Criticality safety analytical methods


Criticality is the state of a nuclear reactor when there is a self-sustaining chain reaction of fissionable material. Criticality safety analysis relates to evaluation approaches in data and computational code development for certain types of criticality safety problems.

The NEA has engaged in assisting members with cross comparison and development of analytical methods for criticality safety analysis.

Ongoing activities

  • SG-1: Role of integral experiment uncertainties and covariance data in criticality
    safety validation
  • SG-2: Blind benchmark on MOX damp powders
  • SG-6: Statistical tests for diagnosing fission source convergence and undersampling in Monte Carlo criticality calculations

Major areas of work

  • Benchmarks
    • Fissile arrays
    • Fissile solutions
    • Transport of materials
  • Monte Carlo methods
    • Source convergence
    • Undersampling
    • Variance reduction
  • Sensitivity and uncertainty analysis
    • Cross-section adjustment
Publications and reports