Buddha said " Satta "..in many Suttas.
the meaning is " clinker person " 
who clinging in 5 aggregates. 

This " Satta "..is developing the 8 noble paths and ending suffer.
And call person who " Nibbana of suffer "..
as.. Arahunt or Deathless or Unconditioned-element.

This is not " Permanent Ataman in Upanishad view "...
I don't know why Buddhist seems to avoiding 
" Satta(clinker) - Puggalo(person) "...