Genesis Ark

The Genesis Ark was a Time Lord prison ship built on Gallifrey, it was designed to contain all Daleks captured by the Time Lords. The only way for the Genesis Ark to be activated is for it to be touched by a being that has time travelled, so that the Daleks themselves could not reactivate it if they got hold of it. A time traveller carries a sort of background radiation that normal beings do not. (DW: Doomsday)