About Commonwealth Fusion Systems:

Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy.

Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And we're working with policymakers, suppliers, and many others to build the energy industry of the future.

We’re in the best position to make it happen. Since 2018, we’ve raised $4 billion of capital, making us the largest and leading fusion company in the world.

Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.

If that’s you and this role fits, we want to hear from you. Join the power movement as a Staff Process Engineer

CFS is looking for a Staff Process Engineer with deep chemical engineering fundamentals and extensive experience scaling up, commissioning, and operating systems in large industrial facilities (e.g., power generation, LNG, petrochemicals, or cryogenics). You excel at navigating loosely-defined outcomes, translating fundamental requirements into practical industrial systems, and guiding complex designs from early concepts through Front-End Loading (FEL), detailed engineering, construction, and operation.

Fusion power plants bring together technologies that traditionally span multiple industries. At CFS, you will work across cryogenics (nitrogen and helium), power generation (steam), molten salts (FLiBe), fueling (deuterium-tritium), gas processing, vacuum systems, and utilities. Acting as a domain expert, you will apply real world, hands-on experience to build process design bases from scratch for ambiguous projects, develop heat and material balances, size equipment, own P&IDs, lead HAZOPs, support start-up, and troubleshoot operating systems.

What you'll do:

• Own the process engineering scope for complex systems with loosely-defined outcomes, guiding them from early concept through operation with near complete independence
• Translate fundamental engineering requirements into commercially viable systems, navigating semi-ambiguous challenges to develop process design bases, operating envelopes, PFDs, heat/material and utility balances, P&IDs, and process datasheets
• Apply chemical engineering fundamentals (thermodynamics, phase equilibrium, fluid mechanics, heat and mass transfer, transport phenomena, reaction engineering, separations, and process control) to resolve complex technical challenges and define operating boundaries
• Develop steady-state and dynamic process models using engineering analysis to guide process design, system architecture, and equipment selection
• Size, specify, and evaluate process equipment, working directly with suppliers, fabricators, and internal multidisciplinary teams to evaluate technical tradeoffs (performance, safety, cost)
• Drive engineering through a phase-gated design process, progressively maturing systems from conceptual to engineering definition
• Lead process safety activities, including HAZOPs, design reviews, and relief/depressurization studies, and develop control philosophies and interlocks in collaboration with controls engineers
• Support field execution by generating detailed work and commissioning plans, test procedures, and start-up strategies, actively participating in system commissioning and performance testing
• Troubleshoot operating equipment using first-principles engineering and field data, translating lessons learned into process improvements, new tools, and department policies
• Provide technical leadership, manage medium-to-large project risks by driving solutions, and mentor less-experienced engineers on complex process engineering problems

What we're looking for:

• Bachelor’s degree in Chemical Engineering (or closely related discipline)
• 10+ years of relevant industrial process engineering experience (potentially fewer if a PhD), or equivalent demonstrated depth of experience
• Demonstrated deep domain expertise (or broad expertise across domains) with a proven ability to independently own complex, semi-ambiguous work, seeking support only when needed
• Strong command of chemical engineering fundamentals and a proven track record taking systems through a structured FEL or phase-gated development process
• Experience scaling up loosely-defined process requirements into commercial-scale equipment and facilities
• Deep expertise developing core process engineering deliverables (design bases, PFDs, P&IDs, heat/material balances) and sizing/selecting industrial process equipment
• Hands-on experience commissioning, operating, and troubleshooting physical equipment alongside operators, using field observations to diagnose performance
• Proficiency with process simulation tools (e.g., EcoSim, Aspen HYSYS/Plus, AVEVA) and extensive experience applying industry codes and standards (such as ASME B31.3, ASME BPVC Section VIII, API 520/521) to establish process design boundaries, fluid service classifications, operating envelopes, and relief/depressurization cases
• Strong background in process safety, hazard identification and risk analysis (e.g., HAZOP), and relief system design
• Experience integrating cross-functional engineering disciplines and working directly with vendors, EPC organizations, or construction contractors
• Ability to independently manage medium risks, drive solutions for larger project risks, and exercise strong engineering judgment to ensure practical, commercially viable designs
• Values that align with our company’s values of integrity, execution, impact, and self-critique

Bonus points for:

• Experience with large-scale cryogenic systems (particularly supercritical or liquid helium) and industrial high-vacuum systems
• Background in large-scale process facilities (power generation, petrochemical, LNG, industrial gases, nuclear)
• Expertise in steam systems, molten salt systems, or industrial gas processing (purification, separation, fueling)
• Experience with large-scale utilities (cooling water, chilled water, compressed/instrument air, nitrogen)
• Track record of scaling first-of-a-kind technologies from pilot/demonstration scale to commercial operation
• Experience with dynamic process simulation and consequence analysis
• Licensed as a Professional Engineer

Must-have requirements:

• Ability to lift up to 50 lbs occasionally
• Perform activities such as stooping, climbing, typing, standing, and sitting for extended periods of time
• Willingness to occasionally travel or work required nights/weekends/on-call, including occasional travel to suppliers, contractors, or operating facilities
• Willingness and ability to work hands-on in industrial, construction, commissioning, and operating environments
• Dedication to safety to mitigate hazards that may include heat, cold, noise, fumes, strong magnets, lead, high voltage, high current, pressure systems, vacuum systems, hazardous materials, and cryogenics

Salary range for this full-time position + equity + benefits. The actual salary will depend on level, location, qualifications, and experience. The range displayed on each job posting reflects new hire salaries for the position across all US locations. Benefits include:

• Competitive compensation with equity
• 13 Company-wide Holidays
• Flexible vacation days
• 10 sick days
• Generous parental leave policy
• Health, dental, and vision insurance
• 401(k) with employer matching
• Professional growth opportunities
• Team-building activities

LI-Onsite

At CFS, we excel in fast-paced environments, driven by our values of integrity, execution, impact, and self-critique. As we grow, we’re eager to bring on mission-driven folks who offer diverse perspectives and fresh ways to tackle challenges.

We value diversity deeply and are proud to be an equal opportunity employer by choice. We consider all qualified applicants equally, regardless of race, color, national origin, ancestry, citizenship status, protected veteran status, religion, physical or mental disability, marital status, sex, sexual orientation, gender identity or expression, age, or any other basis protected by law.

This role requires compliance with U.S. laws concerning the export of controlled or protected technologies or information (collectively, “Export Control Laws"). Any offer of employment will be contingent on the need for compliance with such Export Control Laws.