Staff CFD Analysis Engineer

About the role

The Senior CFD Analysis Engineer translates complex flow and heat-transfer problems into defensible models that support safety, performance, and licensing. The position operates within the Modelling & Simulation Engineering Group and interfaces with thermal-fluid, structural, and neutronics teams. You will own the setup, execution, and interpretation of high-fidelity computational fluid dynamics simulations for advanced reactor systems. This role requires you to bridge detailed physics with engineering judgment to produce analyses that regulators and stakeholders can trust. You will work directly with thermal-fluid specialists, structural analysts, and reactor physicists to ensure that simulation outputs inform critical design and safety decisions. A key part of your responsibility is to convert ambiguous requirements into rigorous analysis plans that address uncertainty, risk, and verification needs. You will also translate highly technical results into clear narratives and visualizations for both technical and non-technical audiences.

Key facts

What you'll do

Plan and execute high-fidelity CFD and conjugate heat transfer analyses for advanced reactor thermal-hydraulics scenarios.

Develop and maintain verification and validation strategies following ASME V&V 20, including grid convergence studies and uncertainty quantification.

Lead the application of turbulence modeling approaches such as RANS k-ε, k-ω SST, and scale-resolving methods like LES and DES for reactor-relevant flows.

Perform multiphase and species transport modeling for coolant behavior in systems involving helium, molten salt, and liquid metals.

Automate analysis workflows using Python scripting, UDFs, and journaling to reduce manual effort and improve reproducibility.

Coordinate with systems engineers to couple CFD models with system-level codes and with structural analysts to assess thermal stresses and mechanical integrity.

Conduct GCI studies and support licensing activities by ensuring traceability, documentation, and adherence to nuclear quality programs like ASME NQA-1 and 10 CFR 50 Appendix B.

Mentor junior analysts and lead technical reviews within the Modelling & Simulation team to elevate overall group capability.

Investigate and implement advanced thermal-hydraulics methods for HTGR, SFR, MSR, and micro-reactor technologies.

Maintain and enhance HPC workflows to ensure efficient and robust simulation execution on large-scale computational resources.

Support the creation of defensible safety analyses by validating simulations against experimental data and regulatory benchmarks.

Drive continuous improvement in modeling practices by tracking emerging methods in scale-resolving simulation and reactor thermal-hydraulics.

Ensure that all analysis products meet stringent documentation standards and are suitable for regulatory review.

Collaborate cross-functionally to integrate thermal, fluid, and neutronics insights into coherent system-level models.

Represent Valar Atomics in external technical discussions and internal knowledge-sharing sessions to promote best-in-class simulation practices.

Requirements

Hold a Bachelor's degree (or higher) in Mechanical, Aerospace, or Nuclear Engineering, or a closely related field.

Bring 8+ years of professional, production-grade CFD analysis experience in nuclear or other high-consequence industries.

Demonstrate strong grounding in turbulence modeling, including RANS k-ε, k-ω SST, and experience with LES or DES approaches.

Show proven ability in conjugate heat transfer modeling for solid-fluid interactions and thermal stress considerations.

Practice verification and validation per ASME V&V 20, including guidance on GCI studies and error estimation.

Have experience operating under a nuclear or regulated quality program such as ASME NQA-1, ISO 9001, and 10 CFR 50 Appendix B.

Possess deep reactor thermal-hydraulics domain knowledge, including natural circulation, passive cooling mechanisms, and coolant behavior for helium, molten salt, and liquid metal coolants.

Apply scripting and automation using Python, UDFs, and journaling tools to streamline analysis workflows and ensure repeatability.

Have hands-on HPC experience, including job submission, post-processing, and performance tuning on clusters or cloud compute resources.

Show a track record of mentoring and leading technical analysis within a team, including reviews, knowledge transfer, and junior development.

Demonstrate ability to couple CFD with systems codes and structural FEA for integrated thermal-fluid and mechanical analysis.

Exhibit experience with advanced-reactor thermal-hydraulics such as HTGR, SFR, MSR, and micro-reactors, which is a plus but not required.

Maintain strong written and verbal communication to explain technical decisions to both experts and non-specialists.

Commit to adhering to regulatory expectations and producing traceable, auditable analysis artifacts.

Nice to have

Experience with Ansys Fluent, Flownex, and finite-element tools for high-fidelity thermal-fluid and structural analysis.

Familiarity with nuclear quality programs and regulatory traceability specific to NRC or ASME regulatory environments.

Background in mentoring and cross-team collaboration in fast-growing technology companies.

Practical notes

United States citizenship or lawful permanent residency is required.

Standard employment terms apply, including at-will employment and background checks as required by law.

Typical interview steps include a recruiter screen, technical rounds, a take-home task, and final interviews focused on team fit.

Interviewers look for how you break down unfamiliar problems, not just whether you reach the answer.

Career growth

Engineering careers usually progress from individual contributor to senior, staff, and principal levels. Some engineers move into management and lead teams of five to twenty people. Others stay on the technical track. Growth follows demonstrated impact, not tenure alone. A typical engineering ladder has clear levels with defined expectations for scope, quality, and mentorship. Moving up usually requires owning outcomes end to end rather than completing assigned tickets.