Senior Nuclear Engineer

About Us

At Antares, our long-term mission is to make clean energy abundant from Earth to the Asteroid Belt. We’re fueled by the belief that advanced nuclear energy can strengthen our military, solve the climate crisis, elevate global living standards, and expand humanity's presence in outer space. To achieve our mission, we’re building mass‑producible, inherently safe, deployable microreactors that can be used terrestrially, underwater, and in space.

Formed in 2023, the Antares team hails from SpaceX, The White House, MIT, Rigetti Computing, The Air Force, General Atomics, Relativity Space, Ursa Major, and National Laboratories like Los Alamos, Idaho, and Oak Ridge. Antares has raised over $130M in venture capital from top‑tier investors and has over $13M in government funding.

About the Role

As a member of the nuclear engineering team, you will become the responsible engineer for a key component of the Antares reactor design such as reactivity controls and instrumentation, radiation shielding, fuels, materials, thermal hydraulics, safety, or licensing. The ideal candidate has a mix of industry and academic experience, and has worked in a team‑oriented environment to mature nuclear concepts. While you may have a specialty, you’re not afraid to operate as a generalist in a growing organization.

Roles and Responsibilities:

• You will develop and provide expertise in a subset of the following:

• Lead complex neutronics modeling and Multiphysics analysis

• Responsible nuclear engineer for design and integration of components as assigned

• Mentor junior engineers

• Develop and implement modeling and simulation methods and tools

• Coordinate validation and verification activities

• Interface directly with regulatory bodies for licensing and compliance

• Spearhead prototype testing and experimental campaigns

• Lead cross‑disciplinary integration efforts across neutronics, thermal‑hydraulics, structural mechanics, materials, and reactor operations to ensure design margins are maintained across all Figures of Merit (FOMs) and safety‑critical performance metrics

• Identify and define validation, verification, qualification, and testing requirements across engineering disciplines, including opportunities to leverage startup, commissioning, and power ascension testing data for model development and design maturation

Basic Qualifications:

• Master’s or Ph.D. in Nuclear Engineering, Physics, or related field

• Deep experience with and understanding of MCNP, Serpent, or SCALE

• Experience with Multiphysics simulations and methods (thermal‑hydraulics, structural, heat transfer), reactor kinetics, safety analysis, or integrated systems modeling

Preferred

Skills & Experience:

• Advanced programming proficiency (Python, C++, or similar)

• Experience designing or developing high temperature gas reactors, heat pipe cooled reactors, microreactors, TRISO fuel, or other advanced reactors

• Strong leadership and mentorship skills

• Demonstrated success in regulatory processes (DOE, NRC, DoD)

• Previous experience at dynamic tech companies or startups

• Experience with advanced reactor transient and systems analysis tools such as SAM, AGREE, PARCS, or equivalent nuclear systems codes

• Experience with reactor commissioning, startup testing, power ascension testing, and operational readiness activities for nuclear systems

• Deep understanding of reactor shielding design, radiation transport analysis, and variance reduction methodologies, including experience with ADVANTG, MAVRIC, Attila4MC, or equivalent tools

• Experience performing integrated nuclear‑thermal‑mechanical analyses for reactor structures and components, including structural graphite, high‑temperature steels, and other advanced reactor materials

• Demonstrated ability to maintain design margins and performance requirements across coupled neutronic, thermal, mechanical, materials, and operational domains

• Strong systems engineering mindset with the ability to work effectively across disciplinary interfaces and identify data needs for validation, verification, qualification, and licensing activities

• Experience planning and executing experimental programs to generate qualification data, including leveraging commissioning and power…