Investigation on the hydraulic process of inertia tank in the case of pump trips

Abstract

The inertia tank (IT) used in the deep pool-type nuclear reactor (DPR) is a novel design to reduce the decrease rate of core flow in the early stage of loss of flow accident. Under the action of IT, the reactor can be safely reduced to low power conditions. In this paper, based on cold state condition, the hydraulic process of IT is studied by experiment. Furthermore, RELAP5 is used to simulate hydraulic process of IT and the results show that RELAP5 can well simulate the variation of water level and mass flow during the working process of IT. The maximum relative error of water level and mass flow are 0.5% and 5.6%, respectively. Based on the RELAP5 model, the influences of flow resistance on the hydraulic process of IT are studied. The research results show that the hydraulic process of IT is significantly affected by the flow resistance in both upstream part of IT (UIT) and connection pipe (CP), while the flow resistance in downstream part of IT (DIT) has little effect on the hydraulic process of IT. In addition, the differences between IT and primary pump with flywheel are compared by the means of RELAP5. The research in this work can provide reference for the design of IT.