Criticality Safety Engineer

About the role

You will ensure fissile material can never achieve an uncontrolled chain reaction at a fuel cycle facility or national laboratory, performing the analyses that keep every operation subcritical. The team evaluates processes, sets mass and geometry limits, and reviews every change to fissile operations. You will build criticality models, write safety evaluations, and challenge operations that push boundaries. This role matters because a criticality accident is among the most severe events in the nuclear industry, and your analyses are the engineered guarantee it cannot happen. You will also conduct independent walkdowns of fissile operations, verifying that actual configurations match your evaluated assumptions. Your training programs will build a questioning attitude in operators, because the best criticality control is a worker who stops when something looks wrong. You will review non-routine operations with heightened scrutiny, since unfamiliar evolutions carry the greatest risk. Your safety evaluations will be living documents, updated whenever processes, materials, or assumptions change.

What you will achieve

• Complete criticality safety evaluations for all fissile operations with double contingency demonstrated and documented.
• Review process changes rapidly, providing safety approvals that never become the bottleneck for operations.
• Validate criticality codes against benchmarks, maintaining a qualified methodology regulators accept.
• Investigate and resolve any approach to safety limits with technically rigorous corrective actions.
• Deliver criticality safety training that gives operators genuine understanding, not just rule memorization.

What you will bring

Must-haves

• 2 to 5 years in criticality safety, nuclear safety analysis, or fissile material operations roles.
• Strong understanding of neutron multiplication, reactivity, and the parameters controlling criticality.
• Proficiency with Monte Carlo criticality codes such as MCNP or KENO including statistics interpretation.
• Knowledge of ANSI/ANS-8 standards and the double contingency principle in practice.
• Ability to write criticality safety evaluations meeting regulatory quality standards.
• Willingness to stop operations when safety limits are challenged: your authority must be real.
• Clear communication of complex neutronics concepts to operators and management.

Nice-to-haves

• Experience with DOE facilities and DOE Order 420.1C requirements.
• Familiarity with critical experiments and benchmark validation methods.
• Knowledge of criticality accident alarm system design and requirements.
• Advanced degree in nuclear engineering with criticality focus.