Reactor Core Thermal Fluids Engineer

Thanks for your interest in Oklo! We are searching for a Thermal Fluids Engineer to join our Core Thermal‑Hydraulics team.

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, and 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; one‑dimensional systems codes such as SAS4A/SASSYS‑1 or RELAP; first principles approaches and in‑house flow network models; and 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.

• 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; and data processing (e.g., 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.

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.

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!