Principal Magnet Cryogenics Engineer

About the role

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.

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 validate gaseous 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