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Valar Atomics is building advanced nuclear systems to deliver clean, scalable, high-temperature power for industrial applications, hydrogen production, and next-generation manufacturing. The company is developing a pilot plant in Utah and is backed by Series A funding.
The Senior Thermal-Hydraulics Analysis Engineer will lead system-level thermal-hydraulics modeling within the Models & Simulations Engineering Group. This role owns the design, development, and validation of integrated plant models using Flownex SE that capture both steady-state performance and transient behavior across the reactor's primary and secondary loops, balance of plant, and power-conversion cycles (Brayton and supercritical-CO₂ architectures).
Key responsibilities include:
- Building, running, and maintaining integrated Flownex SE network models for steady-state and transient analysis
- Characterizing and sizing critical components (pumps, compressors, heat exchangers, valves, turbomachinery) and optimizing cycle performance
- Analyzing plant transients and control response (start-up/shutdown, load-follow, loss-of-flow, trip scenarios) and providing system boundary conditions to CFD and FEA teams
- Producing calculation packages and system design-basis documentation under NQA-1 standards; interfacing with safety analysis, CFD models, and neutronics teams
- Leading verification and validation of system models, establishing modeling standards, supporting regulatory reviews, and mentoring junior analysts
- Standardizing Flownex modeling methods, component libraries, and templates across the engineering organization
The ideal candidate holds a Bachelor's degree (or higher) in Mechanical, Nuclear, Chemical, or Aerospace Engineering with 5+ years of professional thermal-hydraulics and plant-systems analysis experience, including lead responsibility on integrated system or cycle models. Expertise in Flownex SE is strongly preferred; experience with RELAP5, TRACE, GOTHIC, MELCOR, Modelica/Dymola, or similar transient codes is valuable. Strong applied knowledge of thermodynamics, heat transfer, fluid mechanics, heat-exchanger design, turbomachinery characterization, and control-system representation is essential. Experience with advanced working fluids (helium, molten salt, sodium) and property libraries (CoolProp, REFPROP) is a plus.
