A seal ring for a radial separation seal includes a first ring segment comprising a male portion and a second ring segment comprising a female portion. The female portion is configured to engage the male portion in the manner of a tongue and groove joint. The joint includes an inner interface at which the first ring segment abuts the second ring segment, the inner interface comprising two inner sealing surfaces; and outer interface at which the first ring segment abuts the second ring segment the outer interface comprising two outer sealing surfaces. The outer interface is radially outward from the inner interface so that when the first ring segment is in an engaged position with the second ring segment so that when a fluid flow provided to the inner interface, fluid pressure from the fluid flow pushes the inner sealing surfaces of the inner interface apart.