Senior Thermal-Hydraulics Analysis Engineer

The role

The Senior Thermal-Hydraulics Analysis Engineer leads system-level thermal-hydraulics modelling of reactor loops and power-conversion cycles using Flownex SE. This role builds and validates integrated plant models to inform component sizing, control philosophy, and cycle optimization.

What you will do

• Build, run and maintain integrated Flownex SE network models of primary/secondary loops, balance of plant and power-conversion cycles.
• Characterize and size components like pumps, compressors, heat exchangers, valves, and turbomachinery.
• Evaluate cycle performance and optimization across Brayton and sCO2 architectures.
• Analyze plant transients and control response.
• Provide system boundary conditions to CFD and FEA streams.
• Produce calculation packages and system design-basis documentation under NQA-1.
• Provide inputs to safety analysis and interface with CFD models and neutronics power distributions.
• Lead verification and validation of system models.
• Set systems-modelling standards and support regulator/customer reviews.
• Mentor engineers and train junior team members.

Required qualifications

• 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 / plant-systems analysis experience, including lead responsibility on integrated system or cycle models.

Nice to have

• Master’s degree (MSc/MEng) or higher in Mechanical, Nuclear, Chemical or Aerospace Engineering with emphasis on thermodynamics, heat transfer or thermal-hydraulics systems.
• Flownex SE expertise strongly preferred; otherwise demonstrable depth in a comparable systems/transient code (RELAP5, TRACE, GOTHIC, MELCOR, Modelica/Dymola, Aspen HYSYS Dynamics, Thermoflow / GateCyc
• Strong applied thermodynamics, heat transfer, and fluid mechanics; closed-loop power-cycle design (Brayton, supercritical-CO2).
• Heat-exchanger thermal/hydraulic design and rating; turbomachinery and pump performance characterization; control-system representation.
• Transient and dynamic simulation, including reactor thermal-hydraulics and decay-heat / natural-circulation scenarios.
• Property libraries / equations of state (e.g., CoolProp / REFPROP) and helium, molten-salt, sodium, or CO2 working fluids a strong plus.
• Experience under a nuclear or regulated quality programme (NQA-1, ISO 9001, 10 CFR 50 Appendix B) and exposure to NRC/ASME environments.
• Scripting/automation of work within defined workflows and quality assurance frameworks.
• Track record of mentoring and leading technical systems analysis within a team.

Benefits

• Competitive base salary
• Equity ownership
• Comprehensive medical benefits
• Unlimited PTO
• Free daily lunch and dinner provided onsite
• Generous PPE stipend

Before you apply

• Applicants must be legally authorized to work in the United States as a U.S. citizen or lawful permanent resident (green card holder).

About the company

Valar Atomics aims to make clean, high-temperature nuclear power scalable. Their first pilot plant will be in Orangeville, Utah.