Role
Valar Atomics is hiring a Senior Thermal-Hydraulics Analysis Engineer in its ModSim (Model & Simulation) Engineering Group. The engineer leads system-level, one-dimensional network modelling of the reactor's primary and secondary loops, balance of plant and power-conversion cycles in Flownex SE, turning the results into inputs for component sizing, control philosophy, cycle optimization and the wider design and safety effort.
Responsibilities: The role builds and maintains integrated plant models for steady-state and transient analysis, including start-up and shutdown, load changes, loss of flow and trips. It sizes pumps, compressors, heat exchangers, valves and turbomachinery and evaluates Brayton and supercritical-CO2 cycles. The engineer exchanges boundary conditions and coefficients with the CFD and FEA work, produces calculation packages and design-basis documentation under NQA-1, provides inputs to safety analysis, leads model verification and validation, standardizes Flownex methods and mentors junior analysts.
Requirements: A bachelor's degree or higher in mechanical, nuclear, chemical or aerospace engineering with emphasis on thermodynamics, heat transfer or thermal-hydraulic systems, and at least five years of professional thermal-hydraulics or plant-systems analysis experience, including lead responsibility on integrated system or cycle models.
Preferred experience: A master's degree in one of those fields; Flownex SE expertise, or depth in a comparable code such as RELAP5, TRACE, GOTHIC, MELCOR, Modelica/Dymola or Aspen HYSYS Dynamics with willingness to adopt Flownex; closed-loop power-cycle and heat-exchanger design; reactor transient, decay-heat and natural-circulation simulation; helium, molten-salt, sodium or CO2 working fluids; and work under NQA-1, ISO 9001 or 10 CFR 50 Appendix B.
Working arrangements: Applicants must be legally authorized to work in the United States as a U.S. citizen or lawful permanent resident.
Snapshot
| Employer | Valar Atomics |
| Workplace | Torrance, California, US |
| Onsite | Not specified |
| Employment type | — |
| Salary | $151,000–$185,000 USD |
| Date posted | 2026-07-29 |
| Expires | — |
| Verified | 2026-10-06 |
Sources & verification
The original publication date is exactly as posted on the employer ATS — no substitutions. The links below are the same ATS pages we used to verify this listing; the dates come from when we last checked them.
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