Pore Structure of Matrix Graphite and Its Effect on Ag Diffusion

doi:10.11944/j.issn.1000-0518.2019.12.190106

Chinese Journal of Applied Chemistry ›› 2019, Vol. 36 ›› Issue (12): 1430-1438.DOI: 10.11944/j.issn.1000-0518.2019.12.190106

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Pore Structure of Matrix Graphite and Its Effect on Ag Diffusion

FAN Luhao,ZHANG Chi,JIAO Zengtong,HE Linfeng,QI Meili,XU Gang(),CHEN Xiaotong()

Institute of Nuclear and New Energy Technology,Collaborative Innovation Center of Advanced Nuclear Energy,Tsinghua University,Beijing 100084,China

Received:2019-04-16 Accepted:2019-06-25 Published:2019-12-01 Online:2019-12-10
Contact: XU Gang,CHEN Xiaotong

Abstract

Abstract:

As a high temperature gas cooled reactor fuel element, matrix graphite is a porous composite material that is a major component of the fuel element. The structure of matrix graphite affects the performance of the fuel element and the diffusion of fission products inside. In this paper, the pore structure of matrix graphite was characterized by mercury intrusion method, and the influences of the maximum pressing pressure in the preparation process and further heat treatment process on the pore structure of matrix graphite were discussed. The results show that the pore size of large pores in the matrix graphite is 6001900 nm. High-temperature heat treatment reduces the total porosity, the median pore diameter and the volume of large pores in the matrix graphite. The volume of large pores in the matrix graphite decreases linearly with the increase of the maximum pressing pressure in preparation process. Meanwhile, the diffusion rate of Ag in the graphite matrix has a positive correlation with the variation of the pore volume during high-temperature heat treatment.

Key words: matrix graphite, pore structure, mercury intrusion method, Ag diffusion

FAN Luhao, ZHANG Chi, JIAO Zengtong, HE Linfeng, QI Meili, XU Gang, CHEN Xiaotong. Pore Structure of Matrix Graphite and Its Effect on Ag Diffusion[J]. Chinese Journal of Applied Chemistry, 2019, 36(12): 1430-1438.

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Pore Structure of Matrix Graphite and Its Effect on Ag Diffusion

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