Senior Thermo-Mechanical Engineer

About the company

Antares is a nuclear power startup developing small modular reactors (SMRs) using TRISO fuel for deployment at U.S. military bases.

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 the Thermal-Mechanical Engineer for Integration of the Power Conversion System (PCS), you will own how heat moves through the Power Conversion System, including the thermal budget and its impact on hardware over time. Your scope runs from the thermal energy budget of the whole system down to the insulation on a single hot-section joint. You will develop the heat rejection and cold-sink architecture that closes the cycle, size and integrate the recuperator, define the thermal configuration of the hot section (insulation, heat-loss budget, surface temperatures, and personnel protection), and hold the thermal interfaces and transient requirements against the major PCS components, the reactor, and the safety systems. You are responsible for managing temperature-related life-limited hardware including mitigations, inspection procedures and processes, and a maintenance plan that manages that risk. You will participate in testing and data reviews for test rigs, full-scale hardware, and deployed reactors. You will drive instrumentation placement, correlate your models against what the PCS actually does, and take the delta back into the design. The ideal candidate is fluent in heat transfer across conduction, convection, and radiation, has sized real thermal hardware rather than only analyzed it, and is comfortable owning the heat-loss budget and the cold-sink margin and working with component owners to ensure thermal performance is met. Experience with high-temperature power cycles, creep and thermal-mechanical fatigue life, or bringing first-of-a-kind hardware through thermal commissioning is a strong differentiator. Key Responsibilities: - Own thermal management and thermal energy budget of the Power Conversion System and close the loop with cycle performance on parasitic losses. - Develop the heat rejection and cold-sink architecture, sizing and integrating the recuperator and heat rejection against site and ambient conditions. - Define the thermal configuration including insulation selection and design, heat-loss budget, surface temperatures, instrumentation, and personnel protection. - Manage thermal interfaces and thermal transient requirements for major PCS components, reactor, and safety systems. - Support test rig design and instrumentation placement. Utilize collected data to improve component life and performance. - Engineer components for high-temperature and high-stress service using metals and advanced materials, in partnership with materials and structural analysis. - Work with the team to develop inspection and maintenance plans that manage risk on thermal-mechanically life-limited. - Work with Mechanical, Electrical, Safety, and Nuclear teams to ensure the designs meet the overall objectives and requirements. Basic Qualifications: - Bachelor's degree in Mechanical, Aerospace, Nuclear, or a related engineering discipline - or 5+ years for Senior Engineer, including hands-on analysis, hardware design, build, and test - Experience performing thermal analysis (hand calculations and FEA or CFD) to size, configure, or qualify hardware - Experience designing thermal management hardware for high-temperature systems, such as insulation systems, heat-loss budgets, or thermal isolation - Experience sizing or integrating heat exchangers or a heat rejection path against real operating and ambient conditions - Experience correlating thermal predictions against test data and revising a design based on the result - Experience owning thermal interfaces or requirements across multiple subsystems Preferred Skills & Experience: - Experience in the Nuclear, Aerospace, Automotive, Power Generation, Motorsports, or Oil and Gas industries - Experience with recuperators, air-cooled or dry heat rejection, and ambient-dependent performance derating - Experience selecting and designing high-temperature insulation systems, including hot-face and cold-face design and personnel-protection surface temperature limits - Experience with transient thermal analysis of startup, shutdown, trip, and off-nominal cases - Experience with thermal-mechanical fatigue, creep, and creep-fatigue interaction, and with life assessment of temperature-limited components - Experience with elevated-temperature design codes such as ASME BPVC Section III Division 5 or Section VIII Division 2 Part 5 - Experience with high-temperature metals and advanced materials, including nickel superalloys and their creep-limited allowable - Experience specifying thermal instrumentation (thermocouple and RTD selection, placement, and measurement uncertainty) and using it to correlate models - Experience developing inspection and maintenance plans for life-limited hardware, including NDE method selection - Experience with thermal and structural analysis tools such as ANSYS Mechanical, Femap or NX Thermal, and/or CFD tools such as Fluent or Star-CCM+ - Experience commissioning first-of-a-kind hardware and supporting thermal startup and troubleshooting - Experience in a demanding, fast-paced developm