Transportation package:

In the context of this report, containers used for the transport of spent fuel or high-level waste, whether loaded or empty. Loaded packages are referred to as packages in international standards, whereas the containers themselves without their contents are referred to as packagings. The terms casks and flasks (the latter term is commonly used in the United Kingdom) are sometimes used synonymously with packages. This report distinguished between two types of transportation packages: bare-fuel packages in which the spent fuel and the fuel basket are placed directly into the package, and canister-based packages in which the spent fuel and fuel basket are placed into a welded steel canister that in turn is placed in the package.

Transuranic waste:

Radioactive waste containing long-lived radioactive transuranic elements (elements with atomic numbers greater than 92) such as plutonium in concentrations greater than 100 nanocuries per gram.

Truck package:

A transportation package designed to be transported by road.

Type A package:

A package designed for the transport of materials of limited radioactivity—for example, uranium hexafluoride and fresh nuclear fuel.

Type B package:

A package designed for the transport of larger quantities of material including spent fuel, high-level waste, and mixed oxide fuel.

Type C package:

A package designed for the air transport of quantities of radioactive material exceeding a defined threshold including, for example, plutonium and mixed oxide fuel.

Uranium (U):

A naturally radioactive actinide element with atomic number 92.

Very long duration fires:

Fires that burn for periods of hours (or longer), which can produce thermal loading conditions that exceed those for the regulatory thermal test specified in 10 CFR 71.73.

Vitrification:

A process for immobilizing radioactive waste, particularly high-level waste, in glass matrices.

Vulnerable communities:

Communities of people who, because of disproportionate exposures to other health-affecting substances, or because of ethnic, linguistic, or socioeconomic issues, may be less able to read or understand information from the authorities, to act in a first-responder role, to exit the area in a timely manner in an emergency, or to otherwise cope with an emergency.