U.S. Nuclear Regulatory Commission
(a) Under 10 CFR 20.1904, what is a container?
(b) How big can a container be?
(c) Can a room be considered a container?
(d) Is a transportation cask a container when it is not being transported?
(e) Are vehicles (e.g., trailer of a tractor-trailer) containers?
(a) In the context of 10 CFR 20.1904, and in accordance with Health Physics Position (HPPOS) 28, a container is a receptacle in which radioactive material is held or carried.
(b) There is no limit to the size of a container.
(c) Typically, a room is not considered a container; it is considered an area, and should be posted as such.
(d) A transportation cask or package in certain circumstances could be a container. If a container is in transport and packaged and labeled in accordance with Department of Transportation (DOT) regulations, it is exempt from the labelling requirements of 10 CFR 20.1904. If, however, the container / cask / package is not in transport, it is subject to the labelling requirements of 10 CFR 20.1904.
(e) Under certain circumstances, the trailer of a tractor-trailer could be considered a container.
(Reference: 10 CFR 20.1904, HPPOS 28)