Which term is the single number assigned to a package, overpack, or freight container to provide control over radiation?

• A. Contamination
• B. Containment System
• C. Activity
• D. Transport Index

Answer: (D)

In radioactive material transport, the number used to control radiation exposure from a package is the Transport Index. This single value represents the radiation level at a distance of 1 meter from the package surface and is used to determine handling requirements, segregation, and eligibility for different transport modes. It reflects how much radiation a person could be exposed to at a safe distance during transport, independent of how much radioactive material is inside.

This differs from the total amount of radioactivity inside the package, known as activity, which tells you how much radionuclide is present but not how it translates to exposure at a distance. Contamination refers to radioactive material on surfaces or in the environment, and a containment system is the packaging designed to prevent leakage. The Transport Index is the specific measure used to control radiation exposure during the transport process.