Nuclear Techniques ›› 2020, Vol. 43 ›› Issue (4): 40006-040006.doi: 10.11889/j.0253-3219.2020.hjs.43.040006


Model analysis of the influence of coolant impurity on the properties of high temperature alloys of HTGR

Qiuhao WANG1,2,Haoxiang LI1,2,Wei ZHENG1,2,Huaqiang LI Shengqiang HE Xuedong YIN1,2(),Tao MA1,2   

  1. 1.Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084, China
  • Received:2020-02-01 Revised:2020-03-30 Online:2020-04-15 Published:2020-04-20
  • Contact: Huaqiang LI Shengqiang HE Xuedong YIN
  • About author:WANG Qiuhao, male, born in 1991, graduated from Beijing University of Chemical Technology in 2015, master student, major in nuclear science and technology
  • Supported by:
    National Natural Science Foundation of China (NSFC)(11875176);the Major National Science and Technology Projects of China(No.ZX069)

Abstract: Background

The small amount of CO, H2, H2O and CH4 and other impurities existed in the primary coolant of high temperature gas-cooled reactor (HTGR) has important influence on the high temperature properties of high temperature alloys for HTGR. A great number of studies have been carried out on this aspect. Due to the difficulty in controlling the trace impurity content in experimental helium gas during the research process, the distribution of relevant research results is relatively scattered, so appropriate models need to be induced analysed.


This study aims to review two research methods and their applications for the influence of helium impurity in coolant on the properties of high temperature alloys under the very-high temperature operation of HTGR.


First of all, the composition and source of impurities in the primary coolant of HTGR were introduced, and the corrosion mechanism of the alloy in the impure helium of HTGR was analyzed. Then two widely used theoretical models, i.e., the stability diagram for chromium model and the ternary environmental attack (TEA) diagram model, were compared and investigated, and some applications of the two methods were reviewed. Finally, the oxygen partial pressure and carbon activity of helium gas of three HTGR coolants were calculated based on the impurity limit data of high temperature reactor using the stability diagram for chromium model. [Results and


The stability diagram for chromium model has been widely used to analyze the effect of helium impurity content on the properties of nickel-chromium alloy materials, and its rationality has been verified. The TEA diagram model can specify the allowable impurity levels and provide the basis for reactor gas impurity control. However, it has not been widely used due to the need for many tests in determining the boundary.

Key words: HTGR, High temperature alloy, Coolant, Impurity phase diagram model

CLC Number: 

  • TL341