Atomic matter pile
The atomic matter piles were energy-production components utilized in Federation starship propulsion systems.

In 2254, Starfleet officer Benjamin Finney, while serving aboard the , accidentally left a circuit open to the atomic matter piles, a mistake which could have resulted in the destruction of the ship. This oversight was logged by Finney's old friend, Ensign James T. Kirk, who subsequently closed the switch, and Finney was moved to the bottom of the promotion list as a result. This led to a rift in the friendship between Kirk and Finney. ()

See also
 Energy pile
 Nuclear reactor
Propulsion technology