Mechanical Engineer (Balance of Plant / Plant Systems)

Deploy the next generation of energy infrastructure with Applied Atomics

Applied Atomics delivers firm, clean electricity with proven technology. We design, build, and operate nuclear plants directly alongside the facilities they power. With no reactor science or new fuel to invent, we have no reason to stall. We are the first fully integrated nuclear power provider built to deploy now.

Founded by a team of engineers and operators who built the launch sites, test complexes, and factories behind SpaceX, designed and commercialized nuclear reactors, and ran billion-dollar asset portfolios, the team is now focused on clean power deployment. Applied Atomics is backed by Alpaca VC, Transition, and Morpheus Ventures.

About the role

Applied Atomics is seeking a Mechanical Engineer to support the design, development, and build-out of the major thermal-fluid systems for our first-of-a-kind (FOAK) nuclear power plant. You'll work alongside senior engineers to develop systems such as the main steam system, feedwater system, condensate system, air-cooled condenser (ACC), heat exchangers, pumps, valves, piping, and auxiliary thermal-mechanical equipment.

This is a high-impact role for an engineer who wants to learn fast, contribute to real hardware, and have ownership of major plant systems. You'll perform engineering analysis, system modeling, CAD design, vendor coordination, testing support, and system integration. If you are a strong mechanical engineer who enjoys complex thermal-fluid systems, hands-on hardware, and startup pace, you'll thrive here.

Why we need you

We are transitioning nuclear energy from a theoretical science into a practical reality, and that requires practical problem-solvers. We need engineers who are eager to take direct responsibility for their work and see it through to completion. Your role will be critical in transforming complex designs into safe, reliable, and operational power plants that will operate for decades to come.

Key Responsibilities

• Work on the design and development of balance-of-plant (BOP) systems, including but not limited to: main steam system & piping, feedwater system, condensate system, air-cooled condenser systems, heat exchangers and auxiliary systems, turbine-side thermal cycle equipment & interfaces.
• Support creation of mechanical design concepts, equipment layouts, and piping configurations.
• Ensure designs comply with applicable design criteria, requirements, and system interfaces.
• Perform thermal, structural, and fluid analyses using hand calcs and engineering tools.
• Support development, review, and validation of system simulation and analytical models (e.g., thermal cycles, pressure drops, transient behavior, etc.).
• Create and update CAD models, drawings, and system diagrams (NX, SolidWorks, Creo, etc.).
• Proficient with fluid system PIDs.
• Develop and maintain design documentation, including descriptions, technical notes, calculations, and engineering change packages.
• Support preparation and presentation of PDRs, CDRs, and internal design gates.
• Support vendor outreach for pumps, valves, heat exchangers, piping, instrumentation, and packaged equipment.
• Support manufacturing, assembly, and installation of BOP systems.
• Support development of test plans, integration procedures, and commissioning documentation.
• Participate in hardware bring-up, field testing, and system-level troubleshooting as needed
• Interpret and implement industry codes and standards (ASME, API, NRC, etc.).
• Collaborate with interfacing system owners.
• Support documentation for regulatory submissions (e.g., NRC).
• Define and manage Bills of Materials (BOMs), component specifications, and configuration control.
• Develop system schedules, budgets, and resource plans.

Additional Responsibilities

• Take end-to-end responsibility for your projects, from initial concepts through to deployment and ongoing operations
• Partner closely with our multidisciplinary team of experienced engineers to tackle complex, cross-functional challenges
• Deliver high-quality work steadily and safely, ensuring every solution meets our rigorous quality standards while also for solving scalability issues in the future
• Continually improve our internal engineering processes, documentation, and tools to support the team as we scale

What you bring to the table

Need to haves

• Bachelor's degree in Mechanical Engineering or related field.
• 2-4 years of mechanical or fluid system design experience (1-2 years w/ MS).
• Strong understanding of mechanical fundamentals: thermodynamics, heat transfer, fluid mechanics, material behavior, and structural mechanics.
• Experience with CAD tools (NX, SolidWorks, Creo, etc.).
• Experience with fluid system PID.
• Ability to perform engineering analysis using hand calcs and/or software.
• Exposure to industrial fluid systems, piping, pumps/compressors, heat exchangers, and/or turbomachinery).
• Familiarity with applicable mechanical/industrial codes and standards (ASME, API, NRC, NFPA, etc.).
• Strong technical communication and documentation skills.
• Self-starter and ownership mentality.
• Eagerness to learn, ask questions, and contribute to a fast-moving, multidisciplinary team.

Nice-to-haves

• Master's degree in Mechanical Engineering or related field.
• 4+ years of experience in mechanical, industrial, aerospace, energy, oil & gas, thermal, or plant engineering roles.
• Experience with mechanical/industrial codes and applying to system designs (ASME, API, NRC, etc.).
• Experience with FEA (ANSYS, Abaqus, FEMAP, etc.).
• Hands-on experience with hardware builds, field work, testing, and/or commissioning.
• Experience supporting design of piping, pressure vessels, heat exchangers, or steam systems.

Benefits & Perks for Eligible Employees

• Substantial incentive stock plan for all full-time employees.
• Medical / Vision / Dental (details forthcoming).
• Flexible PTO policy.
• Hybrid and remote work options depending on role.
• Other benefits to be announced at offer stage.

• We are unable to provide visa sponsorship at this time.
• This position involves access to technology that is subject to U.S. export controls.
• Any job offer made will be contingent upon the applicant's capacity to serve in compliance with U.S. export controls.

Remote pay range $138,342—$195,322 USD