Core Design Engineer

Oklo; Santa Clara (CA); Hybrid; USD 140,000 - 190,000; Full time

Benefits offered by this job

Flexible time off

Equity

Bonuses

Competitive pay

401(k)

Health insurance

Job summary

Oklo Inc. is seeking a Core Design Engineer to join its engineering team in Santa Clara. The role focuses on designing performant and manufacturable reactor cores while balancing neutronic, thermal-hydraulic, material, mechanical, and economic considerations.

You will run multiphysics simulations, author design documentation, validate core requirements, and work with fabrication engineers to mature designs, with level determined by experience. Occasional travel to the Santa Clara HQ is required.

Qualifications

• Bachelor’s, Master’s, or PhD in nuclear engineering or a related field.
• Experience with core design from a multidisciplinary perspective.
• Experience with Python or C++ programming.
• Experience with neutronics analyses.
• Experience with thermal-hydraulic analysis.
• Experience with material analysis.

Responsibilities

• Travel to headquarters in Santa Clara, CA 2x per quarter for meetings or events.
• Translate stakeholder requirements into system functional requirements.
• Model core performance over time using multiphysics simulations.
• Document work with clear technical reports and writeups.
• Collaborate with cross-functional teams to define performance requirements and provide feedback to methods teams.

Skills

Nuclear engineering

Multiphysics simulations

Python

C++

Technical writing

Neutronics analyses

Education

Nuclear engineering degree (Bachelor/Master/PhD)

Tools

SERPENT

MCNP

SASSYS-1

DIF3D

REACTOR CODES

Job description

Thanks for your interest in Oklo! We are searching for a Core Design Engineer to join our engineering team.

Position Description

Core Design Engineers at Oklo are responsible for designing performant and manufacturable reactor cores which balance neutronic, thermal hydraulic, material, mechanical, and economic considerations. Work performed by Core Design Engineers includes executing multiphysics simulations to assess core performance, writing clear and thorough design documentation, performing analyses to validate and verify core requirements, and working closely with fabrication engineers to mature their designs.

Core design is an interdisciplinary field, we are looking for applicants who have a holistic understanding of reactor physics that lets them quickly ascertain how proposed design changes will impact core performance. Level will be determined based on applicant experience.

Specific responsibilities may include:

• Traveling to headquarters (Santa Clara, CA) 2x per calendar quarter for team meetings, company offsite, or other business gatherings
• Translating top-level stakeholder requirements into well-written system functional requirements
• Modeling core performance over time through multiphysics simulations and first principles approaches
• Documenting work using modern tools and techniques, and producing well-written technical reports
• Collaborating cross-functionally to define performance requirements, and providing technical feedback to methods development teams

Minimum Qualifications:

• Bachelors, Masters, or PhD in nuclear engineering or a related field
• Experience with core design from a multidisciplinary perspective
• Experience with object‑oriented programming language (e.g., Python, C++)
• Experience with neutronic analyses
• Experience with thermal hydraulic analysis
• Experience with material analysis

Bonus Qualifications:

• Familiarity with principles of fast reactor core design
• Experience with fuel cycle optimization
• Familiarity/experience with ternary fuel and ternary fuel cycles
• Experience with CI/CD computing environments
• Experience with Monte Carlo neutronics tools (e.g., SERPENT, MCNP, SCALE, etc.)
• Experience with deterministic neutronics tools (e.g., DIF3D, PERSENT, etc.)
• Experience with reactor systems codes (e.g., SAS4A/SASSYS‑1, SAM, RELAP, TRACE, GOTHIC, etc.)
• Experience with fuel analysis and fuel performance software (e.g., BISON, LIFE‑METAL, etc.)
• Fluency in Python

Who you are:

• Motivated: You are self‑motivated. You bring an enthusiasm to the team, and imbue a sense of passion that goes beyond clocking in and clocking out.
• A team‑player: Oklo genuinely is a team. We aren’t about taking credit for ourselves, and we aren’t about pushing blame to others.
• An excellent communicator: We need a person who is not only technically competent but also a clear and upbeat communicator.
• Creative: Being creative means that when things fall outside clear scopes or processes or problems arise without clear solutions, you are able to identify it as well as invent ways to solve a problem or fill a need without micromanagement.
• Detail‑oriented: This focus is a big part of excellence, consistency, and quality. Excellent grammar and spelling matter for both good communication as well as the image of the company that we put forward.

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. For the first two weeks of onboarding, employees are required to be in person at headquarters in Santa Clara, CA.

Benefits

• Flexible time off
• Equity
• Bonuses
• Competitive pay
• 401(k)
• Health insurance (with employer contribution)
• HSA
• FSA
• Flexible work hours
• Wellness credits
• Other benefits

This position may involve access to information subject to U.S. export control laws. Only applicants who meet the definition of a U.S. person under applicable laws may be eligible.

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.

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.