Principal Safety Methods Engineer

About the role

TerraPower is a nuclear technology company based in Bellevue, Washington. The company focuses on developing innovative nuclear energy solutions and medical isotopes to improve global living standards. Founded in 2006 by Bill Gates and a group of visionaries, TerraPower aims to lead in new nuclear technologies and foster innovation in the nuclear field.

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.

Qualifications and Skills

• Degree in Mechanical, Nuclear, Chemical Engineering, or similar field, with 8+ 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 of 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.

Pay

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
Parental Leave
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

Benefits

• Generous Paid Time Off (PTO)
• Generous Holiday Schedule
• Relocation Assistance
• Professional and Educational Support Opportunities