An impeller rotor includes a plurality of fluid circuits arranged circumferentially about an axis within the impeller rotor. Each of the fluid circuits includes a first outlet passage, a second outlet passage and an inlet passage fluidly coupled to the first outlet passage and the second outlet passage in parallel. A seal runner includes a bore, a sidewall and a rim. The bore is fluidly coupled to the first outlet passage of each of the fluid circuits. The rim projects radially out from the sidewall to an outer end of the rim. The rim is seated in a recess in the impeller rotor. The rim includes a flat disposed at the outer end of the rim. The flat of the rim is configured to engage a flat of the impeller rotor to rotationally fix the seal runner to the impeller rotor.