高温气冷堆非纯氦气环境下高温合金碳迁移的化学动力学研究  

Study on Chemical Kinetics of Carbon Migration in Superalloys in the Non-Pure Helium Environment in High Temperature Gas Cooled Reactors

作　　者：郑伟 李昊翔 银华强[1] 何学东[1] 王秋豪 马涛[1] Zheng Wei;Li Haoxiang;Yin Huaqiang;He Xuedong;Wang Qiuhao;Ma Tao(Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing,100084,China)

机构地区：[1]清华大学核能与新能源技术研究院,北京100084

出　　处：《核动力工程》2021年第5期226-231,共6页Nuclear Power Engineering

基　　金：国家自然科学基金(11875176);国家重大科技专项经费项目(ZX069)。

摘　　要：高温气冷堆(HTGR)一回路冷却剂中的低含量杂质在HTGR超高温运行时会对堆内高温合金产生严重的腐蚀。其中高温合金与非纯氦气之间的碳迁移对于材料性能影响很大。本文探究了高温合金在非纯氦气环境中碳迁移的化学动力学原理,并基于此获得了判断材料脱碳和渗碳的理论判据。根据化学热力学和化学动力学原理,对非纯氦气环境的氧分压和碳活度进行了计算,指明CH4与H2O的分压比值较高时可能导致合金严重渗碳。在此基础上介绍了一种应用广泛的碳迁移模型——“铬的稳定相图”,分析了铬活度计算方法并归纳出取值建议。本文根据铬的稳定相图计算得到了清华大学设计的10 MW高温气冷堆(HTR-10)的实际运行工况下的腐蚀行为。The primary coolant in the high temperature gas cooled reactor(HTGR)contains impurities of low content,which will cause serious corrosion of the superalloys in the HTGR operating at the ultra-high temperature.In particular,the carbon migration between the superalloys and non-pure helium has a great influence on the material performance.This study explores the chemical kinetics principle of the carbon migration in the non-pure helium environment,from which the theoretical criteria for material decarburization and carburization are gained.Also,according to the chemical thermodynamics and kinetics principles,this study calculates the oxygen partial pressure and carbon activity in the non-pure helium environment,and indicates that a high partial pressure ratio of CH4 to H2O may lead to serious carburization of the alloys.On this basis,this study presents a widely used carbon migration model,“chromium stable phase diagram”,analyzes the chromium activity calculation method,and summarizes the recommended values.Finally,the corrosion behavior of the 10 MW HTGR(HTR-10)designed by Tsinghua University under the actual operating conditions is obtained by calculation based on the chromium stable phase diagram.

关 键 词：高温气冷堆(HTGR) 高温合金 腐蚀 脱碳 渗碳 

分 类 号：TL341[核科学技术—核技术及应用]