Most of the light water reactor power plants now operating or under construction use pressurized-water reactor (PWR). They are suffering of relatively low thermal efficiency which is around 33%. This would not only have a negative impact economically but also incurs environmental burden in terms of thermal pollution. In this paper, nuclear steam supply system of a typical PWR has been taken into consideration using 1000 MWe Bushehr nuclear power plant (BNPP) data. It is shown thermal efficiency could conceivably be increased by superheating live steam with natural gas up to around 40%, competing with similar fossil-fueled power plants. It is further shown that fuel cost (natural gas) as low as 0.12 Cent/MWe, extra power generated is feasible.