The following terms are used by the U.S. Defense Department to identify different classes of incidents involving nuclear weapons: 

BROKEN ARROW - Theft, loss, or unauthorized detonation of a nuclear weapon.
BENT SPEAR - A major accident involving a nuclear weapon.
DULL SWORD - A minor incident involving a nuclear weapon.
FADED GIANT - An accident involving a nuclear reactor or other non-explosive device.
ROGUE SPEAR - Possession of a nuclear weapon by a non-governmental power.