HTGR Knowledge Base

Conference Article: Coupling of Neutronics and Thermal-Hydraulics Codes For The Simulation of Transients of Pebble Bed HTR Reactors

Abstract

The Pebble Bed Reactor plant is a concept of an inherently safe nuclear power plant. This paper presents the coupling of the SIEMENS INTERATOM-developed and licensed 2D neutron diffusion code KIND with the commonly used thermal-hydraulics code THERMIX to simulate very fast transients of High Temperature Reactors (HTR). This is possibly by using more up-to-date thermal-hydraulic models and a more detailed heterogeneous particle model for the fuel kernels. Furthermore, THERMIX is implemented in the steady-state ZIRKUS modular code system which provides necessary initial conditions for the transient code and nuclear data base (macroscopic cross sections) as well. Additionally, a Graphical User Interface (GUI) called SIMPLAT is designed to simplify the input creation and the results analyses for ZIRKUS as well as for KIND. Moreover, the 1D-KIND transient code is coupled with the graphic development software LabView1 to prove the possibility of a runtime interactive intervention of the user during the calculation. This interactive intervention enables to introduce parameter changes while the code is already running. To study the influences of reactivity transients which causes effects that are as fast as the relaxation time for heat exchange between the fuel particles (~ 10 ms) and the surrounding graphite. Results of heterogeneous and homogeneous simulations are compared and show an erroneous overestimation of the maximum power (by one order of magnitude) for the homogeneous model, since the Doppler effect is calculated based on the homogenized and not the real fuel temperature.

view the full text of this article (15 pages, format: PDF, size= 534kB)

Reference:

Proceedings of the Conference on High Temperature Reactors, Beijing, China, September, 22-24, 2004

International Atomic Energy Agency, Vienna (Austria)

HTR-2004, pp:1-15