Gas-escape pores in nuclear graphite IG-110 and T220 were characterized by using optical microscopy. It is proved that reliable size distribution of pores can be derived by processing optical images of graphite. The results were compared with those obtained from mercury porosimetry test and X-ray tomography. Optical microscopy showed that the majority of IG-110's (T220's) porosity is contributed by pores with sizes around 13 (3) µm, which was confirmed by X-ray tomography for IG-110. But, mercury porosimetry test indicated that pores with sizes around 2.3 (0.9) µm contribute the majority of IG-110's (T220's) porosity. The difference between mercury porosimetry and the other two techniques suggests that the graphite pores are connected by relatively thinner channels.
FreemanHM, JonesAN, WardMB, On the nature of cracks and voids in nuclear graphite. Carbon. 2015;103:45–55. doi: 10.1016/j.carbon.2016.03.011
2.
BurchellTD, SneadLL.The effect of neutron irradiation damage on the properties of grade NBG-10 graphite. J Nucl Mater. 2007;371:18–27. doi: 10.1016/j.jnucmat.2007.05.021
3.
MarsdenBJ, HavertyM, BodelW, Dimensional change, irradiation creep and thermal/mechanical pro-perty changes in nuclear graphite. Int. Mater. Rev. 2016;61(3):155–182. doi: 10.1080/09506608.2015.1136460
4.
MarsdenBJ, HallGN, WoutersO, Dimensional and material property changes to irradiated Gilsocarbon graphite irradiated between 650 and 750°C. J Nucl Mater. 2008;381:62–67. doi: 10.1016/j.jnucmat.2008.07.018
5.
PaulRM, MorralJE.A 3D random pore model for oxidation of graphite with open porosity. J Nucl Mater. 2018;499:344–352. doi: 10.1016/j.jnucmat.2017.11.056
6.
HuangWH, TsaiSC, YangCW, The relationship between microstructure and oxidation effects of selected IG- and NBG-grade nuclear graphites. J Nucl Mater. 2014;454:149–158. doi: 10.1016/j.jnucmat.2014.07.052
7.
YangX, TsangDKL.Evaluating Young's modulus of porous nuclear graphite by a novel multi-scale method. J Mater Sci. 2017;52(18):10959–10971. doi: 10.1007/s10853-017-1259-3
8.
HodgkinsA, MarrowTJ, WoottonMR, Fracture behaviour of radiolytically oxidised reactor core graphites: a view. Mater Sci Technol. 2010;26(8):899–907. doi: 10.1179/026708309X12526555493477
9.
TangH, QiW, HeZ, Infiltration of graphite by molten 2LiF-BeF2 salt. J Mater Sci. 2017;52(19):11346–11359. doi: 10.1007/s10853-017-1310-4
10.
JingSP, ZhangC, PuJ, 3D microstructures of nuclear graphite: IG-110, NBG-18 and NG-CT-10. Nucl Sci Tech. 2016;27:66. doi: 10.1007/s41365-016-0071-0
PayneL, HeardPJ, ScottTB.A study of the oxidation behavior of Pile Grade A (PGA) nuclear graphite using thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and X-ray tomography (XRT). Plos One. 2015;10(11):0143041. doi: 10.1371/journal.pone.0143041
13.
BaboutL, MarsdenBJ, MummeryPM, Three-dimensional characterization and thermal property modelling of thermally oxidized nuclear graphite. Acta Mater. 2008;56(16):4242–4254. doi: 10.1016/j.actamat.2008.04.045
14.
HodgkinsA, MarrowTJ, MummeryP, X-ray tomography observation of crack propagation in nuclear graphite. Mater Sci Technol. 2006;22(9):1045–1051. doi: 10.1179/174328406X114126
15.
MoskovicR, FlewittPEJ, SchlangenE, Understanding fracture behaviour of PGA reactor core graphite: perspective. Mater Sci Technol. 2014;30(2):129–145. doi: 10.1179/1743284713Y.0000000354
16.
LiuD, FlewittPEJ.Deformation and fracture of carbonaceous materials using in situ micro-mechanical testing. Carbon. 2017;114:261–274. doi: 10.1016/j.carbon.2016.11.084
17.
KaneJ, KarthikC, ButtDP, Microstructural characterization and pore structure analysis of nuclear graphite. J Nucl Mater. 2011;415(2):189–197. doi: 10.1016/j.jnucmat.2011.05.053
18.
ContescuCI, GuldanT, WangP, The effect of microstructure on air oxidation resistance of nuclear graphite. Carbon. 2012;50(9):3354–3366. doi: 10.1016/j.carbon.2012.01.040
19.
TaylorJEL, HallGN, MummeryPM.Investigating the effects of stress on the pore structures of nuclear grade graphites. J Nucl Mater. 2016;470:216–228. doi: 10.1016/j.jnucmat.2015.12.031
20.
WangP, ContescuCI, YuS, Pore structure development in oxidized IG-110 nuclear graphite. J Nucl Mater. 2012;430:229–238. doi: 10.1016/j.jnucmat.2012.07.015
21.
León y LeónCA.New perspectives in mercury porosimetry. Adv Colloid Interfac. 1998;76–77:341–372. doi: 10.1016/S0001-8686(98)00052-9
22.
DiamondS.Mercury porosimetry An inappropriate method for the measurement of pore size distributions in cement-based materials. Cement Concrete Res. 2000;30(10):1517–1525. doi: 10.1016/S0008-8846(00)00370-7
