Polymer induced turbulent drag reduction in a rotating disk apparatus was investigated using four different molecular weights of nonionic poly(ethylene oxide) (PEO) in synthetic seawater for potential application to cold water piping in the Ocean Thermal Energy Conversion (OTEC) system, The linear correlation between polymer concentration (C) and C/DR for different molecular weights of PEO and a universal correlation are obtained. In addition, to measuring the drag reduction efficiency change during the operation period, the drag reduction behavior is measured as a function of time, and the results obtained from this experiment are then correlated with Brostow＇s equation for polymer degradation. From this study, the drag reduction effect induced by polymer additives is found to be applicable to the OTEC plant to reduce the pumping energy cost.