Dalek Asylum

The Dalek Asylum was a snowy and mountainous Planet used by the Daleks as a prison and "dumping ground" for those among them who had malfunctioned, gone insane and/or become mentally scarred by battles. The sane Daleks left their insane fellows in the Asylum rather than kill them because they epitomised the Dalek concept of beauty: pure hatred. (DW: Asylum of the Daleks)

Even amongst the deranged Daleks, there was still an area described as "intensive care", which housed several Daleks who had survived conflicts with the Doctor on planets such as Spiridon, Kembel, Aridius, Vulcan, and Exxilon.

History
After the Alaska crashed on the planet, the Parliament of the Daleks feared the defective Dalek inmates could escape. In order to destroy the planet and the Daleks inhabiting it, they kidnapped the Eleventh Doctor, Amy Pond, and Rory Williams, and sent them to the surface in order to deactivate the planet's defences, as no Dalek was willing to infiltrate the Asylum themselves due to fear of the insane Daleks.



After doing so, the Doctor and his companions managed to use a transporter to escape to the TARDIS on board the Dalek ship before the Asylum was destroyed. (DW: Asylum of the Daleks)