Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, that adjust a high-pressure feeder of a feed system used in pulp production based on the fluid leakage through a low-pressure outlet of a high-pressure feeder. Methods can include obtaining multiple flow values, including (1) a make-up liquor flow value, (2) a black liquor flow value, (3) a white liquor flow value, (4) a chip chute circulation flow value, and (5) a high pressure feeder purge flow value. Methods can include determining a chip flow value specifying a flow of chips provided to the high-pressure feeder. Based on the flow values, methods can determine a fluid leakage value specifying an amount of fluid leakage through a gap between a pocket rotor and the housing of the high pressure feeder. Methods can adjust an annular gap based on the fluid leakage value satisfies a threshold leakage value.