PWR蒸気発生器蒸気量増大に関する研究（フィンおよびねじり板導入による伝熱改善）

Abstract

Increasing the electric power of nuclear power plant is important for the economy and the environment. Pressurized water reactor (PWR) exchanges the heat of primary system with secondary system in the steam generator (SG) to generate vapor. In this study, the steam generator of PWR was focused on. A prediction method to estimate the vapor mass flow rate of steam generator has been developed. In the method, the heat transfer from the primary system to the secondary system can be categorized into the following types. (1) Heat transfer from the primary system to the heating tube. (2) Heat conduction of the heating tube. (3) Heat transfer between the heating tubes and the secondary system. The liquid in the primary system is in the single-phase, while the liquid in the secondary system is in both single-phase and two-phase. In this research, the Colburn's equation and the Chen's equation to calculate the heat transfer coefficient for both single-phase and two-phase were used, while using the Saha-Zuber's equation and the Clark-Rohsenow equation to calculate the vapor mass flow rate at the sub-cool region. In addition, vapor mass flow rate of the steam generator with the axial economizer is compared with that of the current SG to evaluate the merit of the axial economizer. Moreover, we added fins and twisted tape to the current steam generator with the axial economizer as an approach to increase the vapor mass flow rate. Then, the rate of heat transfer and the temperature difference between the primary system and the secondary system were compared to inspect the economizer, fin, and twisted tape. As a result, vapor mass flow rate has increased about 3% by the combination of the external fin and twisted tape.