Reactor Core Thermal Fluids Engineer

Oklo is seeking a Thermal Fluids Engineer to join their Core Thermal-Hydraulics team, offering a significant opportunity to contribute to the development of advanced fission power plants. This role is ideal for engineers with a strong foundation in thermal-fluids analysis and a passion for nuclear energy innovation, providing a chance to work with cutting-edge modeling techniques and contribute to a mission-driven company focused on clean, reliable, and affordable energy. ### Position Description The Core Thermal-Hydraulics team at Oklo is responsible for analyzing fluid flow and heat transfer within a reactor core. The work includes engineering analyses of thermal-fluid dynamics, clear and thorough documentation of the analyses, as well as interfacing with design teams. An engineer on the team will contribute to the development, qualification, and validation of methods for modeling coolant flow within reactor cores using one-dimensional models, intermediate-fidelity subchannel models, and high-fidelity computational fluid dynamics models. ### Specific responsibilities may include: * Modeling core thermal-hydraulic behavior using: * Subchannel codes such as DASSH, MOOSE-Subchannel, or COBRA-TF * One-dimensional systems codes such as SAS4A/SASSYS-1 or RELAP * First principles approaches and in-house flow network models * 3-D computational fluid dynamics * Developing and documenting methods to analyze core thermal-hydraulic behavior at steady-state and during transients * Automation, verification, and validation of modeling and simulation tools in support of analyses * Collaborating cross-functionally to define design requirements, and providing technical feedback to quick-iterating design teams ### Minimum Qualifications * Bachelors, Masters, or PhD in a technical field, such as nuclear, mechanical, or aerospace engineering * Proficiency with thermal fluids (thermal-hydraulics) analysis methods and first principles * Able to write clear and concise documentation * Experience with: * Low-fidelity and intermediate-fidelity (e.g., porous body and correlation-based) models for heat transfer and fluid flow * Numerical methods and software development for heat transfer and fluid flow problems * Data processing (e.g., pre-processing, post-processing, scripting) ### Bonus Qualifications * Fluency with Python * Demonstrated success in qualification and validation of analyses * Experience with: * CI/CD computing environments * Reactor systems codes (RELAP or similar) * Subchannel analysis codes (COBRA-TF or similar) * High-fidelity computational fluid dynamics analysis ### Competencies We are looking for a Thermal Fluids Engineer that is: * Willing and able to learn quickly * Deeply skilled in analysis of heat transfer and fluid flow in confined geometries * Eager to work on a dynamic team, receive constructive feedback, and grow with us * Excited to think creatively, critically, and reflectively about the problems they are solving * Familiar with the importance of high-quality documentation ### About Oklo travel requirements: Oklo requires remote employees to travel to headquarters (Santa Clara, CA) twice a quarter annually, based on business or team needs, including attendance at team meetings, off-sites, and other company events or gatherings. Some travel to other sites is also required for this position. For the first two weeks of onboarding, employees are required to be in person at headquarters in Santa Clara, CA. ### About Oklo compensation: Salary: $80,000-$175,000 Oklo offers flexible time off, equity, competitive pay, 401k, health insurance, FSA, flexible work hours, and other benefits. We are looking to fill this position immediately! ### About Oklo Inc.: Oklo Inc. is developing fast fission power plants to deliver clean, reliable, and affordable energy at scale; establishing a domestic supply chain for critical radioisotopes; and advancing nuclear fuel recycling to convert nuclear waste into clean energy. Oklo was the first to receive a site use permit from the U.S. Department of Energy for a commercial advanced fission plant, was awarded fuel material from Idaho National Laboratory, and submitted the first custom combined license application for an advanced reactor to the U.S. Nuclear Regulatory Commission. Oklo is also developing advanced fuel recycling technologies in collaboration with the U.S. Department of Energy and U.S. National Laboratories. ### #CHOP: Oklo’s Values * **Collaboration**: We go further, together. We bring diverse perspectives, listen actively, and build trust through transparency and respect. We work across disciplines, sharing ownership to turn complex challenges into shared successes. * **Humility**: We are team players who act for the good of the company and for the world. We are focused on our mission, not personal recognition. * **Ownership**: We take pride in what we do and how we do it. We are proactive in finding solutions and see tasks through to completion. We are committed to delivering on our promises to provide clean, reliable, and affordable energy. * **Pathfinding**: We chart new ground where no path exists by approaching challenges with curiosity, courage, and creativity while navigating ambiguity. Candidates should be aware that employment may be contingent upon successful completion of a drug screening, and employees may be subject to drug testing at any time in accordance with company policy and applicable laws. ### Recruitment Fraud Disclaimer Oklo is aware of recent recruitment fraud attempts targeting job seekers. Please be cautious of anyone claiming to represent Oklo who does not contact you from an official Oklo email address. All legitimate communications from our recruiting team— including application updates, interview requests, and job offers — will come exclusively from an @oklo.com email. Oklo will never ask for sensitive personal information, payments, or account credentials during the hiring process. If you receive suspicious outreach or have concerns about the authenticity of any communication claiming to be from Oklo, please contact us through the official channels listed on our website.