Principal Engineer, Safety Methods

TerraPower LLC.•Bellevue, WA

9d•$140,021 - $181,845•Onsite

About The Position

This role supports the development, enhancement, and deployment of plant‑scale thermal‑hydraulic analysis methods and models for the Natrium reactor. Reporting to the Manager, Plant Thermal Hydraulics Methods, the principal engineer supports the creation, improvement and qualification of advanced system-level modeling approaches that enable accurate, robust prediction of plant behavior across operational and transient scenarios. The position requires expertise in system‑level thermal‑hydraulics, thermal‑fluids behavior, computational methods, and scaling analysis supporting benchmarking computational models against experimental data.

Requirements

Degree in Mechanical, Nuclear, Chemical Engineering, or similar field, with 8 plus 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 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.
Strong analytical thinking, clear technical communication, and the ability to manage multiple validation tasks in parallel.

Nice To Haves

Experience with SQA and NQA‑1 quality assurance practices for modeling workflows is highly preferred.

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.