目的 在模拟压水堆一回路水化学环境中开展加锌对316LN应力腐蚀开裂行为研究，获得加锌对316LN腐蚀影响特性。方法 通过直流电位降方法获得316LN在不加锌和加锌水化学中的裂纹扩展速率，对比分析不同应力强度因子下加锌对316LN裂纹扩展速率影响，利用扫描电镜、透射电镜分别对316LN应力腐蚀断口形貌以及裂纹尖端元素分布进行观察和分析。结果 在不加锌水溶液中，应力强度因子K=38.5 MPa.m^1/2，裂纹扩展速率为2.80×10⁻⁸ mm/s，应力强度因子K=45.5 MPa.m^1/2，裂纹扩展速率为3.51×10⁻⁸ mm/s;在加锌水溶液中，应力强度因子K=38.5 MPa.m^1/2，裂纹扩展速率为1.29×10⁻⁸ mm/s，应力强度因子K=45.5 MPa.m^1/2，裂纹扩展速率为1.74×10⁻⁸ mm/s;在加锌或不加锌水溶液中，应力强度因子对316LN裂纹扩展速率有促进作用，但在相同应力强度因子下，随锌的加入，316LN裂纹扩展速率降低46.0%～49.5%，使316LN生成保护性更好、韧性更高的氧化膜。结论 冷却剂加锌有利于提高316LN抗应力腐蚀开裂的能力。

The work aims to study the effect of zinc on stress corrosion cracking behavior of 316LN in primary hydrochemistry environment of simulated pressurized water reactor and obtain the effect law of zinc on corrosion of 316LN. The crack growth rates of 316LN were obtained by direct current potential drop method (DCPD) in hydrochemistry environment without zinc or with zinc. The effect of zinc on the crack growth rates of 316LN under different stress intensity factors was analyzed. The fracture morphology of 316LN due to stress corrosion and the distribution of elements at the crack tip were observed and analyzed by scanning electron microscopy and transmission electron microscopy. In the aqueous solution without zinc, the crack growth rate was 2.80×10−8 mm/s when the stress intensity factor K was 38.5 MPa.m1/2 and the crack growth rate was 3.51×10−8 mm/s when the stress intensity factor K was 45.5 MPa.m1/2. In addition, in the aqueous solution with zinc, the crack growth rate was 1.29×10−8 mm/s when the stress intensity factor K was 38.5 MPa.m1/2 and the crack growth rate was 1.74×10−8 mm/s when the stress intensity factor K was 45.5 MPa.m1/2. In the aqueous solution with or without zinc, the stress intensity factor promoted the crack growth rate of 316LN, but under the same stress intensity factor, with the addition of zinc, the crack growth rate of 316LN decreased by 46.0%~49.5%, which made 316LN form an oxide film with better protection and higher toughness. Adding zinc to the coolant is beneficial to improving the stress corrosion cracking resistance of 316LN.