Principal Magnet Cryogenics Engineer

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.

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.

• 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, over pressure 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.

• 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).

• 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 &…