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Science and Technology of Nuclear Installations
Volume 2016 (2016), Article ID 6419124, 9 pages
http://dx.doi.org/10.1155/2016/6419124
Research Article

Oxidation Analyses of Massive Air Ingress Accident of HTR-PM

Wei Xu,1,2,3 Yanhua Zheng,1,2,3 Lei Shi,1,2,3 and Peng Liu1,2,3

1Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
2Collaborative Innovation Center of Advanced Nuclear Energy Technology, Beijing 100084, China
3Key Laboratory of Advanced Reactor Engineering and Safety, Ministry of Education, Beijing 100084, China

Received 12 April 2016; Revised 20 June 2016; Accepted 22 June 2016

Academic Editor: Eugenijus Ušpuras

Copyright © 2016 Wei Xu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The double-ended guillotine break (DEGB) of the horizontal coaxial gas duct accident is a serious air ingress accident of the high temperature gas-cooled reactor pebble-bed module (HTR-PM). Because the graphite is widely used as the structure material and the fuel element matrix of HTR-PM, the oxidation analyses of this severe air ingress accident have got enough attention in the safety analyses of the HTR-PM. The DEGB of the horizontal coaxial gas duct accident is calculated by using the TINTE code in this paper. The results show that the maximum local oxidation of the matrix graphite of spherical fuel elements in the core will firstly reach  mol/m3 at about 120 h, which means that only the outer 5 mm fuel-free zone of matrix graphite will be oxidized out. Even at 150 h, the maximum local weight loss ratio of the nuclear grade graphite in the bottom reflectors is only 0.26. Besides, there is enough time to carry out some countermeasures to stop the air ingress during several days. Therefore, the nuclear grade graphite of the bottom reflectors will not be fractured in the DEGB of the horizontal coaxial gas duct accident and the integrity of the HTR-PM can be guaranteed.