A conceptual design, performance analysis, system optimization and simulation of an OTEC (Ocean Thermal Energy Conversion) power plant was carried out in the present study. The OTEC plant acts as the bottom cycle of the Third Nuclear Power Plant, utilizing the warm water discharged from the nuclear plant as the heat source and the cold deep seawater pumped from the nearby sea bottom as the heat sink. The nominal net power output from the OTEC plant is estimated to be 8.74 MWe. A plant simulation was further carried out to study the OTEC plant performance due to seasonal variation of the warm water temperature, which shows that the OTEC plant is able to deliver an electricity of 5.18×107kWH per year. The net power output in the winter season will be reduced to about one eighth of that in the summer season. The final discharged warm water temperature was shown to be below 29°C all year around, so that the current thermal pollution problem of the nuclear power plant can be eliminated. Additionally there is the side benefit of 8.74 MWe net power generation from ocean energy resource. This OTEC plant will become economically feasible if the installation cost is considered as a thermal pollution control investment.