Spent-fuel storage and disassembly basins at heavy water reactor facilities have maximum allowable temperature and tritium activity levels to protect personnel from exposure to radiation from the tritiated water vapor emanating from these basins. Means of reducing this exposure by suppressing basin water evaporation through the use of monolayer films are presented. The effect of tritiated water on the performance of the monolayer film has been experimentally examined, and tritiated water does not detrimentally affect the film’s ability to reduce evaporation. Large-scale light water experiments have demonstrated that an octadecanol monolayer can reduce evaporation by ∼50%. A method for applying and maintaining a monolayer film over large areas with complex surface geometries has been developed. The results demonstrate the feasibility of using octadecanol monolayers to suppress evaporation from tritiated water pools.