Study on Influence of Zinc Injection on Fuel Crud and Radiation Field in Non-first Cycle in PWR

The corrosion products in the primary loops of PWR will form crud on the surface of fuel cladding, leading to the risk of CIPS and aggravating the corrosion of the cladding, while Co element deposited in the crud greatly increases the radiation field dose. As early as the 1990s, American PWR has begun to implement zinc injection to remove crud and reduce radiation field, and has accumulated a lot of experience in zinc injection, while zinc injection has just started in Chinese PWR. In this paper, the fuel crud analysis software independently developed by CGN Research Institute was used to study the effect of non-first cycle zinc injection on cladding crud and radiation field. The results showed that compared with first cycle zinc injection, the Ni/Fe ratio, 58Co activity, crud mass and boron mass would decline more slowly. However, compared with the condition without zinc injection, the effect of zinc injection is more obvious. The research results can offer valuable insights for the implementation of zinc injection in China.