A 50 Hz alternator is rated 500 MVA, 20 kV, with X_d = 1.0 per unit and X_"d = 0.2 per unit. It supplies a purely resistive load of 400 MW at 20 kV. The load is connected directly across the generator terminals when a symmetrical fault occurs at the load terminals. The initial rms current in the generator in per unit is __________