17. Heat Exchangers

A number of technologies are being investigated for the Next Generation Nuclear Plant that will produce heated fluids at significantly higher temperatures than current generation power plants. The higher temperatures offer the opportunity to significantly improve the thermodynamic efficiency of the energy conversion cycle. One of the concepts currently under study is the Molten Salt Reactor. The coolant from the Molten Salt Reactor may be available at temperatures as high as 800–1000 °C. At these temperatures, an open Brayton cycle combined with a Rankine bottoming cycle appears to have some strong advantages. Thermodynamic efficiencies approaching 50% appear possible. Requirements for circulating cooling water will be significantly reduced. However, to realistically estimate the efficiencies achievable it is essential to have good models for the heat exchangers involved as well as the appropriate turbo-machinery. This study has concentrated on modeling all power conversion equipment from the fluid exiting the reactor to the energy releases to the environment.