Senior Multiphysics Modeling Engineer

What You Will Be Doing

We are seeking a Senior Multiphysics Modeling Engineer to develop and validate coupled thermal-mechanical-fluid models for Helion's fusion hardware. You will bridge simulation and experimental data to inform material selection, component design, and operating limits in one of the most demanding engineered environments in the world.

This role is highly cross-functional, partnering with materials scientists, test engineers, and mechanical designers to ensure modeling directly drives hardware decisions. You will report to our Materials Manager, onsite in Everett, WA.

You Will

• Develop and maintain multiphysics models (primarily in MOOSE) for high-temperature ceramic and metallic components, plasma- and power-facing structures, and pulsed-load systems.
• Simulate coupled thermal, structural, and electromagnetic behavior under rapid cyclic loading, high heat flux, and large temperature gradients, and implement and calibrate constitutive models for fatigue-dominated damage, fracture, and other relevant degradation mechanisms in extreme environments.
• Execute rigorous verification and validation (V&V) by performing convergence studies, co-designing calibration and validation experiments with materials and test engineers, and systematically comparing model predictions to experimental results to quantify discrepancies and refine models, properties, and test plans to close the simulation-experiment gap.
• Apply uncertainty quantification and sensitivity analysis to support life predictions, design margins, and operating envelope definition.
• Translate modeling results into actionable design guidance for materials, joints, components, and inspection strategies.
• Use simulation results to help establish material allowables and operating envelopes for high-temperature metallic and ceramic components.
• Run large-scale simulations in HPC environments and build reproducible, version-controlled modeling workflows.
• Help define a modeling roadmap and standards for key components and failure modes, including expectations for V&V, documentation, and workflow reproducibility as the modeling function grows.

Required Skills

• PhD (or MS with significant experience) in Mechanical Engineering, Nuclear Engineering, Materials Science, Applied Physics, or related field with a computational focus.
• 5+ years of experience in multiphysics finite element or finite volume modeling of coupled thermal-mechanical systems including experience with irradiated materials modeling and materials in severely degrading environments (e.g., plasma, fusion/fission, high-flux/high-dose environments, etc.)
• Proficiency with at least one advanced multiphysics platform (e.g., MOOSE, Abaqus, COMSOL, ANSYS, BISON, OpenMC, MCNP), with willingness to work in MOOSE.
• Demonstrated experience with verification and validation against experimental data.
• Experience running simulations in HPC environments (parallel computing, job scheduling).
• Programming/scripting skills (e.g., Python, C++).
• Demonstrated ability to clearly communicate model assumptions, limitations, and uncertainties to non-modelers and to work effectively with cross-functional teams.

Benefits

Our total compensation package includes benefits, including but not limited to:

• Medical, Dental, and Vision plans for employees and their families
• 31 Days of PTO (21 vacation days and 10 sick days)
• 10 Paid holidays, plus company-wide winter break
• Up to 5% employer 401(k) match
• Short term disability, long term disability, and life insurance
• Paid parental leave and support (up to 16 weeks)
• Annual wellness stipend