During the normal operation of pressurized water reactors, tritium contributes more than 95% of the total activity of liquid phase effluent from pressurized water reactors, and it is one of the key radionuclides in reactor design and operation. Through in-depth data cleaning and analysis of tritium emission data from eight units operating in the United States with very similar core designs from 2000 to 2019, it is concluded that tritium emission from Sb-Be secondary neutron sources using stainless steel cladding is one of the important sources of tritium source terms for pressurized water reactor units. According to statistics, the average contribution of tritium production from secondary neutron sources in the units is 7.5 TBq·a^-1, combined with theoretical calculations, The penetration ratio in line with the current cladding material development and operation management level is 10%-20%. The elimination of secondary neutron sources can reduce the public dose caused by tritium emissions by about 20%, and can also reduce the constraints of tritium source terms on the number of units planned for the plant site. In addition, it also found that significant fluctuations in tritium emissions are significantly affected by concentrated liquid emissions, especially before or during the overhaul of pressurized water reactors in the United States, which will help optimize the management of radioactive emissions from future units.