Senior Safety Methods Engineer

TerraPower LLC.; Bellevue (WA); On-site; USD 138,685 - 208,027; Full time

Benefits offered by this job

Competitive compensation with discretionary short-term incentive payments

Comprehensive medical benefits

401(k) Plan

Generous paid time off (21 days)

Generous holiday schedule (10 paid holidays)

Relocation assistance

Professional and educational support opportunities

Job summary

TerraPower LLC. in Bellevue, Washington is seeking a Senior Safety Methods Engineer to join their team focusing on the design and licensing of the Natrium Demonstration reactor. The role involves developing thermal-hydraulic analysis methods and supporting method qualification through various responsibilities.

Candidates must have a degree in Engineering and at least 3 years of relevant experience. The position offers competitive compensation, including extensive medical benefits and generous paid time off.

Qualifications

• 3+ years of experience in system-level thermal-hydraulic modeling and method development.
• Experience in sensitivity analyses and model gap identification.
• Familiarity with NQA-1 quality assurance for modeling workflows.

Responsibilities

• Develop system-level thermal-hydraulic analysis methods.
• Perform steady-state and transient system-level analyses.
• Support method qualification and develop automated workflows.

Skills

Thermal-hydraulic modeling

Numerical scheme development

Python

MATLAB

Analytical thinking

Education

Degree in Mechanical, Nuclear, Chemical Engineering or related field

Tools

RELAP5-3D

GOTHIC

SAS

Job description

TerraPower is a nuclear technology company based in Bellevue, Washington that aims to raise living standards by providing affordable, secure, and environmentally friendly nuclear energy and medical isotope solutions. Founded in 2006 by Bill Gates and other visionaries, the company is committed to advancing global energy deployment and improving human health through innovation.

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.

Senior Safety Methods Engineer

The Senior Safety Methods Engineer is part of a growing team supporting the design and licensing of the Natrium Demonstration reactor and is primarily responsible for developing methods to perform Licensing Basis Events (LBE) analyses. The role may also contribute subject‑matter expertise to other projects within the TerraPower Sodium Fast Reactor (SFR) Program, including closure model formulation, system transient code development, reactor transient analyses, code benchmarking, scaling analysis, and verification and validation activities. The engineer reports to the Manager of Plant Thermal Hydraulics Methods.

Responsibilities

• Develop system-level 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 fidelity requirements.
• Support method qualification, including numerical verification, applicability envelopes, and performance characterization.
• Formulate and integrate closure models and empirical correlations (e.g., heat transfer, pressure drop, mixing, component‑level physics) into existing frameworks.
• Identify modeling gaps and support method enhancement through sensitivity studies.
• Develop automated workflows and tools for model setup, execution, post‑processing, and repeatable method application.
• Document modeling methodologies, assumptions, applicability, and numerical performance for design processes and licensing support.
• 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.

Key Qualifications and Skills

• Degree in Mechanical, Nuclear, Chemical Engineering, or a related field with 3+ years of experience in system-level thermal‑hydraulic modeling and method development for nuclear or complex energy systems.
• Experience developing or improving analysis methods, including numerical scheme development, closure model formulation, and stability/accuracy optimization strategies.
• Proficiency in system-level thermal‑hydraulic analyses using RELAP5‑3D, GOTHIC, SAS, or equivalent, with ability to extend or tailor modeling approaches.
• Strong foundation in thermal fluids and reactor system behavior relevant to advanced reactor designs.
• Experience in sensitivity analyses and model gap identification to support method development.
• Familiarity with scientific programming and workflow automation (e.g., Python, MATLAB).
• Familiarity with NQA‑1 quality assurance for modeling workflows, including documented methodologies, configuration control, and traceability.
• Strong analytical thinking, clear technical communication, and ability to support multiple development efforts concurrently.
• High degree of trust and integrity, open communication, respect, and teamwork orientation.

Job Details

Job Type: Full-time

Salary Range (Washington State): $138,685 – $208,027

Benefits:

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

Applicants must be U.S. citizens or nationals, as applicants from other countries are subject to U.S. Government export control requirements. The position is available for individuals who can meet these requirements.