Abstract: Fuel rods experience the heat up process several times during the loss of coolant accident (LOCA). Swelling and rupture will happen if the temperature rises to a certain degree which will have great effect on the LOCA process. Both the inside and outside of the fuel cladding will be oxidized, and this will exacerbate the Zr-H2O reaction. In this study, code ARSAC-K is used to analyze the LOCA process in the generation-III nuclear power plants designed and constructed by China. In order to study the effect of rod swelling and rupture on the LOCA process, several power shapes are chosen. It is found that at the moment of rod rupture, the temperature of the rod cladding will decrease in a few tens of seconds. After few tens of seconds, the cladding temperature continues to rise till the peak cladding temperature is reached.