Atomic demolition munition
Atomic demolition munitions (ADM), sometimes inaccurately called atomic land mines, were nuclear weapons intended for manual emplacement, to be triggered by a remote control or a timer. Their principal application was countermobility by a retreating ground force, destroying bridges or collapsing mountain passes through which the enemy had to advance. In other words, the primary intent was to block access, not directly kill troops, although some scenarios did envision contaminating a route through which enemy forces would pass.
They were made in various sizes, typically truck-borne or portable by strong men. The man-portable versions, such as the U.S. Special Atomic Demolition Munition based on the W54, might be used in direct action missions by special operations forces, such as hand-emplacing the explosive against a dam or in a critical industrial plant that, for various reasons, could not be attacked from the air.
While the man-portable ADMs have been called "suitcase atomic bombs", that, as far as is known, is an overstatement. The smallest W54 physics package weighed 26.5 kg/58.5 pounds. When packaged for use, with power supplies, carrying frame, etc., it was a large backpack weighing over 45.4 kg/100 pounds. In training, mockups were delivered by highly trained troops using parachutes, but would not be able to move far on the ground.
Nuclear explosives for peaceful construction purposes bore some similarity to ADMs, but were generally higher-yield.