Study of Transient Neutronic-thermalhydraulic Coupling: A Case Study Using a Backbone Interface

Abstract

Multi-scale, multi-physics computer simulations are increasingly utilized to enhance the predictive capabilities of transient behaviour in nuclear reactor operation to improve performance and safety. As a result, multiple computer simulations from different disciplines must exchange data during run-times to address these inter-dependencies. The Backbone, currently under development at the Canadian Nuclear Laboratories (CNL), is a hybrid code coupling framework using both Common Object Request Broker Architecture (CORBA) and Message Passing Interface (MPI) systems. Recently, major advancements have been achieved by synchronizing the coupling codes through the Time Step Controller (TSC). This paper presents progress made in enhancing performance of code coupling between the thermal-hydraulics code CATHENA with the neutron transport code 3D-Solver via the Backbone by comparing the simulation results to experimental data as well as the CPU time of the simulations. In addition, the strategies evaluated include a simple heuristic method and two more advanced third order controllers (the PID and General Third Order TSC). Both the PID and General Third Order TSC have demonstrated a performance gain of at least 100 times greater than non-TSC coupling.