CONTROL STRATEGIES FOR VHTR GAS-TURBINE SYSTEM WITH DRY COOLING

An original control strategy for very high temperature reactor (VHTR) gas-turbine system with dry cooling against ambient air temperature fluctuation was established in order to enable the freedom of site selection wherever desired without significant drawbacks on the performance. First, the operability of power conversion system and degradation of power generation efficiency were examined considering not only the thermodynamics but also the mechanical efficiency of compressor based on detailed performance map derived from experimental data. Second, control simulations for large ambient temperature fluctuations were conducted by system analysis code with the built-in control strategy. In addition, the sensitivity of power generation efficiency for typical steam cycle with dry cooling to ambient air temperature changes was assessed for the comparison. It was shown that the design goal can be effectively met simply by monitoring and controlling a few of key operating parameters such as reactor outlet temperature, primary coolant pressure. Furthermore, distinctive advantages of the VHTR gas-turbine system over nuclear power plant employing Rankine cycle was demonstrated when installing in inland area.