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Nuclear Criticality Safety Postdoctoral Research Staff

Lawrence Livermore National Laboratory
tuition reimbursement, 401(k), relocation assistance, remote work
United States, California, Livermore
Sep 09, 2026
Company Description

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.


Job Description

We have an opening for a Postdoctoral Researcher with experience in one or more of the following areas: nuclear physics; nuclear engineering; radiation transport; Multiphysics simulation. We are seeking a creative and flexible individuals who meets the scientific requirements and whose skills are aligned with the research mission of the National Nuclear Criticality Safety Program. This position will require interaction with professional colleagues inside and outside of the Laboratory and is located in the Nuclear Criticality Safety Division within the Environment, Safety and Health Directorate.

This position offers a hybrid schedule, blending in-person and virtual presence. The ability to work from home one or more days per week.

You will

  • Collaborate in the design, modeling, and analysis of laboratory critical and subcritical experiments.
  • Collaborate in the development of radiation measurement instrumentation and measurement of radiation fields.
  • Design and oversee fabrication of equipment as required.
  • Develop experimental procedures as required and guide them through safety and management reviews.
  • Assist in performing criticality safety evaluations of laboratory work.
  • Publish research results in peer-reviewed scientific or technical journals and present results at external conferences, seminars, and/or technical meetings.
  • Perform other duties as assigned.

Qualifications
  • Ability to secure and maintain a U.S. DOE Q-level security clearance which requires U.S. citizenship.
  • PhD in Nuclear Engineering, Physics, or related field.
  • Experience with radiation transport methods, such as MCNP, SCALE, GEANT, COG, Serpent, OpenMC etc.
  • Experience in computational physics and working knowledge of one or more programming languages (Python, FORTRAN, C++, etc).
  • Demonstrated proficient verbal and written communication skills necessary to author technical and scientific reports, proposals, publications and deliver scientific presentations.
  • Ability to work independently as well as in multidisciplinary research teams.
  • Ability to provide in-depth analyses and develop unique technical solutions.

Qualifications We Desire

  • Active DOE Qclearance.

Pay Range

$135,768 Annually

This is the lowest to highest salary we in good faith believe we would pay for this role at the time of this posting; pay will not be below any applicable local minimum wage. 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.


Additional Information

#LI-Onsite

Position Information

This is a Postdoctoral appointment with the possibility of extension to a maximum of three years, open to those who have been awarded a PhD at time of hire date.

Why Lawrence Livermore National Laboratory?

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

Security Clearance

This position requires a Department of Energy (DOE) Q-level clearance.If you are selected, wewill initiate a Federal background investigation to determine if youmeet 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 useand/or possession ofmobile devices in Limited Areas. Depending on your job duties, you may be required to work in a Limited Area whereyou are not permitted to have a personal and/or laboratory mobile devicein your possession. This includes, but not limited to cell phones, tablets, fitness devices, wireless headphones, and other Bluetooth/wireless enabled devices.

Ifyou useamedical device, whichpairs with a mobile device,you must still follow the rules concerningthe mobile device in individual sections within Limited Areas. Sensitive Compartmented Information Facilities requireseparate 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.

CaliforniaPrivacy Notice

The California Consumer Privacy Act (CCPA) grants privacy rights to all California residents. The law also entitlesjob 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.

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