Study on Passivation of Primary Circuit of Nuclear Power Plant

It is an important work to forming a dense passivation film on the surface of the primary equipment in the hot functional test (HFT). The quality of the passivation film directly affects the radiation source term during the nuclear operation of the power plant. Therefore, it is of great significance to do a good job in the passivation of primary circuit during the HFT. Chemical control determines the quality of passivation film. This paper first briefly analyzes the characteristics of water chemistry of various types of nuclear power reactors in China, and then analyzes the influencing factors of pH value (pH_T) and boron-alkali curve at the operating temperature of primary coolant. The passivation application examples of four types of reactors in China are emphatically analyzed, and the chemical control mechanism of passivation film formation is discussed. Finally, the improvement measures for chemical control during primary circuit passivation are given.