Waste disposal systems for closed cycle water reactor power plants were developed for the Shippingport, Yankee Rowe, and Connecticut Yankee plants in turn. Waste largely originates from moving water in and out of the reactor due to thermal expansion, for adjustment of boric acid concentration, and for control of tritium concentration. Escape of hydrogen from the coolant gives rise to gaseous waste. Recycling of boric acid and hydrogen reduces the waste discharge, but some water must be discharged to reject tritium. Evaporation provides strong leverage for water purification; it is proposed to send some evaporator vapor up the stacks for tritium and organic concentration control. Stripping hydrogen from the coolant to be processed before boric acid concentration simplifies the gas handling problem, while charcoal adsorption greatly reduces radioactive gas discharge to the atmosphere. No waste discharge to the plant environment is within grasp.