Senior/Staff Nuclear Safety Analysis Engineer

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.

Antares Industries is seeking a Senior or Staff Nuclear Safety Analysis Engineer to take ownership of the safety analysis product delivered in support of the final design of the Mark 1 reactor. This individual will lead intact-event (non-breach) safety analysis, drive source term calculations rooted in TRISO fuel behavior and qualification, and translate reactor physics and neutronics uncertainty into radiological dose results. The role requires the judgment to scope phenomenological work appropriately—rigorous enough to defensibly bound figures of merit, without being exhaustive—and the independence to coordinate across every design discipline, the licensing team, and the testing and materials organizations. This is a technical ownership role: the successful candidate will be accountable for the quality, defensibility, and timeliness of safety analysis deliverables that directly support licensing of Mark 1 and inform the technical basis for follow-on designs.

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  Take end-to-end technical ownership of the safety analysis deliverables supporting final design of the Mark 1 reactor scope, technical approach, schedule, and quality.

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  Perform and oversee deterministic safety analysis of intact (non-breach) events. Apply Phenomena Identification and Ranking Table (PIRT) methods and other systematic scoping approaches to focus analysis on dominant phenomena, ensuring figures of merit are adequately and defensibly bounded without exhaustive, low-value modeling.

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  Develop source term calculations that account for TRISO fuel behavior and qualification, including mechanistic failure of fuel layers (e.g., buffer/IPyC/SiC/OPyC) under irradiation and elevated temperature, fission product release and transport, radionuclide grouping, and identification of dominant dose drivers.

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  Understand and quantify how neutronics model uncertainties (power distribution, burnup/depletion, isotopics, cross-section data) propagate through fuel performance and source term models into final dose calculations.

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  Work independently across all design disciplines (core, fuel, mechanical, materials, I&C, plant systems) to define analysis inputs and design-basis requirements, and interface directly with the licensing team to shape license application content, respond to regulator requests for additional information (RAIs), and support licensing evidence documentation development.

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  Identify where test and qualification data (fuel performance, materials, thermal-hydraulic phenomena) is sparse, uncertain, or absent, and partner with the testing and materials teams to define a credible success path for closing those gaps for Mark 1 and beyond.

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  Drive cross-team efforts to verify and validate (V&V) the codes, methods, and tools used in safety analysis, ensuring they are qualified under the applicable nuclear quality program for use in licensing-basis calculations.

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  Author and review quality-affecting technical documentation — calculation packages, methodology reports, safety analysis reports, and topical report content — to a standard suitable for regulatory submittal.

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  Provide technical mentorship to less experienced engineers on safety analysis phenomenology, tools, and methods, and help build organizational depth in these areas.

• B.S. in Nuclear, Mechanical, or a related field (M.S. or Ph.D. preferred)

• 4+ years of relevant reactor safety analysis experience, or an equivalent combination of education and experience.

• Demonstrated hands-on experience with at least one system-level thermal-hydraulic / systems analysis code (e.g., RELAP5-3D, TRACE, SAM, GOTHIC, SAS4A/SASSYS-1, MELCOR, or equivalent), with a track record of learning new phenomenology, tools, and methods quickly.

• Working knowledge of TRISO (or other advanced) fuel performance and qualification, including mechanistic failure modes of fuel coating layers under irradiation and thermal loading.

• Experience developing source terms and radiological dose consequence calculations (e.g., mechanistic or alternative source term methods, radionuclide release and transport, dose driver identification).

• Demonstrated ability in reactor physics / neutronics fundamentals and how model and nuclear data uncertainties propagate into downstream safety and dose calculations.

• Familiarity with PIRT development or comparable phenomena-scoping methods to right-size analysis scope against schedule and risk.

• Demonstrated technical writing skills, with experience producing quality-affecting calculations, methodology reports, or content supporting regulatory submittals.

• Demonstrated ability to work independently, manage competing priorities, and drive alignment and delivery across multidisciplinary engineering teams without close supervision.

• Probabilistic risk assessment (PRA) and its integration with deterministic analysis to define and categorize licensing basis events (LBEs), consistent with risk-informed, performance-based methodologies (e.g., NEI 18-04 / ASME-ANS RA-S).

• Familiarity with the DOE authorization (DOE 1271) and/or NRC licensing framework for advanced reactors (10 CFR Part 50/52 and the emerging Part 53 and 57), relevant regulatory guides (e.g., RG 1.183 alternative source term, RG 1.174 risk-informed decision-making), and the NUREG-0800 Standard Review Plan.

• Experience verifying and validating (V&V) safety analysis codes and methods under a nuclear quality program (e.g., ASME NQA-1), including sensitivity/uncertainty quantification (CSAU, BEPU, or similar frameworks) and formal code qualification for licensing use.

• Experience with radionuclide inventory and dose consequence software (e.g., ORIGEN, MACCS, RASCAL) and atmospheric dispersion modeling.

• Exposure to TRISO or advanced fuel qualification and irradiation testing programs (e.g., AGR-type programs), fuel performance codes (e.g., PARFUME, BISON, AGREE), and statistical fuel qualification methodologies.

• Familiarity with reactor physics / neutronics codes (e.g., MCNP, Serpent, SCALE) and methods for propagating cross-section and depletion uncertainty into safety analysis.

• Experience authoring or defending regulatory submittals — topical reports, safety analysis reports, RAI responses including pre-application engagement with regulators.

• Prior experience at an advanced reactor developer, national laboratory, or major nuclear supplier in a comparable safety analysis, source term, or licensing-support role.

• Experience leading or coordinating technical work across multiple engineering disciplines, subcontractors, or vendor organizations.

To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State. Learn more about the ITAR here.

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, perverse incentives, and emergent and path-dependent properties. First principles thinking alone is insufficient. Think probabilistically and then take action. “If you want to be certain, then you are apt to be obsolete.” Over-optimizing the components often degrades the system

• Obsess over the End User - The customer and end user are often not the same. We will never build globally competitive commercial products if we lose sight of our end users and their entire interaction with the product life cycle

• Be Unconstrained by Convention - Our only limits are the laws of physics. Many, even experts, will say what we are working on is impossible. They said the same about SpaceX reusing rockets. Generationally impactful companies, by definition, must accomplish the seemingly impossible. If it were easy, it would have already been done. Never shy away from a solution because it has never been tried before, and never choose to do something because that's “how it's always been done”

• Go Where the Work Is - Never miss a chance to meet a customer, user, or stakeholder face to face, even if that means hopping on a plane. If you can’t make it, find a teammate who can channel your intentions and go in your place. Deep work can be done from anywhere, but we believe teams are built in person, and aim to maximize our time together

• Operate in the Grey - Embrace nuance in pursuit of truth. Question every fundamental assumption

Antares is an Equal Opportunity Employer. Employment decisions are based solely on merit, competence, and qualifications, without regard to race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability, or any other legally protected status.