Principal Engineer, Safety Methods

TerraPowerBellevue, Washington, United States$168k–$252k/yr

Good fit if

  • You can work a hybrid schedule.
  • You have 12+ years of experience.
  • You can travel 0 to 10% of the time.

Credentials that matter

Skills and tools

  • RELAP
  • GOTHIC
  • SAS
  • Thermal Hydraulics
  • ASME NQA-1
  • Python
  • MATLAB

Required qualifications

  • Degree in Mechanical, Nuclear, Chemical Engineering, or similar field
  • 12+ years of experience in system-level thermal-hydraulic modeling and method development for nuclear or complex energy systems
  • Demonstrated experience developing or improving analysis methods, including numerical scheme development, closure model formulation, and stability/accuracy optimization strategies
  • Experience performing system-level thermal-hydraulic analyses using tools such as RELAP5-3D, GOTHIC, SAS, or equivalent
  • Strong foundation in thermal-fluids and reactor system behavior, including complex thermal-hydraulic phenomena relevant to advanced reactor designs
  • Experience in sensitivity analyses and model gap identification that support method development priorities
  • Familiarity with NQA-1 quality assurance for modeling workflows, including documented methodologies, configuration control, and model traceability
  • Strong analytical thinking, clear technical communication, and ability to support multiple method development efforts in parallel

About this role

Principal Engineer supporting the development and deployment of thermal-hydraulic analysis methods and models for TerraPower's Natrium advanced reactor. This role focuses on system-level thermal-hydraulics and computational methods to enable accurate prediction of plant behavior across operational and transient scenarios, with emphasis on method qualification, closure model integration, and licensing-support documentation.

Responsibilities

  • Develop plant-scale thermal-hydraulic analysis methods, including modeling strategies, numerical approaches, and closure models
  • Perform steady-state and transient system-level analyses to characterize model behavior, assess method performance, and define method fidelity requirements
  • Develop and maintain method qualification plans, including numerical verification, applicability envelopes, and performance characterization
  • Formulate and integrate closure models and correlations (heat transfer, pressure drop, mixing, component-level physics) into existing analysis frameworks
  • Identify modeling gaps and drive method enhancement priorities using Phenomena Identification and Ranking Table (PIRT), sensitivity studies, and multi-physics needs
  • Develop automated workflows and tools for model setup, execution, post-processing, and repeatable method application
  • Collaborate with test engineering to define data needs that inform method development and guide model formulation
  • Document modeling methodologies, assumptions, method applicability, and numerical performance for design and licensing-support activities
  • Work across disciplines to ensure thermal-hydraulic methods integrate effectively with plant design, safety analysis, and coupled simulation workflows
  • Apply and improve TerraPower's SQA and NQA-1 modeling practices, ensuring traceability, configuration control, and reproducibility
  • Mentor junior engineers in numerical method development, system modeling, and modern computational analysis practices

Preferred qualifications

  • Familiarity with scientific programming and workflow automation (Python, MATLAB)

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Principal Engineer, Safety Methods

TerraPower · $168k–$252k/yr

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