Senior Nuclear Methods Engineer

About this role

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.

The Antares team hails from SpaceX, the White House, the Pentagon, the Department of Energy, MIT, Rigetti Computing, General Atomics, Relativity Space, Ursa Major, and National Laboratories like Idaho, Oak Ridge, Los Alamos, and Savannah River. Antares has raised over $600M in venture capital from top-tier investors and has hundreds of million-dollars on contract with the military services, NASA, and the Department of Energy.

About the Role

As a Senior Nuclear Methods Engineer you are responsible for developing, qualifying, and continuously improving the nuclear analysis methods that underpin reactor design, safety, and licensing. The position owns the technical foundation for steady-state and transient analyses, ensures engineering rigor through validation and uncertainty management, and translates nuclear methods into actionable design inputs for hardware development, manufacturing, and reactor operation. A key aspect of the role is continuously improving design confidence and recovering margin by incorporating lessons learned from testing and operational data throughout the reactor lifecycle.

Key Responsibilities

- Develop and maintain steady-state and transient nuclear analysis methods used for reactor design, safety analysis, and licensing.

- Qualify analysis methods through code-to-code comparisons, benchmark problems, experimental validation, and uncertainty quantification.

- Establish, document, and maintain biases, uncertainties, conservatisms, and design margins across all nuclear analysis methods.

- Perform gap analyses to identify deficiencies in methods, validation data, tools, and technical capabilities, and develop plans to close those gaps.

- Ensure nuclear analysis products are directly mapped to the needs of the safety case, licensing basis, mechanical design, manufacturing, and hardware delivery.

- Develop sensitivity and uncertainty capabilities to quantify the impact of design changes, manufacturing tolerances, and operational variability on reactor performance and safety margins.

- Define best practices and analysis workflows that maintain traceability, consistency, and engineering rigor throughout the design lifecycle.

- Work closely with design, safety, licensing, materials, manufacturing, and testing teams to ensure analysis methods support program milestones and engineering decisions.

- Leverage data from component testing, integrated system testing, and reactor operation to continuously improve methods, reduce uncertainty, and recover design margin for future block upgrades.

Basic Qualifications

- Bachelor’s degree in Nuclear Engineering, Mechanical Engineering, Physics, or a related technical discipline.

- 4+ years of professional experience in nuclear engineering, reactor physics, nuclear methods development, safety analysis, or a related field.

- Experience with reactor physics and transport tools such as MCNP, Serpent, SCALE, OpenMC, MOOSE-based applications, or similar codes.

- Experience with transient reactor analysis and coupled neutronics/thermal-hydraulics methods.

- Experience performing steady-state and/or transient analysis of nuclear reactor systems.

- Working knowledge of reactor physics, neutronics, thermal-hydraulics, or coupled Multiphysics analysis.

- Experience using nuclear analysis or simulation tools to support reactor design, safety analysis, or engineering decisions.

- Understanding of verification and validation (V&V), benchmarking, sensitivity analysis, and/or uncertainty quantification.

- Ability to translate analytical results into engineering requirements, design inputs, margins, and technical recommendations.

- Strong technical documentation skills with the ability to clearly communicate assumptions, methodologies, uncertainties, and results to multidisciplinary engineering teams.

Preferred Skills & Experience

- Master’s or Ph.D. in Nuclear Engineering, Reactor Physics, Applied Physics, or a related technical discipline.

- Experience developing, qualifying, or maintaining nuclear analysis methods rather than solely applying established tools.

- Demonstrated experience with code-to-code comparisons, benchmark evaluations, experimental validation, sensitivity analysis, and uncertainty quantification.

- Experience establishing and managing analytical biases, uncertainties, conservatisms, and design margins.

- Familiarity with nuclear regulatory and licensing frameworks and the development of analysis methods used to support a safety case or licensing basis.

- Experience developing automated analysis workflows, data pipelines, or engineering tools using Python, C++, MATLAB, or similar programming languages.

- Experience incorporating test or operational data into model calibration, validation, uncertainty reduction, or design-margin recovery.

- Experience supporting advanced reactor development, including microreactors, high-temperature gas reactors, fast reactors, molten salt reactors, or other non-light-water reactor technologies.

- Familiarity with software quality assurance, configuration management, and traceability requirements for safety-related or licensing analysis tools.

Culture

At Antares, we like to specifically tie each role to our founding document’s set of values–here are the top five cultural values we think you should believe at your core to be successful:

- Think in Systems - Energy and Defense are complex ecosystems with numerous stakeholders with competing priorities, conflicting policies, perv

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