TerraPower is a nuclear technology company based in Bellevue, Washington. At its core, the company is working to raise living standards globally through a more affordable, secure, and environmentally friendly form of nuclear energy along with innovations in medical isotopes to improve human health. In 2006, TerraPower originated with Bill Gates and a group of like-minded visionaries who evaluated the fundamental challenges to raising living standards around the world.

They recognized energy access was crucial to the health and economic well-being of communities and decided that the private sector needed to take action and create energy sources that would advance global energy deployment. TerraPower’s mission is to be a world leader in new nuclear technologies, while developing innovators and future leaders in the nuclear field.

Benefits

” TerraPower is seeking to hire highly motivated and forward-thinking professionals who are interested in focusing on advanced nuclear reactor research and development and influencing change within the nuclear power landscape and bringing forward the critical production of medical isotopes. TerraPower is an Equal Opportunity Employer. We do not discriminate in hiring on the basis of sex, gender identity, sexual orientation, race, color, religious creed, national origin, physical or mental disability, protected Veteran status, or any other characteristic protected by federal, state, or local law.

Principal Safety Methods Engineer 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.

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.

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 plus years in the field of system‑level thermal‑hydraulic analysis and code assessment for nuclear or complex energy systems.