Principal Engineer, Safety Methods

TerraPower LLC.•Bellevue, WA

12d•$140,021 - $181,845

About The Position

TerraPower is seeking a Principal Engineer, Safety Methods to support 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, this principal engineer will help create, improve, and qualify advanced system-level modeling approaches for accurately and robustly predicting plant behavior across operational and transient scenarios. The role requires expertise in system-level thermal hydraulics, thermal-fluid behavior, computational methods, and scaling analysis, including benchmarking computational models against experimental data. The engineer will contribute to verification, validation, and uncertainty quantification; develop validation strategies and test requirements; document analyses for design and regulatory processes; and collaborate across plant design, safety analysis, licensing, and experimental testing. The position also includes mentoring junior engineers and maintaining quality practices and traceability for modeling work. This is a full-time position in Washington State. Travel is 0–10%.

Requirements

Degree in Mechanical, Nuclear, Chemical Engineering, or a similar field.
At least 8 years of experience in 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 with experimental thermal-hydraulic data, including data analysis, uncertainty evaluation, and comparison against system-level predictions.
Proficiency with system analysis tools such as RELAP5-3D, TRACE, SAS, or equivalent, applied to plant-scale transient and steady-state evaluations.
Strong foundation in thermal-fluid and reactor-system behavior relevant to advanced reactor designs.
Experience performing scaling analysis to translate test-scale phenomena, including applying similarity criteria and qualifying the impact of scaling distortion.
Experience developing validation strategies, defining data needs, and coordinating with experimental programs.
Strong analytical thinking, clear technical communication, and ability to manage multiple validation tasks in parallel.
Meet the applicable education and experience criteria under ANSI/ANS 3.1, including relevant nuclear industry experience where required; data will be verified during hiring.

Nice To Haves

Experience with SQA and NQA-1 quality assurance practices for modeling workflows.

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 assess the applicability of test data to reference system conditions, including similarity criteria and scaling distortion.
Interpret experimental data from separate-effects and integral test facilities to support model validation and close technical gaps.
Define validation needs, develop test requirements, and collaborate with test engineering teams to align model gaps with experimental programs.
Document V&V methodologies, model assumptions, validation results, and uncertainty analyses for internal design processes and regulatory submittals.
Collaborate with multidisciplinary teams supporting plant design, safety analysis, and licensing workflows.
Apply and improve TerraPower’s SQA and NQA-1 modeling quality practices, ensuring traceability and configuration control of analysis inputs, models, and results.
Mentor junior engineers in system modeling, validation methodologies, and code-assessment best practices.