Thea Energy

Develops fusion power via planar-coil stellarators

Principal Magnet Cryogenics Engineer

Thermal & Fluids EngineeringConfirmed live in the last 24 hours

Full-timeKearny, NJ, USAIn-person

About the Job

Requirements

At least 10 years of direct experience in cryogenic engineering and thermal-hydraulic design for superconducting magnet systems, primarily using HTS tape or cable architectures such as REBCO or BSCCO.
A proven track record owning large-scale magnet work packages exceeding $10 million within fusion energy programs or major scientific facilities.
Expertise in high-current cabled HTS configurations, including Cable-in-Conduit Conductors and stacked-tape conductors, and forced-flow cooling strategies.
Experience taking at least one major superconducting magnet or cryogenic system from initial concept through initial cool-down and operational validation.
Deep familiarity with cryogenic-temperature pressure-vessel standards, including ASME BPVC Section VIII, EN 13445, and B31.3, and cryogenic safety standards including ISO 21010 and CGA.
Solid understanding of REBCO coated-conductor critical surfaces, strain sensitivity, thermal-margin assessment, and current-sharing regimes.
Mastery of low-temperature fluid dynamics and thermophysical properties for gaseous helium and sub-cooled liquid nitrogen, using database tools.
Deep knowledge of transient thermal analysis, including AC losses, nuclear volumetric heating, heat-leak budgets, and conduction/radiation thermal shielding and multilayer insulation design.
Extensive knowledge of low-temperature thermometry, including Cernox, TVO, and optical fibers/FBG; cryogenic flow meters; pressure transducers; and cryogenic valve telemetry.
Proficiency in finite element analysis and thermal-hydraulic system modeling tools, such as COMSOL Multiphysics, ANSYS Thermal/CFD, and MATLAB/Simulink.
Ability to write system requirement documents and interface control documents and lead major design reviews, including CoDR, PDR, and CDR.
Demonstrated ability to lead cross-functional engineering teams spanning structural, electrical, vacuum, and systems disciplines and mentor junior magnet and cryogenic engineers.
Mastery of failure mode and effects analysis applied to cryogenic system failures, loss of vacuum, and runaway quench scenarios.

Responsibilities

Lead the complete lifecycle of large-scale HTS fusion magnet cryogenic systems, from conceptual, preliminary, and detailed design through qualification, fabrication, assembly, commissioning, and decommissioning.
Design, model, and validate gaseous-helium or sub-cooled-liquid-nitrogen thermal management systems for high-field HTS cabled and stacked-tape conductors.
Perform dynamic thermal-hydraulic analysis, transient load modeling for nuclear heating, AC losses, eddy currents, and ramp rates, and margin calculations for operational and fault conditions.
Own the cryogenic response strategy for quench events, including rapid helium expansion, overpressure-relief sizing, burst-disc integration, and thermo-mechanical stress containment.
Define requirements for megawatt-class cryogenic plants, cold compressors, heat exchangers, sub-coolers, helium distribution boxes, and low-heat-leak transfer lines.
Oversee cryogenic thermal management for high-current demountable or permanent HTS joints and conduction-cooled hybrid HTS/LTS gas-cooled current leads rated at 60 kA or more.
Manage major subcontracts for large-scale cryogenic infrastructure, conductor fabrication, pressure vessels, and vacuum-insulated systems such as cryostats.
Plan and execute full-scale cryogenic and high-current magnet test campaigns, leading cool-down, steady-state operation, quench mitigation, and warm-up procedures.

Salary Range: 190000 to 215000 (Currency: USD) (Pay period: per-year-salary)

About Thea Energy:

Thea Energy is leveraging recent breakthroughs in stellarator physics and engineering to create a faster and simpler approach to commercializing fusion energy. The company is reinventing the stellarator using computer-controlled arrays of planar coils thereby replacing the intricate, complex modular magnets required in all other stellarator architectures. Thea Energy is on a mission to create a limitless source of zero emission energy for a sustainable future.

Position Overview:

We are seeking a Principal Magnet Cryogenics Engineer with over 10-15 years of industry experience to lead the complete program lifecycle—from concept through commissioning—of large-scale cabled High-Temperature Superconducting (HTS) magnet systems for next-generation fusion reactors.

In this role, you will hold end-to-end technical ownership for the cryogenic design, thermal-hydraulic modelling, forced-flow cooling distribution, and cryogenic integration of large-scale CICC (Cable-in-Conduit Conductor) or advanced stacked-tape HTS magnets. You will bridge megawatt scale cryogenic plant engineering with microscopic thermal-hydraulic magnet behaviour, leading multi-disciplinary teams through multi-million-dollar hardware deliverables.

Key Responsibilities:

Program Lifecycle Ownership: Lead the complete lifecycle (Conceptual, Preliminary, Detailed Design, Qualification, Fabrication, Assembly, Commissioning, and Decommissioning) for large-scale HTS fusion magnet cryogenic systems.
Cryo-Thermal System Architecture: Design, model, and validategaseous helium (gHe), or sub-cooled liquid nitrogen (sLN2) thermal management systems tailored to high-field HTS cabled conductors (stacked HTS conductors).
Thermal-Hydraulic Modeling: Perform dynamic thermal-hydraulic analysis, transient load modelling (nuclear heating, AC losses, eddy currents, ramp rates), and margin calculations under operational and fault conditions.
Quench & Fault Management: Own the cryogenic response strategy during quench events, including rapid helium expansion, overpressure relief sizing, burst disc integration, and thermo-mechanical stress containment.
Large-Scale Infrastructure & Plant Integration: Define requirements for mega-watt class cryogenic plants, cold compressors, heat exchangers, sub-coolers, helium distribution boxes (valve boxes), and low-heat-leak transfer lines.
Joints & Current Leads: Oversee cryogenic thermal management for high-current demountable or permanent HTS joints and conduction-cooled hybrid (HTS/LTS) gas-cooled current leads (60+ kA).
Vendor & Subcontractor Governance: Manage major sub-contracts for large-scale cryogenic infrastructure, conductor fabrication, pressure vessels, and vacuum insulated systems (cryostats).
V&V and Commissioning: Plan and execute full-scale cryogenic and high-current magnet test campaigns, leading cool-down, steady-state operation, quench mitigation, and warm-up procedures.

Required Experience:

10-15+ Years of Direct Experience in cryogenic engineering and thermal-hydraulic design for superconducting magnet systems, with a primary focus on HTS tape/cable architectures (REBCO/BSCCO).
Large-Scale Fusion/Physics Program Delivery: Proven track record of ownership over large-scale (> $10M+) magnet work packages within fusion energy programs (e.g., W7x, ITER, JT60SA, KSTAR, DEMO) or major scientific facilities (e.g., CERN, FERMILAB).
Cabled HTS Architecture: Demonstrated expertise in high-current (tens of kA) cabled HTS configurations (e.g., Cable-in-Conduit Conductors, stacked tape conductors) and forced-flow cooling strategies.
Full Lifecycle Track Record: Experience taking at least one major superconducting magnet or cryogenic system from initial concept through initial cool-down and operational validation.
Regulatory & Code Compliance: Deep familiarity with pressure vessel standards applied to cryogenic temperatures (ASME BPVC Section VIII, EN 13445, B31.3) and cryogenic safety standards (ISO 21010/CGA).

Technical Knowledge

HTS Material Physics: Solid understanding of critical surfaces for REBCO coated conductors, strain sensitivity, thermal margin assessment, and current sharing regimes.
Cryogenic Fluids & Thermophysical Properties: Mastery of low-temperature fluid dynamics (gHe, sLN2) using database tools.
Transient Thermal Analysis: Deep domain knowledge of AC losses (coupling, hysteresis, flux creep) nuclear volumetric heating, heat-leak budgets, and conduction/radiation thermal shielding (MLI design).
Instrumentation & Controls: Extensive knowledge of low-temperature thermometry (Cernox, TVO, optical fibers/FBG), cryogenic flow meters, pressure transducers, and cryogenic valve telemetry.

Skills & Competencies

Computational Tools: Proficiency in finite element analysis (FEA) and thermal-hydraulic system modeling tools (e.g., COMSOL Multiphysics, ANSYS Thermal/CFD, MATLAB/Simulink).
System Engineering & Requirements Flowdown: Capability to write clear system requirement documents (SRDs), interface control documents (ICDs), and lead major design reviews (CoDR, PDR, CDR).
Leadership & Team Mentorship: Demonstrated ability to lead cross-functional engineering teams (structural, electrical, vacuum, systems) and mentor junior magnet/cryogenic engineers.
Strategic Risk Mitigation: Mastery of FMEA, applied to cryogenic system failures, vacuum loss (loss of vacuum/L VAC), and runaway quench scenarios.

#LI-RD1

Company Benefits:

Comprehensive health benefits (e.g. medical/dental/vision)

Employee equity stock options

20 days PTO

It’s not necessary to meet all of the skillsets outlined above. Please feel free to send us a note and tell us why you would still be a great fit for this role or Thea Energy.

Diversity and Inclusion:

Thea Energy is an equal opportunity employer committed to creating a company of diverse backgrounds. By creating a diverse environment, we will bring new ideas and approaches to solving some of the world’s hardest (and most important) problems. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, gender, sexual orientation, gender identity or expression, national origin, family or marital status, age, disability, veteran’s status, or other characteristic protected by applicable laws and regulations.

About the Company

Thea Energy

Develops fusion power via planar-coil stellarators

Thea Energy develops fusion-based power technology to provide scalable, zero-emission baseload electricity for utilities and heavy industry. Its approach uses a reimagined stellarator with flat, planar superconducting coils controlled by software-defined systems, replacing the traditional complex magnet geometry to lower costs and improve serviceability. Its Eos neutron-source device and Helios commercial power plant concept illustrate a pipeline from research to grid-ready power, backed by DOE milestones and public-private partnerships. The company aims to commercialize fusion as a dependable grid-level energy source and win long-term offtake agreements with utilities and large customers.

Company size: 51-200
Company stage: Grant
Total funding: $145.8M
Headquarters: Princeton, NJ
Founded: 2022

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