Geothermally Heated Replacement Water in Pressurized Water Reactors

In pressurized water reactors, about 5% of the water used in the energy production process is lost in the evaporative cooling process. Cold water is then used to replace this lost water and must be preheated back to saturation before entering the boiler of the plant to be converted to steam. This leads to a decrease in efficiency, as energy is needed to reheat this water, creating a loss in power. We hypothesized that geothermally heated replacement water would increase the efficiency of a nuclear power plant. We simulated a rankine cycle inside a nuclear power plant using python, with boundary pressures of 4000 and 16e^6 pascals, and an isentropic efficiency of 80% in the modeled turbine. We found that geothermally heated replacement water linearly increased the efficiency of the plant as a whole. Modeling temperatures from 15 to 80 degrees celsius increased the total efficiency of the cycle by 0.87%, which is an estimated 260 megawatt increase in output. We believe that this method could be useful in the future when deciding on cites for nuclear power plants as building near geothermal sources could increase efficiency of the plant overall.