NextGenEnergyJobsModern Power System Jobs

Senior Process Engineer, Numenor (Reactor)

Valar Atomics

Torrance, CA

Full Time

Posted November 9, 2026

$140k - $180k

Nuclear Energy

Apply Now

Application opens on company website

Listing evidence and provenance

Source: Greenhouse View original listing
Freshness: Open in the current public read path; this is not an employer guarantee.Last observed November 10, 2026
Classification: Modern power-system classification not yet published for this listing.Legacy source industry field: Nuclear Energy
Pay provenance: Employer-provided pay

Job Description

The Numenor team is building Valar’s next reactor, the flagship program that will define how we deliver nuclear power at scale.

Key Responsibilities

Valar 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.
Process 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.

Requirements

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.
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.

Benefits & Perks

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