Join us and make YOUR mark on the World!

Lawrence Livermore National Laboratory (LLNL) has turned bold ideas into world-changing impact advancing science and technology to strengthen U.S. security and promote global stability. 

Our mission spans four critical national security areas nuclear deterrence, threat preparedness, energy security, and multi-domain defense empowering teams to take on the toughest challenges of today and tomorrow. With a culture built on innovation and operational excellence, LLNL is a place where your expertise can make a real impact.

We have an opening for an Associate Criticality Safety Engineer within the Environment, Safety, and Health (ES&H) Directorate. You will contribute to the design, development, and testing of nuclear equipment and systems for Lawrence Livermore National Laboratory (LLNL) operations with fissionable materials.  You will also contribute to projects and task assigned to LLNL supporting the Department of Energy (DOE) Nuclear Criticality Safety Program (NCSP). This position is in the Nuclear Criticality Safety Division (NCSD).

This position will be filled at either level based on knowledge and related experience as assessed by the hiring team. Additional job responsibilities (outlined below) will be assigned if hired at the higher level. 

This position requires full-time on-site presence due to the nature of the work.

You will 

• Assist with criticality safety evaluations in conformance with DOE-STD-3007 and LLNL administrative procedures and support the review of new or proposed changes to existing equipment or operating procedures.
• Perform walk-through inspections and assist with basic annual reviews of operations and work authorization/work control documents and support the review of safety procedures and documents for consistency with criticality safety evaluations and adequate implementation of criticality safety controls.
• Perform technical/scientific assignments of limited complexity using established methods and procedures under general direction, and provide technical support to engineers, scientists, and facility staff as a member of a team in scientific research and development projects and/or ongoing operations.
• Gather, organize, and assist in analyzing data and information in support of the work activities, and help prepare documents, calculations, recommendations, corrective action documentation, designs, or related technical work products.
• Contribute to solutions for routine or limited-complexity problems using standard techniques and established practices, supporting project and organizational goals.
• Travel to the Nevada National Security Sites as needed.
• Conduct Fundamentals of Criticality Safety training courses.
• Perform other duties as assigned.

Additional job responsibilities, at the SES.2 level 

• Serve as the principal investigator or technical lead for critical or sub-critical benchmark experiments.
• Present and disseminate research results at scientific conferences and in peer-reviewed publications, in both open and classified environments, internal and external to LLNL.
• Positively represent the program and laboratory demonstrating advanced verbal and written skills. Responsibilities may also include interacting with external stakeholders, both at NNSA and across the broader interagency, via offsite assignments.

• Ability to secure and maintain a U.S. DOE Q-level security clearance which requires U.S. citizenship.
• Bachelor’s Degree in Nuclear Engineering, Physics, or closely related scientific discipline (e.g., mechanical/systems engineering, nuclear physics, particle physics, radiochemistry) or equivalent combination of education and prior relevant experience.
• Fundamental knowledge of and some academic, internship, research, or work experience in a nuclear facility, nuclear reactor, chemical, high hazard, radiological operation, or similarly regulated technical environment.
• Ability to apply fundamental technical, analytical, and problem-solving skills to assigned work using established methods and procedures.
• Familiarity with personal computers and exposure to radiation transport software such as COG, MCNP, GEANT, or SCALE is desirable.
• Ability to assist with preparing technical documents and calculations following established protocols and guidance.
• Basic familiarity with DOE orders, national consensus standards, and engineering practices is desirable.
• Proficient verbal and written communication and interpersonal skills to work effectively in a collaborative team environment.
• Ability to document and explain assigned technical or operational work results to supervisors, project leads, and team members.
• Ability to reprioritize and change programmatic direction depending on emergent requests and in collaboration with a variety of multidisciplinary teams.

Additional qualifications at the SES.2 level 

• Experience handling or performing experiments with fissile material.
• Experience with computer-based design and analysis of experiments with knowledge of modeling in particle transport codes such as COG, MCNP, GEANT, or SCALE.
• Experience conducting training and independently giving guidance to programs.

Qualifications We Desire

• Master’s Degree in Nuclear Engineering, Physics, or closely related scientific discipline or equivalent combination of education and prior relevant experience.
• Experience in criticality safety including preparing criticality safety evaluations and implementation of criticality safety controls.
• Knowledge of LLNL’s policies, procedures, and practices.
• Knowledge of and/or experience with DOE STD-3007 and ANSI/ANS-8 Series Consensus Standards.

Pay Range: $121,830 - $185,544 Annually

$121,830 - $154,500 Annually at the SES.1 Level

$146,340 - $185,544 Annually at the SES.2 Level

This is the lowest to highest salary range in good faith we would pay for this role at the time of this posting. An employee’s position within the salary range will be based on several factors including, but not limited to, specific competencies, relevant education, qualifications, certifications, experience, skills, seniority, geographic location, performance, and business or organizational needs.

#LI-Onsite

Position Information

This is a Career Indefinite position, open to Lab employees and external candidates.

Why Lawrence Livermore National Laboratory?

• Included in 2026 Best Places to Work by Glassdoor!
• Flexible Benefits Package
• 401(k)
• Relocation Assistance
• Education Reimbursement Program
• Flexible schedules (*depending on project needs)
• Our values - visit https://www.llnl.gov/inclusion/our-values

Security Clearance

This position requires a Department of Energy (DOE) Q-level clearance.  If you are selected, we will initiate a Federal background investigation to determine if you meet eligibility requirements for access to classified information or matter. Also, all L or Q cleared employees are subject to random drug testing.  Q-level clearance requires U.S. citizenship. 

Pre-Employment Drug Test

External applicant(s) selected for this position must pass a post-offer, pre-employment drug test. This includes testing for use of marijuana as Federal Law applies to us as a Federal Contractor.

Wireless and Medical Devices

Per the Department of Energy (DOE), Lawrence Livermore National Laboratory must meet certain restrictions with the use and/or possession of mobile devices in Limited Areas. Depending on your job duties, you may be required to work in a Limited Area where you are not permitted to have a personal and/or laboratory mobile device in your possession.  This includes, but not limited to cell phones, tablets, fitness devices, wireless headphones, and other Bluetooth/wireless enabled devices.  

If you use a medical device, which pairs with a mobile device, you must still follow the rules concerning the mobile device in individual sections within Limited Areas.  Sensitive Compartmented Information Facilities require separate approval. Hearing aids without wireless capabilities or wireless that has been disabled are allowed in Limited Areas, Secure Space and Transit/Buffer Space within buildings.

How to identify fake job advertisements

Please be aware of recruitment scams where people or entities are misusing the name of Lawrence Livermore National Laboratory (LLNL) to post fake job advertisements. LLNL never extends an offer without a personal interview and will never charge a fee for joining our company. All current job openings are displayed on the Career Page under “Find Your Job” of our website. If you have encountered a job posting or have been approached with a job offer that you suspect may be fraudulent, we strongly recommend you do not respond.

To learn more about recruitment scams: https://www.llnl.gov/sites/www/files/2023-05/LLNL-Job-Fraud-Statement-Updated-4.26.23.pdf

Equal Employment Opportunity

We are an equal opportunity employer that is committed to providing all with a work environment free of discrimination and harassment. All qualified applicants will receive consideration for employment without regard to race, color, religion, marital status, national origin, ancestry, sex, sexual orientation, gender identity, disability, medical condition, pregnancy, protected veteran status, age, citizenship, or any other characteristic protected by applicable laws.

Reasonable Accommodation

Our goal is to create an accessible and inclusive experience for all candidates applying and interviewing at the Laboratory.  If you need a reasonable accommodation during the application or the recruiting process, please use our online form to submit a request. 

California Privacy Notice

The California Consumer Privacy Act (CCPA) grants privacy rights to all California residents. The law also entitles job applicants, employees, and non-employee workers to be notified of what personal information LLNL collects and for what purpose. The Employee Privacy Notice can be accessed here.