Criticality Safety Engineer

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 or the equivalent combination of education and related experience.

Comprehensive knowledge of and experience working in a nuclear facility, nuclear reactor, chemical, high hazard, (e.g., explosive), radiological operations, or similarly complex or highly regulated facility.

Broad application of technical, analytical and decision-making skills and record of achievement in performing criticality safety evaluations or research.

Proficient with personal computers and radiation transport software (e.g., COG, MCNP, SCALE).

Experience preparing technical documents following appropriate protocols (e.g., criticality safety evaluations, safety basis calculations, design calculations, and drawings/sketches).

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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

We have an opening for a

Criticality Safety Engineer.

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.  This position is in the Nuclear Criticality Safety Division within the Environment, Safety, and Health (ES&H) Directorate.

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

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.