Senior Thermal Mechanical Engineer, Piping Systems

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 Mechanical Engineer at Antares, you will own the design, analysis, and integration of high-temperature, high-pressure piping systems within our Power Conversion System (PCS). Your scope includes the piping connecting turbomachinery, heat exchangers, and other major components of our closed Brayton cycle, ensuring structural integrity, thermal compatibility, and reliable operation across all operating conditions.

The ideal candidate has extensive experience in piping design and stress analysis, understands the challenges of thermal expansion, vibration, and pressure loading, and is comfortable taking designs from initial layout through detailed engineering, manufacturing, and testing.

Key Responsibilities

• Own the design, layout, and mechanical integration of PCS piping systems, including piping specifications, supports, expansion joints, and component interfaces.

• Perform piping stress and structural analyses under sustained, thermal expansion, transient, vibration, and fatigue loading conditions.

• Evaluate piping loads on connected equipment, including turbomachinery, heat exchangers, pressure vessels, and supporting structures.

• Develop detailed piping designs, engineering calculations, specifications, drawings, and documentation in accordance with applicable ASME codes and standards.

• Work closely with thermal, mechanical, structural, and systems engineers to optimize piping configuration, pressure losses, manufacturability, and overall system integration.

• Support hardware procurement, fabrication, assembly, testing, and troubleshooting, including working directly with suppliers and technicians.

Basic Qualifications

• Bachelor's degree in Mechanical Engineering or a related engineering discipline.

• 5+ years of relevant experience for Senior level; 8+ years for Staff level.

• Experience designing high-temperature and/or high-pressure piping systems for industrial or power generation applications.

• Proficiency in piping stress analysis, including thermal expansion, support reactions, and equipment nozzle loads.

• Familiarity with piping design codes such as ASME B31.3 or B31.1.

• Experience developing and reviewing piping layouts, P&IDs, engineering drawings, and fabrication documentation.

Preferred Skills & Experience

• Experience in Nuclear, Power Generation, Oil & Gas, Aerospace, or other high-performance thermal-fluid systems.

• Proficiency with piping stress analysis tools such as CAESAR II, AutoPIPE, or equivalent, and familiarity with FEA tools.

• Experience with piping vibration, pulsation, acoustic loading, water hammer, and fatigue assessment.

• Experience designing pipe supports, flexible connections, expansion joints, and high-temperature piping interfaces.

• Familiarity with ASME BPVC requirements, including Section III, and applicable nuclear quality standards.

• Hands-on experience supporting fabrication, installation, commissioning, and troubleshooting of complex piping systems.

• Experience working in a fast-paced hardware development environment.

Location:

• We are located in Torrance, CA in a 322,000-square-foot, brand-new facility featuring large open spaces for team collaboration, R&D, and production, as well as easy access

Salary Range:

• Senior Thermo-Mechanical Engineer - $150,000 - $190,000

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, 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

Equal Opportunity

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.

ITAR Requirements

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.