Senior Thermal-Hydraulics Analysis Engineer (Nuclear)

Location: Torrance, California, United States; onsite. Applicants must be legally authorized to work in the United States as a U.S. citizen or lawful permanent resident.

Salary: $151,000–$185,000 USD per year

Company

hirify.global develops scalable, high-temperature nuclear power systems for industrial applications, hydrogen production, and next-generation manufacturing.

What you will do

• Build, run, validate, and maintain integrated Flownex SE network models for reactor loops, balance of plant, and power-conversion cycles.
• Analyze steady-state and transient plant behavior, including start-up, shutdown, load-following, loss-of-flow, and trip scenarios.
• Characterize and size pumps, compressors, heat exchangers, valves, and turbomachinery while evaluating Brayton and supercritical-CO₂ cycle performance.
• Provide system boundary conditions to CFD and FEA teams and integrate loss coefficients, heat-transfer data, supplier information, and neutronics power distributions.
• Produce NQA-1 calculation packages and system design-basis documentation supporting safety analysis, regulator reviews, and customer discussions.
• Establish modeling standards, component libraries, and templates; mentor engineers and support systems-work planning.

Requirements

• Bachelor’s degree or higher in Mechanical, Nuclear, Chemical, or Aerospace Engineering with emphasis on thermodynamics, heat transfer, or thermal-hydraulics systems.
• 5+ years of professional thermal-hydraulics or plant-systems analysis experience, including lead responsibility for integrated system or cycle models.
• Strong applied thermodynamics, heat transfer, fluid mechanics, transient simulation, and closed-loop power-cycle design experience.
• Experience with Flownex SE or a comparable systems/transient code such as RELAP5, TRACE, GOTHIC, MELCOR, Modelica/Dymola, Aspen HYSYS Dynamics, Thermoflow, or GateCycle.
• Experience with heat-exchanger design and rating, turbomachinery and pump performance, control-system representation, and scripting or workflow automation.
• Experience with nuclear or regulated quality programs such as NQA-1, ISO 9001, or 10 CFR 50 Appendix B, and exposure to NRC or ASME environments.

Nice to have

• Master’s degree or higher in a relevant engineering discipline.
• Experience with CoolProp, REFPROP, or other property libraries and equations of state.
• Experience with helium, molten salt, sodium, or CO₂ working fluids.
• Experience with reactor thermal-hydraulics, decay heat, or natural-circulation scenarios.

Culture & Benefits

• High-impact startup environment with significant autonomy, ownership, and responsibility.
• Competitive base salary, equity ownership, and comprehensive medical benefits.
• Unlimited paid time off and opportunities for rapid career growth.
• Free daily lunch and dinner provided onsite, plus a generous PPE stipend.
• Direct collaboration with experienced operators, engineers, and industry leaders.