
- Familiarity with helium coolant chemistry, impurity control, moisture management, graphite compatibility, and gas sampling.
- First-of-a-kind system experience in aerospace, power generation, oil and gas, chemical processing, or defense.
- Working knowledge of ASME pressure vessel and piping codes (Section VIII, B31.3) and industrial gas handling standards.
- Design for manufacture and scaling from prototype to series production.
- Nuclear industry experience, including HTGRs or other advanced reactors: commercial, defense, or national laboratory. A plus, not a prerequisite.
What We Offer- Competitive base salary
- Equity ownership in a rapidly growing advanced energy company
- Comprehensive medical benefits
- Unlimited PTO
- Free daily lunch and dinner provided onsite
- Generous PPE stipend
- High-impact startup environment with significant ownership and autonomy
- Opportunities for rapid career growth and internal advancement
- Direct collaboration with experienced operators, engineers, and industry leaders
- The opportunity to help build and scale transformative energy technology from the ground up
Salary$140,000-$180,000 USD
