Several important issues related to impurity control in tokamak reactors were studied with a version of the plasma transport code WHIST. These issues are burn control feasibility by impurity injection and enhanced ripple transport, the effect on the plasma of limiter sputtered impurities, and the effect of operating with a self-pumped helium removal system. It was found that the plasma operating point and the mix between radiated power and power transported to the limiter can be controlled by varying the amount of impurities injected, the ripple transport, and the pumping fraction. It was also found that a self-pumped impurity control scheme that removes helium but not hydrogen results in acceptable plasma profiles. Finally, the effects of sputtered impurities depend greatly on whether or not neoclassical impurity transport is assumed, with the nonneoclassical case giving more favorable results.