Availability of cooling water has been one of the major issues in the selection of nuclear power plant sites. Cooling water issues have frequently disrupted the normal operation at some nuclear power plants during heat waves and long droughts. One potential solution is to use ice thermal storage (ITS) systems that reduce cooling water requirements and boost the plants' thermal efficiency in hot hours. The ITS uses cheap off-peak electricity to make ice and uses the ice for supplemental cooling during peak demand time. The ITS also provides a way to shift a large amount of electricity from off-peak time to peak time. For once-through cooling plants near a limited water body, adding ITS can bring significant economic benefits and avoid forced derating and shutdown during extremely hot weather. For the new plants using dry cooling towers, adding the ITS systems can effectively reduce the efficiency loss during hot weather so that new plants could be considered in regions with a lack of cooling water. This paper will review light water reactor cooling issues and present the feasibility study results. DOI: 10.1061/(ASCE)EY.1943-7897.0000089. (C) 2013 American Society of Civil Engineers.