Simulation of heat and momentum transfer in the high temperature test reactor

Abstract

The world energy consumption is projected to increase by 60 percent over a 21-year forecast horizon. Using the full potential of the world's uranium and thorium resources, nuclear power can supply a large share of the world's energy needs for many thousands of years. Although nuclear power provides a compelling option, it must overcome the problems that gave it a negative reputation in order to gain public and political support. To overcome these problems new fourth generation nuclear reactors are being developed that are cheaper to run, are safer and have a longer lifetime. High Temperarure Gas Reactors (HTGR) are fourth generation reactors that are currently being researched around the world. Two examples of HTGRs are the Pebble Bed Modular Reactor (PBMR) developed by the South Afiican utility ESKOM and the High Temperature Test Reactor (HTTR) developed by JAERI. HTGRs are complex systems and various groups around the world are in the process of developing simulation codes for these types of reactors. The purposes of these codes are to aid with the design of HTGRs. The purpose of this study was to develop a computer simulation model of Japan's High Temperature Test Reactor as part of an international effort to validate different simulation codes. The model developed in this study will specifically be used for the validation of Flownet, the code used by Eskom for the design of the PBMR. The model was built by using Xnet, an explicit thermal-fluid network analysis code. The Xnet model was then compared to the HTTR model in the implicit thermal fluid network code, Flownet. The behaviour of the HTTR models was' thoroughly investigated for steady-state, as well as transient flows. The results of the Xnet model compared very well with the Flownet results, which is an important first step in the verification of both Xnet and Flownet.