SLOSHING EFFECTS OF ADS-DF LEAD-BISMUTH PRIMARYCOOLANT CAUSED BY THE REFERENCE EARTHQUAKE

摘要

This paper deals with the analysis of the XADS reactor vessel filled by lead bismuth eutectic covered by apressurized Argon and subjected to seismic loads characterized by various level of ground accelerations. The socalledAccelerator Driven Systems (ADS) are made up of a proton accelerator and a subcritical reactor.The main aims of the analyses are: - to investigate the effects of the coupling between internal primarycoolant and vessel, - to determine the stress level of the reactor vessel due to an Operating Basis Earthquake aswell as to a Design Basis Earthquake,- to determine the influence of coolant sloshing on the stress level of thereactor vessel.The effect of the interaction between vessel and primary coolant was determined by comparing the resultsby means of two numerical models: one in which the fluid has been simulated as lumped masses connected tothe internal nodes of the vessel and the other which considers a coupling between the vessel (simulated by meansof a Lagrangean elements ) and the fluid (simulated by means of Eulerian elements).The analyses highlighted the importance of the interaction between the fluid and the reactor vessel in termsof both the level of the stress and the distribution. The results showed that if the fluid masses are concentrated onthe internal nodes of reactor vessel the maximum stresses are underestimated and the actual point of maximumstress is not located. The point of maximum stress for this model is located near the constraint of the reactorvessel on the support structure while in the model with fluid interaction the most stressed point is at the vesselbottom.