Principal Safety Methods Engineer

TerraPower LLC.; Bellevue (WA); On-site; USD 168,316 - 252,475; Full time

Benefits offered by this job

Comprehensive Medical and Wellness Benefits

401k Plan

Generous Paid Time Off (PTO)

Job summary

TerraPower LLC. is looking for a Principal Safety Methods Engineer to support the development of thermal-hydraulic analysis methods for the Natrium reactor. The role involves validation, scaling analysis, and collaboration with multidisciplinary teams.

Qualified candidates will hold a relevant degree with 8+ years of experience, demonstrating technical skills in thermal-hydraulic analysis and strong analytical thinking. The position is full-time in Bellevue, Washington, with a competitive salary.

Qualifications

• 8+ years in system-level thermal-hydraulic analysis and code assessment.
• Experience in model-to-test comparison and validation metric development.
• Hands-on experience with experimental thermal-hydraulic data.

Responsibilities

• Support verification and validation for thermal-hydraulic analysis tools.
• Perform scaling analysis for test data applicability.
• Document methodologies for internal design processes.

Skills

System-level thermal-hydraulic analysis

Code assessment

Experimental thermal-hydraulic data

System analysis tools (e.g., RELAP5-3D, TRACE)

Analytical thinking

Technical communication

Education

Degree in Mechanical, Nuclear, or Chemical Engineering

Tools

RELAP5-3D

TRACE

Job description

TerraPower is a nuclear technology company based in Bellevue, Washington. At its core, the company is working to raise living standards globally through a more affordable, secure, and environmentally friendly form of nuclear energy along with innovations in medical isotopes to improve human health.

TerraPower is an Equal Opportunity Employer. We do not discriminate in hiring on the basis of sex, gender identity, sexual orientation, race, color, religious creed, national origin, physical or mental disability, protected Veteran status, or any other characteristic protected by federal, state, or local law.

Principal Safety Methods Engineer

This role supports the development, enhancement, and deployment of plant‑scale thermal‑hydraulic analysis methods and models for the Natrium reactor. Reporting to the Manager, Plant Thermal Hydraulics Methods, the principal engineer supports the creation, improvement and qualification of advanced system-level modeling approaches that enable accurate, robust prediction of plant behavior across operational and transient scenarios.

The position requires expertise in system‑level thermal‑hydraulics, thermal‑fluids behavior, computational methods, and scaling analysis supporting benchmarking computational models against experimental data.

Responsibilities

• Support verification, validation, and uncertainty quantification activities for plant scale thermal-hydraulic analysis tools.
• Develop and execute code assessment plans, including validation matrices, test selection, and quantitative comparison methodologies.
• Perform scaling analysis to evaluate the applicability of test data to reference system conditions, including assessment of similarity criteria and scaling distortion.
• Interpret and apply experimental data from separate effects and integral test facilities to support model validation and closure of technical gaps.
• Define validation needs, develop test requirements, and collaborate closely with test engineering teams to ensure alignment between model gaps and experimental programs.
• Document V&V methodologies, model assumptions, validation results, and uncertainty analyses for internal design processes and regulatory submittals.
• Collaborate with multidisciplinary teams to support plant design, safety analysis, and licensing workflows.
• Apply and improve TerraPower’s SQA and NQA1 modeling quality practices and ensure traceability and configuration control of analysis inputs, models, and results.
• Mentor junior engineers in system modeling, validation methodologies, and best practices in code assessment.

Key Qualifications and Skills

• Degree in Mechanical, Nuclear, Chemical Engineering, or similar field, with 8 plus years in the field of system‑level thermal‑hydraulic analysis and code assessment for nuclear or complex energy systems.
• Demonstrated experience in code assessment, including model-to-test comparison, validation metric development, and uncertainty quantification.
• Hands‑on experience working with experimental thermal‑hydraulic data, including data analysis, uncertainty evaluation, and comparison against system‑level predictions.
• Proficiency with system analysis tools (e.g., RELAP5‑3D, TRACE, SAS, or equivalent) applied to plant‑scale transient and steady‑state evaluations.
• Strong foundation in thermal-fluid and reactor system behavior considerations relevant to advanced reactor designs.
• Experience performing scaling analysis to ensure appropriate translation test-scale phenomena, including application of similarity criteria and detailed scaling distortion impact qualifications.
• Experience developing validation strategies, defining data needs, and coordinating with experimental programs.
• Experience with SQA and NQA‑1 quality assurance practices for modeling workflows is highly preferred.
• Strong analytical thinking, clear technical communication, and the ability to manage multiple validation tasks in parallel.

This position is subject to qualification requirements in accordance with ANSI/ANS 3.1. Candidates must meet the minimum education and experience criteria applicable to the role, including relevant nuclear industry experience where required. Verification of data will be part of the hiring process.

Job Functions

• Motor Abilities: Sitting for extended periods, bending/stooping, grasping/gripping, fine motor control (hands)
• Physical exertion and/or requirements: Minimal, with ability to safely lift up to 25 pounds.
• Special Senses: Visual and audio focused work
• Work Conditions: Stairs, typing/keyboard, standard and/or sitting working environment of >8 hours/day
• Travel required 0‑10%

Job Details

Salary Range: $168,316 - $252,475 (Washington State)

Job Type: Full‑time

• Competitive Compensation
• Salary, eligible to participate in discretionary short‑term incentive payments
• Comprehensive Medical and Wellness Benefits
  • Medical
  • Vision
  • Dental
  • Life and Disability
  • Gender Affirmation Benefits
• 401k Plan
• Generous Paid Time Off (PTO)
  • 21 days of annually accrued PTO
• Generous Holiday Schedule
  • 10 paid holidays
• Relocation Assistance
• Professional and Educational Support Opportunities