Senior Engineer, Plant Thermal Hydraulic Methods

Job Title: Senior Engineer, Plant Thermal Hydraulic Methods
Location: Bellevue, WA
Type: Contract
Compensation: From $56.00 to $95.00 per hour
Contractor Work Model: Remote – offsite

Overview
System One is seeking a Senior Engineer, Plant Thermal Hydraulic Methods to support our client on a contract basis.

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 method 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 analysis frameworks.
• Identify modeling gaps and support method enhancement using and sensitivity studies.
• Develop automated workflows and tools for model setup, execution, post-processing, and repeatable method application.
• Document modeling methodologies, assumptions, method applicability, and numerical performance for design processes 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 SQA and NQA 1 modeling practices, ensuring traceability, configuration control, and reproducibility of methods.

• Degree in Mechanical, Nuclear, Chemical Engineering, or similar fields.
• 6+ years of experience in system-level thermal hydraulic modeling and method development for nuclear or complex energy systems.
• Demonstrated experience in 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 scientific programming and workflow automation (e.g., Python, MATLAB).
• Familiarity with NQA 1 quality assurance for modeling workflows, including documented methodologies, configuration control, and model traceability.
• Strong analytical thinking, clear technical communication, and the ability to support multiple method development efforts in parallel.
• Strong communication skills; high degree of trust and integrity, open communication, respect, and teamwork orientation.

System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.

System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, Marital status, or any other characteristic protected by applicable federal, state, or local law.

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