TITLE: System Transients Methodology Engineer (Multi-level) LOCATION: Bellevue, WA, USA 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. As a result, the company's activities in the fields of nuclear energy and related sciences are yielding significant innovations in the safety and economics of nuclear power, hybrid energy and medical applications - all for significant human health 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. System Transients Methodology Engineer (Multi-level) Reporting to the Manager of Code and Methods Development, the System Transients Methodology Engineer is responsible for the development of methodology reports using RELAP5-3D code for both thermal-hydraulics plant-wide and component level transient analysis with application to the TerraPower sodium-cooled reactor program following the EMDAP process under TerraPower NQA-1 procedures. In addition, the successful applicant should be capable of assisting in the development and maintenance of tools used to perform RELAP5 calculations and postprocess results (this may include RELAP code development). Responsibilities Perform code benchmarking and validation analyses to support code qualification and methodology development using RELAP5-3D following the EMDAP process (NuReg 1.203). Develop methodology studies demonstrating foundational analysis of the reactor to aid in licensing of Natrium. Develop RELAP5-3D models for steady state and transient one-dimensional network hydraulic analyses. Perform calculations using first principles of heat transfer, fluid dynamics, and thermodynamics to support and validate analysis results. Perform analysis of plant wide transients for evaluation of operation narratives and design solutions. Support selection, procurement and qualification of applicable legacy test data. Assist in maintaining either Py53D automation tool to automate RELAP5 calculation submission or assist with RELAP5-3D base code development (FORTRAN). Key Qualifications and Skills B.S. (+ 5 years), M.S. (+3 years), or PhD (+ 1 year) in nuclear, mechanical, or another related engineering/scientific field. Strong thermal-hydraulic analytical skills with one dimensional hydraulic network analysis, system codes experience and transient analysis. Knowledgeable in nuclear systems thermal-hydraulic, reactor dynamics, and transient phenomena. Significant Experience with RELAP5-3D code (3+ years). Experience with software development. (python/FORTRAN preferred but not required) Familiarity with code V&V and associated regulatory requirements. Experience with scaling analysis as it pertains to RG 1.203 is a plus. Experience with nuclear power plant design or operations a plus. Experience in working in multi-disciplinary engineering teams to address engineering challenges. Strong technical writing