TITLE: System Transients Thermal Hydraulics Code Developer 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 Thermal Hydraulics Code Developer Reporting to the Manager of Code and Methods Development, the System Transients T/H Code Developer is responsible for the development of RELAP5-3D code for both thermal-hydraulics plant-wide and component level transient analysis with application to the TerraPower sodium-cooled reactor program following TerraPower NQA-1 procedures. A successful candidate should possess a strong fundamental thermal hydraulic and code development background. Responsibilities Develop RELAP5 features for use in the modeling of next generation nuclear reactors. Debug legacy FORTRAN source code. Perform code reviews under NQA-1 umbrella. Perform code benchmarking and validation analyses to support code qualification and methodology development using RELAP5-3D following the EMDAP process (NuReg 1.203). Perform calculations using first principles of heat transfer, fluid dynamics, and thermodynamics to support and validate code modifications. Assist in maintaining Py53D automation tool to automate pre-processing, submission and post-processing of RELAP5 calculations. 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 development or modification (3+ years). Experience with software development. (python/FORTRAN preferred but not required) Familiarity with code V&V and associated regulatory requirements. Experience with nuclear power plant design or operations a plus. Experience in working in multi-disciplinary engineering teams to address engineering challenges. Experience with cloud based high performance computing platforms such as Azure, AWS is a plus. Experience with advanced reactor technologies, such as sodium fast reactors is a plus. Strong technical writing skills. Effective communication skills. The successful candidate will possess a high degree of trust and integrity, communicate openly and display respect and a desire to foster teamwork. Job Functions Job Functions are physical actions and/or working conditions associated with the