10 C.F.R. § 71.83 Assumptions as to unknown properties.
Title 10 - Energy
When the isotopic abundance, mass, concentration, degree of irradiation, degree of moderation, or other pertinent property of fissile material in any package is not known, the licensee shall package the fissile material as if the unknown properties have credible values that will cause the maximum neutron multiplication.
Title 10: Energy
PART 71—PACKAGING AND TRANSPORTATION OF RADIOACTIVE MATERIAL
Subpart G—Operating Controls and Procedures
§ 71.83 Assumptions as to unknown properties.
