Senior Mechanical Engineer - Fluid Systems

About Pacific Fusion

Pacific Fusion was founded in 2023 with the mission to power the world with abundant, affordable, clean energy.

We are rapidly designing and building a pulser-driven inertial fusion system to achieve net facility gain (more fusion energy output than stored energy input). In parallel, we are developing the key components required to build affordable fusion systems.

Our plans are ambitious. We have raised over $900M so far from incredible investors, resourcing us to deliver on these plans. We are bringing together the best scientists, engineers, and operators from the fusion community, hard tech industry, and other sectors. We are united by a shared sense of urgency to provide clean power for the world, particularly managing climate change while meeting growing global energy demand. You can read more about us in this letter from our founders.

Why This Role Matters

Pacific Fusion is seeking an exceptional Senior Mechanical Engineer – Fluid Systems to help create the path to commercial fusion energy. You will take ownership of fluid system development and deployment in support of our demonstration system, solving multidisciplinary engineering problems necessary for proving net-facility gain using pulsed magnetic inertial fusion. This role reports to the Senior Process Engineer in Pulser Engineering and sits at the intersection of fluid systems design, thermal management, and hands-on hardware integration. You will work onsite at our Fremont, CA office, with periodic collaboration at our San Leandro, CA Build Center.

What you'll do

• Take full ownership of fluid system designs — including thermal and structural subsystem considerations — continuously refining design specifications to meet evolving system requirements.
• Develop novel hardware solutions by leveraging historical engineering knowledge and first-principles thinking, and validate these solutions through rigorous testing.
• Design fluid system hardware and process engineering tools (ePLAN), conducting detailed analysis with specialized in-house and external tools
• Lead designs from concept through fabrication and test, building and testing assemblies in our Fremont Research High Bay and San Leandro Build Center.
• Coordinate with multidisciplinary teams — including electrical, software, manufacturing, and pulser engineering — to deliver integrated system-level designs.
• Work closely with experienced technicians to implement and integrate hardware designs hands-on.
• Conduct and participate in design reviews, utilizing feedback to achieve fully functional, production-ready systems.
• Address and resolve hardware development issues that arise on integrated fluid system components.
• Oversee the creation of detailed design documentation, drawings, and specifications for fluid systems.

What you bring

• Bachelor's degree in Mechanical Engineering or a related engineering discipline; Master's or PhD is a plus.
• 7+ years of professional experience delivering on full-scope engineering projects, including schedule ownership.
• Experience applying engineering first-principles and method-based thinking to challenging problems.
• Hands-on exposure across multiple engineering disciplines, including fluids, mechanical, structural, and thermal.
• Proficiency in CAD software (Creo Parametric preferred) and strong 3D modeling habits.
• Experience with analytical tools such as MATLAB, Simulink Simscape, ANSYS Fluent, or equivalent.
• Proven track record of taking mechanical designs from concept through fabrication and test.
• Hands-on experience in laboratory or prototype environments — comfortable with rapid iteration and ambiguity.
• Excellent written and verbal communication skills, including the ability to communicate trade-offs clearly across disciplines.

Bonus Points

• Experience in fusion, plasma physics, accelerator physics, defense, or other high-consequence technical environments.
• Familiarity with process engineering tools such as ePLAN.
• Exposure to large-scale thermal management systems, coolant loops, or industrial fluid handling.
• Experience with vacuum systems, cryogenics, high-voltage hardware, or pulsed power components.

Total Compensation & Benefits for Eligible Employees

• Industry-competitive salary

• Equity plan

• 6% employer 401k matching

• Generous paid time off (including sick leave, vacation, paid family leave)

• Medical, Dental, and Vision insurance

Actual base salary offered will be determined by: experience, skills, and work location. This range is for base salary, our total compensation includes equity and benefits. We welcome you to apply even if your expectations are outside our listed range.

Pacific Fusion is committed to creating a diverse environment and is proud to be an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status.

Pacific Fusion is committed to providing reasonable accommodations for qualified individuals with disabilities in our job application procedures and throughout employment. If you need assistance or any accommodation, please let us know.

Pacific Fusion does not accept unsolicited resumes from recruiters or employment agencies without a fully executed recruitment agreement in place. In the absence of such agreement, Pacific Fusion reserves the right to pursue and hire any candidates without an obligation to pay fees. Agencies are requested not to contact Pacific Fusion hiring managers or employees regarding recruiting services.