LAUSR

Abstract In this study, the application of a 3D model for the sodium pool of the sodium-cooled fast reactor was realized. The basic equations and numerical solution methods of the model were given in detail. The model was verified by calculating the 3D temperature field of the region above the MONJU reactor core after the reactor was shut down and the pump stopped. Subsequently, the 3D sodium pool model was used to simulate and analyse the Chinese Experimental Fast Reactor (CEFR). The 3D temperature fields of the inner hot pool under the accidents of the control rod uncontrolled withdrawal and one primary pump shaft seizure at a 102.5% rated power were simulated to analyse the axial position where the thermal fatigue of the casing material was most likely to occur. The results showed that in the height range of 0.3–0.5 m of the enclosure, the thermal stratification phenomenon was the greatest, and the material was most prone to thermal fatigue.