The Temporal Extinction Device was a weapon of Dalek design used by the Dalek Empire.
One device was deployed in a time fissure by a Dalek vessel within the Time Vortex. This caused instability. The Dalek time ship was swamped by a tidal wave of temporal energy.
With the failure of the Dalek forces to manipulate the time fissure, they attempted to create a second device by using a nuclear reactor. (AUDIO: The Time of the Daleks)