Senior Nuclear Criticality Safety Engineer

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

Position Description

A Senior Nuclear Criticality Safety Engineer at Oklo is responsible for performing criticality safety evaluations, developing the nuclear criticality safety basis, and architecting the nuclear criticality safety program for a first-of-a-kind used nuclear fuel recycling facility.

Specific responsibilities may include:

• Identifying and evaluating nuclear criticality safety (NCS) hazards for fuel cycle facilities
• Performing criticality safety evaluations (CSEs) to demonstrate subcriticality under normal and credible abnormal conditions
• Developing the criticality code validation report
• Demonstrating compliance with the double-contingency principle
• Documenting criticality hazard analyses, CSEs, and supporting technical information
• Evaluating and implementing controlled parameters for the NCS program
• Developing the criticality accident alarm system and inadvertent criticality emergency response plan
• Supporting safety basis development and licensing efforts
• Developing and administering the NCS program, methodologies, and management measures

Minimum Qualifications:

• Bachelors, Masters, or PhD in nuclear engineering, chemical engineering, or chemistry, or related field
• Minimum 5+ years experience performing CSEs as a part of a nuclear facility’s safety basis

Bonus Qualifications:

• Knowledge of used nuclear fuel recycling technologies
• 10+ years of experience performing criticality safety evaluations for an NRC licensed fuel cycle facility

Competencies

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

• Knowledge of nuclear science, physics of criticality, and chemistry
• Knowledge of nuclear fuel cycle processes and nuclear fuel cycle facility accident scenarios
• Proficient with Attila4MC, MCNP, SCALE, and/or Serpent codes and modules
• Familiarity with critical experiments and their purpose
• Knowledge of criticality-specific codes, standards, regulatory requirements, and industry practices for nuclear fuel cycle facilities
• Familiarity with NUREG-1513, NUREG-1520, NUREG/CR-6410, NUREG/CR-6698, NUREG/CR-7311, and NRC RG 3.71
• Passionate about clean energy and making advanced fission a reality
• Knowledgeable about structural design, analysis, and construction
• Eager to work on a dynamic team, receive constructive feedback, and grow with us
• Willing to think differently and learn quickly
• Comfortable in a fast-paced, highly iterative startup environment
• Excited to think creatively, critically, and reflectively about the problems they are solving, while not leaning only on what has been done before 
• An excellent writer who can communicate technical concepts in modern active voice

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: $135,000-$175,000

Oklo offers flexible time off, equity, competitive pay, 401k, health insurance, FSA, flexible work hours, 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 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.