Director of ModSim

At Valar Atomics, we're redefining what's possible in energy. Our mission is to make clean, high-temperature nuclear power scalable—unlocking abundant energy for industry, hydrogen, and next-generation manufacturing. We are a team of builders, engineers, and operators who believe nuclear energy should be fast to deploy, factory-made, and built for the real world. Our first pilot plant in Orangeville, Utah will demonstrate how advanced nuclear systems and fuel fabrication can power the future. Joining Valar Atomics means becoming part of a company where autonomy, ownership, and impact exist at every level.

The Team

The ModSim Engineering Group is a dynamic analysis and engineering group that provides the analytical foundation for reactor and plant design, delivering high-fidelity computational analysis, integrated directly into the engineering design process.

The group responsibilities spans:

• Neutronics and reactor design;
• Thermal-hydraulics systems analysis covering steady-state and transient performance of the complete system; and
• Computational fluid dynamics and finite element analysis for detailed flow, thermal, and structural integrity assessment.

ModSim works alongside the engineering and licensing organizations and develops and maintains the models that underpin design basis definition, transient and accident analysis, safety case development and regulatory submittals, applying rigorous verification, validation and uncertainty quantification throughout. The group's responsibilities extend beyond prediction: models are benchmarked against test data and against operating data from research and demonstration reactors in construction and service, closing the loop between simulation, as-built plant performance, and the continuous improvement of the company's analytical methods and business case.

The Role

The Director of ModSim leads VALAR Atomics’ modeling, simulation, and analysis organization across CFD, FEA, thermal-hydraulics, and nuclear engineering, and is accountable for ensuring that analysis supports the design process and outputs that get built.

Reporting to the CNO / VP of Engineering, the Director of ModSim owns the strategy, quality, throughput, resourcing, and budget of the group; the multiphysics integration and verification-and-validation (V&V) consistency that bind the disciplines together; and the licensing-grade defensibility of every deliverable under a nuclear quality program (i.e. NQA-1, 10 CFR 50 Appendix B, ASME V&V 10/20/30).

In a dynamic, speed-driven start-up racing to deploy reactors at scale, the ModSim Director is equal parts technical authority, org-builder, systems thinker, and dot-connector, growing the team from a small core, automating the simulation-to-design workflow, and wiring ModSim into design, manufacturing, licensing, and construction so that models become steel, on schedule and to code. This is a hands-on-enough leader who is as comfortable interrogating a Flownex transient or a neutronics depletion run as standing on a fabrication floor asking why the as-built diverges from the model.

Key Responsibilities

The Director carries seven areas of accountability, spanning technical leadership, people, integration, reporting, and relentless optimization of output rate, speed, and quality:

• Technical leadership across the four core disciplines. Set the analysis strategy, methods, and standards for CFD, FEA, thermal-hydraulics, and neutronics; own multiphysics integration, cross-discipline data-exchange conventions, configuration control, and end-to-end V&V so the coupled picture is consistent and defensible.
• Close the loop from model to build hardware. Ensure analysis directly supports design outputs, i.e., sized components, qualified structures, validated systems, and stays connected through procurement, fabrication, construction, and commissioning; drive validation and design-for-manufacture feedback so the digital model and the physical plant stay in alignment.
• Build, grow, and develop the team. Recruit, mentor and retain Stream/Discipline Leads and their analysts; scale a small start-up core into a high-performing multidisciplinary group; engage SMEs and external partners; create the culture, career paths and technical bar for the organization.
• Integrate ModSim within the wider engineering enterprise. Partner with design, systems engineering, manufacturing, licensing/safety, project management, and construction so that simulation is embedded in the design process rather than bolted on; make ModSim the trusted, single source of analytical truth across groups.
• Report to and advise executive leadership. Serve as the senior simulation interface to the CNO / VP of Engineering and executive team; translate complex analysis into clear, decision-grade guidance on risk, schedule, cost, and design choices.
• Relentlessly optimize output rate and quality. Drive throughput and rigor together via workflow automation, scripting, templated and parametric models, digital-thread / digital-engineering tooling, HPC scaling, and reusable V&V, etc., so the group delivers more, faster, without compromising nuclear-grade quality.
• Own quality, licensing-readiness, tooling, and budget. Hold accountability for the nuclear QA and V&V framework (NQA-1, 10 CFR 50 Appendix B, ASME V&V 10/20/30) and licensing-grade defensibility (NRC 10 CFR Part 50/52/53, ASME codes); manage the simulation software portfolio, HPC resources, vendor relationships and group

Basic Qualifications

• Master’s degree in engineering (MSc/MEng), or equivalent work experience required — Nuclear, Mechanical, Aerospace, or a closely related discipline; PhD strongly preferred.
• 15+ years in engineering simulation and analysis, with substantial multidisciplinary leadership and team / program management (a strong 10+-year track record with exceptional build-to-deployment credentials will be considered).
• Demonstrated experience taking modeling and analysis through to design, constructed and/or operating hardware – not solely paper studies.
• Depth in at least one of CFD, FEA, thermal-hydraulics or neutronics, with the breadth to direct and critically review the others.
• Experience working under a formal quality program (NQA-1, ISO 9001, 10 CFR 50 Appendix B or equivalent) and within a regulated environment (NRC, ASME, or comparable such as naval nuclear, aerospace/FAA, or DoD).
• S. Person status (or ability to meet U.S. nuclear export-control requirements under 10 CFR Part 810 / ITAR-EAR) and ability to obtain any required DOE/NRC access or clearance.

Preferred Skills and Experience

A strong candidate will bring most of the following – the blend of computational depth, engineering breadth, and delivery credibility this role demands:

Simulation & computational engineering

• Hands-on mastery of one or more of: Ansys Fluent/CFX (CFD), Ansys Mechanical (FEA), Flownex SE, RELAP5-3D, TRACE, and/or MELCOR (thermal-hydraulic systems), and neutronics tools (OpenMC, SCALE, Serpent, MCNP); ability to direct and review all four.
• Multiphysics coupling, verification, validation, and uncertainty quantification (ASME V&V 10/20/30); model configuration control and traceability.
• Systems engineering and digital engineering / digital-thread practice; workflow automation and scripting (Python, APIs, journaling) and parametric / templated modeling; HPC at scale.
• Engineering design and the design-to-build lifecycle: design-for-manufacture, tolerancing, procurement, fabrication, construction support and commissioning.
• Thermal-hydraulics and heat transfer; turbomachinery; heat exchangers; high-pressure piping (ASME B31, Section III); control and dynamics / transient plant behavior.
• Nuclear reactor design (HTGR / gas-cooled experience a major plus: helium coolant, TRISO fuel, graphite core, high-temperature materials, Brayton / supercritical-CO₂ power conversion, process-heat applications).
• Manufacturing and construction realities – what it actually takes to fabricate, weld, inspect, assemble and integrate a plant.
• Nuclear quality assurance (NQA-1, 10 CFR 50 Appendix B, ISO 9001) and software QA.
• Nuclear licensing and safety (NRC 10 CFR Part 50/52/53), ASME code application (Section III, VIII, B31), and interaction with regulators and external reviewers.
• A portfolio of successfully delivered projects — ideally analysis-led designs that were built and operated — delivered to schedule and quality.
• Leadership: recruiting and growing technical teams, mentoring, stakeholder management, and the gravitas to represent the company to regulators, partners, and investors.
• Experience under a nuclear or regulated quality program (NQA-1, ISO 9001, 10 CFR 50 Appendix B) and exposure to NRC/ASME environments.
• Track record of mentoring and leading a multidisciplinary technical systems analysis team.

What We Offer

• Equity ownership in a rapidly growing advanced energy company
• Unlimited PTO
• Free daily lunch and dinner provided onsite
• Generous PPE stipend
• High-impact startup environment with significant ownership and autonomy
• Opportunities for rapid career growth and internal advancement
• Direct collaboration with experienced operators, engineers, and industry leaders
• The opportunity to help build and scale transformative energy technology from the ground up

Equal Employment Opportunity Statement

Valar Atomics is an equal opportunity employer. We consider all qualified applicants without regard to race, color, religion, sex, gender identity, sexual orientation, national origin, age, disability, veteran status, or any other protected status under applicable law.

We are committed to providing a workplace free of discrimination and harassment and will provide reasonable accommodation as required by law.

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

$225,000 - $300,000 USD