Reactor Core Thermal Fluids Engineer Santa Clara, CA or remote

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. A 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.

• Modeling core thermal‑hydraulic behavior using subchannel codes such as DASSH, MOOSE‑Subchannel, or COBRA‑TF
• Use one‑dimensional systems codes such as SAS4A/SASSYS‑1 or RELAP
• Apply first‑principles approaches and in‑house flow network models
• Develop and document 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
• Collaborate cross‑functionally to define design requirements, and provide technical feedback to rapid‑iterating design teams

• 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 (pre‑processing, post‑processing, scripting)

• 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

• 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

Remote employees are required to travel to headquarters in Santa Clara, CA twice a quarter annually and attend company events and meetings. Some travel to other sites is also required. The first two weeks of onboarding require in‑person presence at headquarters.

Oklo offers flexible time off, equity, competitive pay, 401(k), health insurance, FSA, flexible work hours, and other benefits.