Thanks for your interest in Oklo! We are searching for a Criticality Analysis & Nuclear Safety Engineer to join our engineering team.

Position Description

As a Criticality Analysis & Nuclear Safety Engineer on Oklo's Fuel Fabrication team, you'll be responsible for developing and maintaining the nuclear criticality safety basis and nuclear safety analyses supporting the design, licensing, construction, commissioning, and operation of advanced nuclear fuel fabrication facilities. You'll perform computational analyses, establish engineered and administrative controls for fissile material operations, and work closely with process, mechanical, operations, licensing, and quality teams to ensure facility designs meet rigorous nuclear safety requirements.

This is a highly cross-functional role where technical excellence and a collaborative mindset are equally valued.

Specific responsibilities may include:

• Develop Criticality Safety Evaluations (CSEs) and supporting calculations.

• Perform criticality analyses using MCNP, SCALE, SERPENT, or equivalent software.

• Develop nuclear safety analyses including hazard evaluations and accident analyses.

• Establish fissile material limits, mass limits, geometry controls, moderation controls, and administrative controls.

• Support facility design reviews to ensure criticality-safe equipment layouts and process designs.

• Work with process engineers developing HALEU, plutonium, and uranium metal processes.

• Support NRC licensing documentation and responses to regulatory requests.

• Participate in HAZOPs, What-If analyses, FMEAs, and design reviews.

• Develop criticality alarm system requirements and safety basis documentation.

• Support startup testing, operational readiness reviews, and commissioning.

• Investigate abnormal conditions and recommend corrective actions.

• Maintain compliance with ANSI/ANS-8 standards and applicable NRC/DOE requirements

Minimum Qualifications:

• Bachelor's or higher degree in Nuclear Engineering or closely related discipline.

• Experience performing nuclear criticality or safety analyses.

• Knowledge of neutron transport methods and computational modeling.

• Understanding of NRC or DOE nuclear safety requirements.

• Strong technical writing and communication skills.

• Ability to work effectively within multidisciplinary engineering teams.

Bonus Qualifications:

• Graduate degree in Nuclear Engineering.

• Experience supporting HALEU, plutonium, or uranium fuel fabrication facilities.

• Experience preparing NRC licensing analyses.

• Knowledge of DOE-STD-3007 and nuclear safety basis methodologies.

• Experience with HAZOPs, accident analysis, or probabilistic risk assessment.

• Familiarity with NQA-1 quality programs.

Competencies

We are looking for a Criticality Analysis & Nuclear Safety Engineer that is:

• Strong understanding of neutron physics and criticality safety principles.

• Experience applying ANSI/ANS-8 standards.

• Proficient with MCNP, SCALE, SERPENT, or equivalent modeling software.

• Able to evaluate complex nuclear process systems and identify credible accident scenarios.

• Comfortable working across engineering, operations, licensing, and quality organizations.

• Excellent technical writing and presentation skills.

• Passionate about clean energy and advanced fission.

• Comfortable in a fast-paced startup environment.

• Creative, detail-oriented, and committed to nuclear safety culture.

Experience Level

• 3–10+ years of experience performing nuclear criticality safety or nuclear safety analyses in fuel cycle, reactor, DOE, national laboratory, or other highly regulated nuclear environments.

Who you are:

A startup person: You aren't driven by titles or hierarchy, and prefer efficiency to excess process. You don't need or expect to have a lot of guidance but you enjoy working in a fast-paced team. If you prefer the culture and feel of a large organization, that is great, but you likely won’t enjoy working with us! There is plenty of important work and plenty of good opportunities with organizations like that.

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. This isn’t about a fake or arbitrary “pieces of flair” mentality or lack of work-life balance! It is about being a part of the vision and feeling a part of reaching team goals.

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. We do incredible things because we work as a team.

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. The successful person in this job will not only be creative, but also enjoy being creative and solving open-ended problems which may change day-by-day.

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.

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

About Oklo compensation:

Salary: $120,000-$190,000

Oklo offers flexible time off, equity, bonuses, competitive pay, 401(k), health insurance (with employer contribution), HSA, FSA, flexible work hours, wellness credits, and 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 ValuesCollaboration: 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.