ONE-DIMENSIONAL REACTOR MODEL FOR THE INTEGRATED SIMULATION OF THE PBMR POWER PLANT

The Pebble Bed Modular Reactor (PBMR) power plant is currently being developed by PBMR (Pty) Ltd in South Africa together with ESKOM and other industrial partners. This high temperature gas cooled reactor (HTGR) plant is based on a three-shaft Brayton cycle with helium gas as coolant. The complexity associated with the thermal-hydraulic design of the cycle calls for the use of a variety of analysis techniques and simulation tools. One of the most prominent of these is the Flownet thermalhydraulic network simulation software. Flownet allows detailed steady-state and transient thermal-hydraulic simulations of all components in the plant fully integrated with core neutronics and controller algorithms. This paper describes the theory and integration of the neutronics and thermal-hydraulic models for the reactor core and presents sample calculations to illustrate the results obtained.