Senior Mechanical Engineer, Piping Systems

About the company

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.

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.

Requirements

• 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 qualifications

• 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

Torrance, CA — 322,000-square-foot facility with open collaboration spaces, R&D, and production.

Pay

Senior Thermo-Mechanical Engineer: $150,000 – $190,000 per year.

Culture

Antares ties each role to its founding values. The top five cultural values for this role:

• 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