Nuclear Criticality Safety Postdoctoral Research Staff

LLNL; Livermore (CA); Hybrid; USD 115,000 - 156,000; Full time

Job summary

Lawrence Livermore National Laboratory (LLNL) seeks a Postdoctoral Researcher in Nuclear Criticality Safety in the Nuclear Criticality Safety Division. The role offers a hybrid schedule and requires U.S.

citizenship with DOE Q clearance. You will design, model, and analyze laboratory critical and subcritical experiments; develop radiation measurement instrumentation; oversee equipment fabrication; and help prepare safety reviews and publications.

Qualifications

• PhD in Nuclear Engineering, Physics, or a related field required.
• DOE Q clearance or ability to obtain; U.S. citizenship required.
• Experience with radiation transport methods and computational physics.

Responsibilities

• Collaborate in design, modeling, and analysis of lab critical and subcritical experiments.
• Develop radiation measurement instrumentation and measure radiation fields.
• Design and oversee fabrication of equipment as required.
• Develop experimental procedures and guide them through safety and reviews.
• Perform criticality safety evaluations of laboratory work.
• Publish results in peer‑reviewed journals and present at conferences.
• Operate independently and in multidisciplinary teams.

Skills

Python

FORTRAN

C++

Radiation transport

Independent work

Communication

Multidisciplinary teamwork

Education

PhD in Nuclear Engineering, Physics, or related field

Tools

MCNP

SCALE

GEANT

OpenMC

Serpent

Job description

Nuclear Criticality Safety Postdoctoral Research Staff

• Full-time
• Organization: ESH and Quality
• Category: Environmental, Safety & Health
• Employee Referral Bonus: Not applicable
• Job Code 1: PDS.1 Post-Dr Research Staff 1
• Pre-Employment Drug Test: Required for external applicant(s) selected for this position (includes testing for use of marijuana)
• Pre-Placement Medical Exam: Not applicable
• Security Clearance: Anticipated DOE Q clearance (requires U.S. citizenship and a federal background investigation)
• Position Type: Post Doctoral

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 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.

• 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.

#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!
• Flexible schedules (*depending on project needs)

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 useand/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.

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.

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