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Nuclear Criticality Safety Engineer Jobs (NOW HIRING)

Pae

Criticality Safety Engineer

Aiken, SC · On-site

We are currently seeking a Nuclear Criticality Safety Engineer to support our AIKEN, SC office out at the Savannah River Site (SRS). The Engineer will provide engineering support for U.S. Department ...

Amentum

Criticality Safety Engineer

Aiken, SC · On-site

We are currently seeking a Nuclear Criticality Safety Engineer to support our AIKEN, SC office out at the Savannah River Site (SRS). The Engineer will provide engineering support for U.S. Department ...

Pae

Criticality Safety Engineer

Oak Ridge, TN · On-site

The Engineer will provide engineering support for U.S. Department of Energy (DOE) facilities and ... Candidates will obtain site specific Nuclear Criticality Safety (NCS) Analyst Qualification to ...

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Nuclear Criticality Safety Engineer information

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How much do nuclear criticality safety engineer jobs pay per year?

As of Jun 17, 2026, the average yearly pay for nuclear criticality safety engineer in the United States is $154,474.00, according to ZipRecruiter salary data. Most workers in this role earn between $146,000.00 and $161,000.00 per year, depending on experience, location, and employer.

What does a Nuclear Criticality Safety Engineer do?

A Nuclear Criticality Safety Engineer is responsible for ensuring that nuclear materials are handled, stored, and processed in a manner that prevents unintended nuclear chain reactions, known as criticality accidents. They analyze facility designs, operating procedures, and accident scenarios to assess risks and implement safety controls. Their work involves developing safety evaluations, performing calculations, and providing guidance on safe practices. This role is crucial in nuclear power plants, research labs, and facilities that handle fissile materials to protect workers, the public, and the environment.

What Does a Nuclear Criticality Safety Engineer Do?

As a nuclear criticality safety engineer, your responsibilities include conducting research and evaluating methods of transportation, handling, and storage of nuclear fuel to prevent an accident such as a nuclear reaction. You study and review research on nuclear fuel characteristics and calculation documents, as well as conduct an analysis of fuel transfer and storage plans provided by nuclear plants. Other duties include identifying potential hazards and areas in a nuclear plant that may be violating regulations, designing new methods for transport or storage, preparing proposal reports describing your recommendations, and submitting these reports to the government review board.

How does a Nuclear Criticality Safety Engineer typically collaborate with other professionals on-site?

Nuclear Criticality Safety Engineers work closely with a multidisciplinary team, including reactor operators, health physicists, process engineers, and regulatory compliance staff. They participate in safety reviews, provide technical guidance during facility modifications, and help develop and implement criticality safety procedures. Regular communication and teamwork are essential, as these engineers must ensure all stakeholders understand and follow safety protocols to prevent criticality accidents. Collaboration often includes attending interdepartmental meetings, conducting training sessions, and performing joint facility walkthroughs.

What is the difference between Nuclear Criticality Safety Engineer vs Nuclear Safety Engineer?

AspectNuclear Criticality Safety EngineerNuclear Safety Engineer
CertificationsOften requires certifications like ANSI/ANS-8 or equivalentMay require general nuclear safety or engineering certifications
Work EnvironmentFocuses on criticality safety in nuclear facilities and operationsEncompasses broader nuclear safety aspects including radiation protection and accident prevention
Industry UsagePrimarily in nuclear fuel handling, processing, and reactor operationsAcross nuclear power plants, research reactors, and regulatory agencies

The Nuclear Criticality Safety Engineer specializes in preventing nuclear chain reactions in fissile materials, ensuring safe handling and storage. In contrast, the Nuclear Safety Engineer has a broader role, addressing overall safety protocols, radiation protection, and accident prevention in nuclear facilities. While both roles require a strong understanding of nuclear principles, the Criticality Safety Engineer focuses specifically on criticality risks, making their expertise more specialized within the nuclear safety field.

What are the key skills and qualifications needed to thrive as a Nuclear Criticality Safety Engineer, and why are they important?

To thrive as a Nuclear Criticality Safety Engineer, you need a strong background in nuclear engineering, physics, or a related field, often supported by a relevant bachelor's or master's degree. Familiarity with criticality safety codes (such as SCALE or MCNP), regulatory compliance standards, and radiation monitoring systems is essential. Attention to detail, strong problem-solving abilities, and effective communication skills are crucial for risk assessment and collaboration with multidisciplinary teams. These skills ensure the safe handling and processing of nuclear materials, preventing criticality accidents and ensuring regulatory compliance.
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Nuclear Criticality Safety Engineer jobs near you
Infographic showing various Nuclear Criticality Safety Engineer job openings in the United States as of June 2026, with employment types broken down into 100% Full Time. Highlights an 92% In-person, and 8% Remote job distribution, with an average salary of $154,474 per year, or $74.3 per hour.
Senior Nuclear Criticality Safety Engineer

Senior Nuclear Criticality Safety Engineer

Oklo

Santa Clara, CA

$135K - $175K/yr

Other

Medical, Retirement

Posted 27 days ago

Job description

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.

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