Commonwealth Fusion Systems

Senior Manager, Mechanical Engineering - Vacuum Vessel

Join Commonwealth Fusion Systems in Devens, Massachusetts as Senior Manager, Mechanical Engineering. Lead the design and delivery of the ARC vacuum vessel, a key fusion power plant component. Enjoy competitive salary, equity, flexible vacation, and health benefits while driving fusion energy innovation.
Commonwealth Fusion Systems
Commonwealth Fusion Systems
Devens, Massachusetts, United States On-site Full time US$150,000–225,000 annually UTC-05:00

Commonwealth Fusion Systems

Company Overview

Name

Commonwealth Fusion Systems (CFS)

Headquarters

Cambridge, MA, United States

Founded

2018

Size

Approximately 430 employees (source: zoominfo.com). Revenue figures vary, with reports indicating $211.3 million or $31.7 million, though as a pre-revenue fusion developer focused on R&D, these may reflect funding or operations rather than sales.

What They Do

Commonwealth Fusion Systems (CFS) is a pioneering private fusion energy company that specializes in tokamak-based magnetic confinement fusion. Founded as a spinout from MIT's Plasma Science and Fusion Center, CFS focuses on utilizing high-temperature superconducting magnets to achieve commercial net energy production (source: cfs.energy). The company has made significant strides in its technology, particularly with the development of compact fusion machines that leverage decades of tokamak science. Their flagship projects, SPARC and ARC, aim to demonstrate net energy gain and commercial viability in the coming years (source: cfs.energy).

Projects & Track Record

CFS is currently engaged in several groundbreaking projects, most notably the construction of SPARC, which is set to be the world's first net-energy fusion machine. Located at their Fusion Energy Campus in Devens, Massachusetts, SPARC aims to demonstrate net energy gain by the late 2020s (source: cfs.energy). Additionally, CFS is planning the ARC project, a 400 MW-class grid-scale tokamak power plant designed for commercial deployment in the early 2030s. These projects are underpinned by significant technological advancements, including the successful testing of the central solenoid magnet module (CSMC) in November 2024, which confirmed the manufacturability of critical components for SPARC (source: zoominfo.com).

Recent Developments

In the past two years, CFS has made remarkable progress, including the opening of its Devens Fusion Energy Campus on February 10, 2023, which was attended by notable figures such as U.S. Secretary of Energy Jennifer Granholm (source: cfs.energy). The company has also secured substantial funding, raising $863 million in August 2024, building on a previous $1.8 billion round in May 2023, bringing total funding to over $2 billion (source: wbjournal.com). Furthermore, CFS announced its first commercial power plant site in Chesterfield County, Virginia, which will be independently financed and operated, with plans for grid connection in the early 2030s (source: zoominfo.com).

Working There

CFS offers a range of roles across various disciplines, including fusion science, engineering, manufacturing, and materials science. The majority of their workforce is based at the Devens campus, which has grown to over 430 employees (source: cfs.energy). The company culture emphasizes rapid execution and transparency, attracting top talent from the fusion and manufacturing sectors. Key executives include Co-Founder and CEO Bob Mumgaard, along with other leaders in operations and science, indicating a strong demand for expertise in tough tech and physics (source: nasdaqprivatemarket.com). While specific benefits are not detailed, the scale-up and investor backing suggest competitive packages for high-caliber roles in a mission-driven environment (source: cfs.energy). Job seekers are encouraged to monitor their careers page for openings related to SPARC and ARC advancements.


Last updated on Feb 23, 2026 | Report an issue

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 Senior Manager, Mechanical Engineering

CFS is looking for a creative, experienced mechanical engineering manager to lead the design and delivery of the ARC vacuum vessel. Commonwealth Fusion Systems is currently designing the ARC fusion power plant. Within the ARC plant, the ARC tokamak consists of many large mechanical structures that support the large loads and extreme conditions of the fusion plasma. One of the newest and most interconnected components in ARC will be the vacuum vessel, a hundred-ton mechanical structure that surrounds the fusion plasma. This structure must withstand extreme heat fluxes on the plasma-facing side and effectively remove this heat via flowing molten salt on the other side of the vessel. This vessel must also be replaceable via a remote handling system during regular plant maintenance cycles. Come lead the design of a critical portion of the world's first fusion power plant!

What you'll do

  • Lead a team of mechanical engineers to plan and deliver on the ARC vacuum vessel and connected systems
  • Oversee the full design lifecycle, from initial concept and CAD modeling to hardware procurement and assembly
  • Interface the design of the vacuum vessel with many other systems in the ARC plant, coordinating with other engineering teams to ensure the best overall design for the product
  • Provide hands-on technical leadership to solve complex, multi-disciplinary design challenges and manage risks in new environments and with novel materials
  • Work with the supply chain and materials and processing teams to identify and develop suppliers for the vacuum vessel
  • Proactively manage schedule and budget to deliver a critical component to the ARC fusion power plant
  • Manage all aspects of the group's talent, including hiring, training, and setting clear performance expectations
  • Promote a culture of resilience and grit, ensuring the team consistently follows through on assignments despite technical hurdles

What we're looking for

  • Bachelors Degree in Mechanical Engineering or a closely related degree
  • 10+ years experience in mechanical engineering or closely related fields
  • Experience working on a multi-disciplinary engineering project
  • Experience designing and delivering large metallic structures
  • Experience with structural analysis
  • Experience with fabrication of complex large structures
  • Experience working in dynamic R&D environments, including novel materials and locations
  • Broad knowledge of engineering sufficient to interact with multi-disciplinary engineering teams
  • Knowledge of finite element structural analysis
  • Knowledge of fluid cooling of mechanical structures
  • Ability to adapt to a rapidly changing environment

Bonus points for

  • Experience designing systems operating at high temperature (600C / 1100F)

Must-have requirements

  • Perform activities such as stooping and sitting for extended periods of time
  • Willingness to occasionally travel or work required nights/weekends/on-call
  • Dedication to safety to mitigate hazards that may include heat, cold, noise, fumes, strong magnets, lead, high voltage, and cryogenics

$150,000 - $225,000 a year

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

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.

Apply now

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About the role

August 26, 2026

August 26, 2026

Full time

On-site

Company

US$150,000–225,000 annually

Hydrogen

Commonwealth Fusion Systems

cfs.energy

  •  Devens, Massachusetts, United States

10+ years

UTC-05:00