Crucible energy core
From Tardis Wiki, the free Doctor Who reference
The Crucible energy core was the power source of the Crucible. The core consisted of Z-Neutrino energy.
A shaft ran from the vessel's bridge down to the core. The TARDIS, its defenses taken down, was dropped into this shaft and fell into the core. It would seem that, were it not for the intervention of the Meta-Crisis Tenth Doctor, the energy would have destroyed the TARDIS. (DW: Journey's End)
