Regularly admits shutdown a revelation (10)
I believe the answer is:
disclosure
'a revelation' is the definition.
(synonyms)
'regularly admits shutdown' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'shutdown' becomes 'closure' (synonyms).
The alternating letters of 'admits' are 'dis'.
'dis'+'closure'='DISCLOSURE'
(Other definitions for disclosure that I've seen before include "broadcast" , "Laying bare" , "Release" , "revealing" , "Publication" .)