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Molten Salt Engineer

Commonwealth Fusion Systems

Job Location:

Devens, MA - USA

Yearly Salary: USD 70000 - 120000

Posted: 4 September 2026 (Yesterday)

Application Deadline: 2 December 2026

Vacancies: 1 Vacancy

Job Summary

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 were designing and building commercially viable fusion power plants. And were working with policymakers suppliers and many others to build the energy industry of the future.

Were in the best position to make it happen. Since 2018 weve raised $4 billion of capital making us the largest and leading fusion company in the world.

Now were looking for more thinkers doers builders and makers to join us. People wholl bring new perspectives solve tough problems and thrive as part of a team.

If thats you and this role fits we want to hear from you.

Join the power movement as a Molten Salt Engineer

Salt chemistry is a critical driver of corrosion hydrogen speciation and material behavior under irradiation. As the Blanket System team scales up to larger systems maintaining precise control over salt chemistry is vital. We are seeking an entry-level Molten Salt Engineer to support our experimental testing operations. Initially you will focus on executing standard operating procedures (SOPs) conducting routine materials testing and maintaining rigorous quality controls. As you build familiarity with our systems your role will expand to include experimental design test cell design and construction and leading projects in materials corrosion and blanket health monitoring. Ideal candidates will have a background in chemistry chemical engineering or a related discipline.

The Blanket System team has a strong culture of teamwork supportive safety culture and pragmatic risk management. We are looking for an engineer who will fit and actively contribute to this culture.

What youll do:

Perform corrosion testing of novel materials in molten salts
Perform device testing in molten salts to obtain statistics on device performance
Design and build new test cells for molten salt R&D
Assist with lab maintenance and upkeep
Write and modify SOPs for safe handling of hazardous chemicals including fluoride salts (FLiBe)

What were looking for:

Bachelors degree in Chemistry Chemical Engineering Materials Engineering Nuclear Engineering Mechanical Engineering or similar field
0-2 years of work experience
Experience with R&D work in a chemical or engineering laboratory
Experience working with safety systems for hazardous chemicals
Ability to learn new skills/subject matter quickly
Ability to work effectively in a multidisciplinary team of engineers scientists technical staff and others
Ability to clearly express and critique ideas
Great communication and organizational skills
Strong problem solving skills ability to approach new problems with creativity

Bonus points for:

High temperature chemistry
Molten salts
Electrochemistry
Ceramics
Python MATLAB or equivalent for data analysis
Building and commissioning new laboratory equipment
CAD software

Must-have requirements:

Ability to occasionally lift up to 50 lbs
Perform activities such as sitting typing standing stooping or climbing for extended periods of time
Dedication to safety to mitigate industrial hazards that may include heat cold noise fumes strong magnets lead (Pb) high voltage and cryogenics
Willingness to travel or work required nights/weekends/on-call occasionally

$70000 - $120000 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

#LI-Onsite

At CFS we excel in fast-paced environments driven by our values of integrity execution impact and self-critique. As we grow were 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.

Required Experience:

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