Abstract: An integrated CFD model was built in which the main components of the first loop are included.The intermediate heat exchanger,decayed heat exchangers,reactor core and main pump are simulated by the method of additional source term.The integrated model is closer to the real situation as there are not artificial assumed boundary between various components.The integrated model are justified after the results were compared with CEFR design values.It shows that sodium pool were divided into low temperature cold sodium pool and high temperature hot sodium pool.The temperature difference in hot sodium pool is large,which indicate that the hot and cold fluid mixing is obvious in the hot pool.Meanwhile,the average temperature changes little at different height of cold sodium pool and hot sodium pool,which indicate that the heat shield separating the hot and cold sodium pools effects well.