Flow Instability Analysis of Supercritical Water-Cooled Reactor CSR1000 based on Frequency Domain

Flow instability of Supercritical Water-cooled Reactor CSR1000 was studied and mathematics model of core in supercritical water-cooled reactor CSR 1000 was established.A code named FREDO-CSR1000（Frequency domain analysis of CSR1000） and a code named TIMDO（Time-Domain Method） have been developed to analyze the flow instability of Supercritical Water-cooled Reactor CSR1000 after the codes was verified.The results show that the shape of stability map obtained by the two different methods are very similar,both of which are divided into two regions,respectively corresponding to two types of flow instability,namely the flow drift and the density wave oscillation instability.Besides,it is also found that the operation points of CSR1000 calculated by the frequency domain method and time domain method are both in the safety operation region.,which are far away from the unstable region.