Nuclear Engineer (Lead)

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 n o reactor science or new fuel to invent , we have n o 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 b acked by Alpaca VC, Transition, and Morpheus Ventures. About the role: Applied Atomics is seeking a Nuclear Engineer to own and drive the technical development of our reactor core, fuel, and associated nuclear systems. As one of our first nuclear engineering hires, you will define the nuclear architecture of our system, lead early-stage reactor and fuel design efforts, and act as the primary technical interface with our reactor-licensing partners. Your work will span reactor physics, core design, neutronics modeling, shielding, nuclear safety, fuel performance, and design adaptation of licensed reactor technology. This role is ideal for someone who wants broad responsibility, thrives in a fast-paced hardware environment, and is excited to build and eventually lead a world-class nuclear engineering team. 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. What you will do Nuclear Design & Analysis Own reactor physics, neutronics, shielding, and nuclear design activities from concept through deployment. Develop and refine core design, reactivity coefficients, kinetics parameters, feedback mechanisms, and neutron energy spectra. Perform radiation transport, shielding, and criticality safety analyses. Conduct transient and accident-scenario evaluations to support design decisions and safety basis development. Perform dose consequence and source-term calculations (normal operations + beyond design basis events). Modeling & Simulation Build and maintain reactor physics, shielding, and fuel performance models. Computer energy deposition distributions, power profiles, isotopic depletion, and fuel cycle analyses. Verify model assumptions and assess margin/conservatism across analyses. Lead Verification & Validation (V&V) efforts for nuclear analysis tools and workflows. Fuel, Materials, & Reactor Integration Support fuel form selection, cladding and structural material evaluation, and fuel performance modeling. Contribute to reactor mechanical layout, shielding design, and core structural features. Work with thermal-hydraulic engineers to ensure robust coupling between neutronics and thermal-fluid analyses. Partner & Licensing Interface Collaborate with licensed reactor technology providers to adapt designs for Applied Atomics’ requirements, constraints, and integration needs. Work with regulatory and licensing teams on technical inputs to safety basis, design certification, and licensing documentation. Technical Leadership Server as the nuclear technical authority within a multidisciplinary, fast-paced engineering organization. Build out processes, methods, and eventually a team for nuclear analysis and reactor design. 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 Nuclear Engineering or related field. 4+ years of nuclear engineering experience ( or 2+ years w/ MS). Demonstrated experience with radiation transport and reactor physics modeling tools (OpenMC, MCNP, Serpent, SCALE, etc.). Experience with reactor design, core physics, criticality, and/or shielding. Basic understanding of thermal-hydraulics and coupled neutronics-thermal models. Familiarity with CAD tools (NX, SolidWorks, Creo, etc.). Ability to operate across multiple cross-functional teams. Strong written and oral communication skills; able to explain complex topics simply. Self-starter, ownership mentality, and ability to drive tasks from concept to completion. Nice-to-haves: Master’s degree in Nuclear Engineering or related field. Experience with advanced analysis tools such as: OpenMC, Serpent, MCNP, SCALE, Attila4MC RELAP, Trace, MOOSE, Pronghorn, GRIFFIN, etc. Experience with dose consequence tools such as MAACS or NRC RADTRAN. Hands-on hardware, prototyping, or test experience (core mockups, shielding tests, irradiation programs, etc.). Experience with fuel performance analysis (FRAPCON, BISON, FAST, etc.). Understanding of nuclear materials, irradiation effects, corrosion, and structural degradation. Experience with finite element simulation (ANSYS, Abaqus, etc.). Knowledge of relevant regulatory standards (ASME, NRC regs., 10 CFR 50, etc.). Prior experience with FOAK (first-of-a-kind) or advanced reactor development programs. 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 an equal opportunity employer, and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law. 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 $147,500 — $195,322 USD