Senior Safety Methods Engineer

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. #J-18808-Ljbffr TerraPower LLC.