核电厂一回路钝化研究

Study on Passivation of Primary Circuit of Nuclear Power Plant

在核电厂一回路的设备表面形成致密的钝化膜是核电厂热态功能试验的一项重要工作。钝化膜的质量直接影响核电厂带核运行期间的辐射源项。因此,做好热态功能试验期间一回路的钝化具有重要意义。热态功能试验期间化学控制决定着钝化膜的质量,本文首先简要分析了国内核电商用各堆型水化学的特点,其次分析了一回路冷却剂运行温度下的pH值(pHT)的影响因素和硼碱曲线。重点分析了国内4种堆型的钝化应用实例,并讨论了钝化膜形成的化学控制机理,最后对一回路钝化期间的化学控制给出改进措施。

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(pHT) 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.