Properties and microstructures of a matrix graphite for fuel elements of pebble-bed reactors after high temperature purification at different temperatures

ZHOU Xiang-wen; ZHANG Kai-hong; YANG Yang; WANG Lei; ZHANG Jie; LU Zhen-ming; LIU Bing; TANG Ya-ping

doi:10.1016/S1872-5805(21)60048-3

Volume 36 Issue 5

Sep. 2021

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Article Navigation > New Carbon Mater. > 2021 > 36(5): 987-994

ZHOU Xiang-wen, ZHANG Kai-hong, YANG Yang, WANG Lei, ZHANG Jie, LU Zhen-ming, LIU Bing, TANG Ya-ping. Properties and microstructures of a matrix graphite for fuel elements of pebble-bed reactors after high temperature purification at different temperatures. New Carbon Mater., 2021, 36(5): 987-994. doi: 10.1016/S1872-5805(21)60048-3

Citation:

ZHOU Xiang-wen, ZHANG Kai-hong, YANG Yang, WANG Lei, ZHANG Jie, LU Zhen-ming, LIU Bing, TANG Ya-ping. Properties and microstructures of a matrix graphite for fuel elements of pebble-bed reactors after high temperature purification at different temperatures. New Carbon Mater., 2021, 36(5): 987-994. doi: 10.1016/S1872-5805(21)60048-3

Citation:

ZHOU Xiang-wen, ZHANG Kai-hong, YANG Yang, WANG Lei, ZHANG Jie, LU Zhen-ming, LIU Bing, TANG Ya-ping. Properties and microstructures of a matrix graphite for fuel elements of pebble-bed reactors after high temperature purification at different temperatures. New Carbon Mater., 2021, 36(5): 987-994. doi: 10.1016/S1872-5805(21)60048-3

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Properties and microstructures of a matrix graphite for fuel elements of pebble-bed reactors after high temperature purification at different temperatures

doi: 10.1016/S1872-5805(21)60048-3

Key Laboratory of Advanced Reactor Engineering and Safety, Ministry of Education, Institute of Nuclear and New Energy Technology of Tsinghua University, Beijing 100084 China

Funds: Chinese National S&T Major Project (ZX06901); Key R & D plan of Shandong Province (major scientific and technological innovation project，2020CXGC010306)

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Corresponding author: ZHOU Xiang-wen, Associate Research Fellow. E-mail: xiangwen@tsinghua.edu.cn
Received Date: 2020-04-14
Rev Recd Date: 2020-06-03

Available Online: 2021-03-16

Publish Date: 2021-10-01

Abstract

Abstract

The matrix graphite (MG) of pebble fuel elements for a High Temperature Gas-cooled Reactor (HTGR), composed of 71wt% natural graphite, 18 wt% artificial graphite and 11 wt% phenolic resin-derived carbon, was purified by high temperature treatment (HTT), and its properties and microstructure were analyzed to investigate the effect of different HTT temperatures and optimize the purification temperature. Results showed that with increasing HTT temperature, its density and thermal conductivity gradually increased, but pore size and d₀₀₂ gradually decreased. The rate of erosion caused by friction as the fuel pebbles move in the reactor also decreased. The ash content decreased significantly from to 18.2 to 12.3×10⁻⁶ after HTT at 1 600 ℃, but changed little when the HTT temperature was further increased to 1 900 ℃, especially for catalytic metals such as Fe, Ni and Ca that are related to its corrosion rate. The microstructure improvement and ash content reduction at high temperatures jointly contributed to the increase in the anti-corrosion performance of MG. Based on properties such as crushing strength, erosion resistance, and corrosion rate, a HTT of 1 600 ℃ is adequate although the MG gradually became more ordered with a further increase of HTT temperature from 1 600 to 1 900 ℃. This determination of an appropriate HTT temperature for the production of MG for the fuel elements of an HTGR should improve the production efficiency and reduce the mass production cost of this material for a commercial HTGR.
- A3-3 matrix graphite,
- Thermal conductivity,
- Corrosion rate,
- High temperature purification,
- Ash content

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References(12)

References

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