From confine +‎ -ation.

confination (uncountable)

1. (rare, nonstandard) The quality of being confined.
   • 1857, The Southern Journal of the Medical and Physical Sciences:

     Predisposed to consumption in no other way, only by confination of body; he was somewhat stooped over, and flat-chested; one side a little more flattened than the other[…]

• nanofiction