Director of Mechanical Engineering, Numenor (Reactor)

Valar Atomics • Torrance, CA

7h • $240,000 - $325,000

About The Position

Valar Atomics seeks a Director, Mechanical for its Numenor reactor program. This role will build and lead the program’s mechanical engineering organization, including engineering managers and responsible engineers. The scope includes mechanically dominated systems such as the reactor, control rods, helium pressure boundary and services, HVAC, and Citadel. The Director will lead mechanical engineering from the first unit through scaled production, with the goal of delivering reactors at an increasing rate. The role requires hands-on technical authority and a hardware-first approach while maintaining the integrity, rigor, and control needed to ensure the design basis is met.

The Numenor team is developing Valar’s flagship reactor program and owns the plant, including the reactor core, helium systems, cooling, plant modules, and Citadel. The work spans bringing the first unit to life and establishing a production line that can deliver reactors faster with each build.

The Director will own the mechanical design basis, make final technical decisions on design acceptability, margins, materials, and code selection, and lead design reviews and gate decisions through design freeze. The role will take designs through procurement specifications, factory build, assembly, integrated testing, and commissioning, while establishing verification strategy and designing for manufacture and repeatability. The Director will also lead and mentor the mechanical organization, manage its scope, schedule, and budget, guide staffing as the program scales, and coordinate with systems engineering, safety, IC&E, quality, and supply chain.

The position offers a competitive base salary of $240,000–$325,000 USD, equity ownership, comprehensive medical benefits, unlimited PTO, onsite meals, a PPE stipend, and opportunities for career growth and advancement. Applicants must be legally authorized to work in the United States as a U.S. citizen or lawful permanent resident.

Requirements

• 10+ years of mechanical engineering experience on complex hardware, such as pressure systems, heat-transfer equipment, mechanisms, or large structures.
• Hands-on experience serving as the technical authority who signs off designs, sets margins, and owns design decisions.
• Experience leading mechanical scope for first-of-a-kind hardware from concept through build, test, and commissioning.
• Strong foundation in stress analysis, thermal design, materials, and pressure-vessel and piping codes.
• Experience managing mechanical engineering teams, including managers, and key vendor relationships across multiple project phases.
• Applicants must be legally authorized to work in the United States as a U.S. citizen or lawful permanent resident.

Nice To Haves

• Experience with high-temperature, high-pressure systems such as pressure vessels, heat exchangers, and piping.
• Experience taking first-of-a-kind hardware from design through build and test in aerospace, power generation, oil and gas, or defense.
• Experience with helium or other gas systems, including sealing, leak tightness, and rotating equipment.
• Experience with precision mechanisms and actuators and their qualification testing.
• Working knowledge of ASME pressure-vessel and piping codes, including Section VIII and B31.3.
• Experience with design for manufacture and scaling from prototype to series production.
• Nuclear industry experience in commercial, defense, or national laboratory settings; described as a plus, not a prerequisite.
• Mechanical PE license; described as a plus.

Responsibilities

• Own the mechanical design basis for the reactor, primary helium loop, cavity cooling, helium services, plant modules, and related systems.
• Make final technical decisions on design acceptability, margins, materials, and code selection.
• Run design reviews and make gate decisions from concept through design freeze.
• Take designs through procurement specifications, factory build, assembly, and integrated testing.
• Set the test and verification strategy with the V&V lead and support commissioning through first operation.
• Design for manufacture and repeatability so each unit can be built faster than the last.
• Build, lead, and mentor the mechanical engineering organization, including engineering managers and system responsible engineers.
• Manage mechanical scope, schedule, and budget within the reactor program.
• Lead mechanical team structure and staffing as the program scales.
• Coordinate with systems engineering, safety, IC&E, quality, and supply chain to maintain an integrated plant design.

Benefits

• Competitive base salary
• Equity ownership
• 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

What This Job Offers

• Job Type: Full-time
• Career Level: Director
• Education Level: No Education Listed