The analytical and research capabilities of a research reactor are determined primarily by the available thermal neutron flux. This database categorises research reactors as a low flux, medium flux, or high flux reactor according to the following levels of thermal neutron flux:

• low flux reactor (< 10¹² n/cm2/s)
• medium flux reactor (≥ 10¹² n/cm2/s and < 10¹⁴ n/cm2/s)
• high flux reactor (≥ 10¹⁴ n/cm2/s)