Senior Engineer, Plant Thermal Hydraulics Methods

Overview

System One is seeking a Senior Engineer, Plant Thermal Hydraulics Methods contractor to support the design and licensing of a client’s demonstration reactor. The role primarily involves developing methods to perform Licensing Basis Events (LBE) analyses and may also contribute subject‑matter expertise to other projects under development.

Responsibilities

• Develop plant‑scale 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 correlations (e.g., heat transfer, pressure drop, mixing, component‑level physics) into existing analysis frameworks.
• Identify modeling gaps and support method enhancement using 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 client’s SQA and NQA‑1 modeling practices, ensuring traceability, configuration control, and reproducibility of methods.

Requirements

• Bachelor’s degree in Mechanical, Nuclear, Chemical Engineering, or a related field.
• 5+ years of experience in system‑level thermal hydraulic modeling and method development for nuclear or complex energy systems.
• Proven experience developing or improving analysis methods, including numerical scheme development, closure model formulation, and stability/accuracy optimization.
• Experience performing system‑level thermal hydraulic analyses using tools such as RELAP5‑3D, GOTHIC, SAS, or equivalent, with ability to extend or tailor modeling approaches.
• 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 to support method development priorities.
• Familiarity with scientific programming and workflow automation (e.g., Python, MATLAB).
• Knowledge of NQA‑1 quality assurance for modeling workflows, including documented methodologies, configuration control, and model traceability.
• Strong analytical thinking, clear technical communication, and ability to manage multiple method‑development efforts in parallel.

Benefits

• Health, dental, and vision insurance options.
• Spending accounts and life insurance.
• Voluntary benefit plans.
• Participation in a 401(k) retirement plan.

Pay

Compensation range: $52.00 – $85.00 per hour.

Schedule

Fully remote (offsite) work model, 40‑hour work week with paid holidays and PTO.