Three-dimensional transient analysis of Xi’an pulsed reactor by the coupled neutronics and thermal-hydraulics code

Abstract

In this paper, an integrated code is proposed to simulate the transient thermo-neutronic behavior of the Xi'an Pulsed Reactor (XAPR) core during reactivity insertion accidents (RIA), which is developed by coupling the neutron transport kinetics code DAISY and a parallel-channel thermal-hydraulics code based on the internal (master–slave) coupling scheme. The few-group parameters adopted in the simulations including the seven-group cross-sections and six-group delayed neutron precursors are calculated by the NECP-X code. The XAPR pulse operation data are first employed to validate the ability of the coupled code to perform dynamic analysis, and then transient characteristics of different parameters such as core power and fuel temperature due to the different form and magnitude of reactivity insertion has been further simulated and analyzed. The numerical results indicate that the coupled code is correct and suitable for the transient calculation of reactivity insertion in XAPR and is able to capture the main physics behind fast RIA transients.