On the nature of cracks and voids in nuclear graphite

H. M. Freeman; A. N. Jones; M. B. Ward; F. S. Hage; N. Tzelepi; Q. M. Ramasse; A. J. Scott; R. M D Brydson

doi:10.1016/j.carbon.2016.03.011

On the nature of cracks and voids in nuclear graphite

H. M. Freeman^*, A. N. Jones, M. B. Ward, F. S. Hage, N. Tzelepi, Q. M. Ramasse, A. J. Scott, R. M D Brydson

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

Microcracks in neutron-irradiated nuclear grade graphite have been examined in detail for the first time using a combination of transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), energy dispersive X-ray (EDX), and energy filtered TEM (EFTEM). Filler particles from both unirradiated Pile Grade A (PGA) and three irradiated British Experimental Pile 'O' (BEPO) graphite specimens were investigated with received doses ranging from 0.4 to 1.44 displacements per atom (dpa) and an irradiation temperature of between 20 and 120 °C. We suggest that the concentration and potentially the size of microcracks increase with increasing neutron irradiation and show that disordered carbon material is present in a range of microcracks (of varying size and shape) in all specimens including unirradiated material. EFTEM and EELS data showed that these cracks contained carbon material of lower density and graphitic character than that of the surrounding bulk graphite. The presence of partially filled microcracks has potentially significant implications for the development of microstructural models for the prediction of radiation-induced dimensional and property changes in nuclear graphite.

Original language	English
Pages (from-to)	45-55
Number of pages	11
Journal	Carbon
Volume	103
DOIs	https://doi.org/10.1016/j.carbon.2016.03.011
Publication status	Published - 1 Jul 2016

Keywords

nuclear graphite
Crack closure
irradiation damage

Research Beacons, Institutes and Platforms

Energy
Advanced materials

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10.1016/j.carbon.2016.03.011

Cite this

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title = "On the nature of cracks and voids in nuclear graphite",

abstract = "Microcracks in neutron-irradiated nuclear grade graphite have been examined in detail for the first time using a combination of transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), energy dispersive X-ray (EDX), and energy filtered TEM (EFTEM). Filler particles from both unirradiated Pile Grade A (PGA) and three irradiated British Experimental Pile 'O' (BEPO) graphite specimens were investigated with received doses ranging from 0.4 to 1.44 displacements per atom (dpa) and an irradiation temperature of between 20 and 120 °C. We suggest that the concentration and potentially the size of microcracks increase with increasing neutron irradiation and show that disordered carbon material is present in a range of microcracks (of varying size and shape) in all specimens including unirradiated material. EFTEM and EELS data showed that these cracks contained carbon material of lower density and graphitic character than that of the surrounding bulk graphite. The presence of partially filled microcracks has potentially significant implications for the development of microstructural models for the prediction of radiation-induced dimensional and property changes in nuclear graphite.",

keywords = "nuclear graphite, Crack closure, irradiation damage",

author = "Freeman, {H. M.} and Jones, {A. N.} and Ward, {M. B.} and Hage, {F. S.} and N. Tzelepi and Ramasse, {Q. M.} and Scott, {A. J.} and Brydson, {R. M D}",

year = "2016",

month = jul,

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doi = "10.1016/j.carbon.2016.03.011",

language = "English",

volume = "103",

pages = "45--55",

journal = "Carbon",

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AU - Freeman, H. M.

AU - Jones, A. N.

AU - Ward, M. B.

AU - Hage, F. S.

AU - Tzelepi, N.

AU - Ramasse, Q. M.

AU - Scott, A. J.

AU - Brydson, R. M D

PY - 2016/7/1

Y1 - 2016/7/1

N2 - Microcracks in neutron-irradiated nuclear grade graphite have been examined in detail for the first time using a combination of transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), energy dispersive X-ray (EDX), and energy filtered TEM (EFTEM). Filler particles from both unirradiated Pile Grade A (PGA) and three irradiated British Experimental Pile 'O' (BEPO) graphite specimens were investigated with received doses ranging from 0.4 to 1.44 displacements per atom (dpa) and an irradiation temperature of between 20 and 120 °C. We suggest that the concentration and potentially the size of microcracks increase with increasing neutron irradiation and show that disordered carbon material is present in a range of microcracks (of varying size and shape) in all specimens including unirradiated material. EFTEM and EELS data showed that these cracks contained carbon material of lower density and graphitic character than that of the surrounding bulk graphite. The presence of partially filled microcracks has potentially significant implications for the development of microstructural models for the prediction of radiation-induced dimensional and property changes in nuclear graphite.

AB - Microcracks in neutron-irradiated nuclear grade graphite have been examined in detail for the first time using a combination of transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), energy dispersive X-ray (EDX), and energy filtered TEM (EFTEM). Filler particles from both unirradiated Pile Grade A (PGA) and three irradiated British Experimental Pile 'O' (BEPO) graphite specimens were investigated with received doses ranging from 0.4 to 1.44 displacements per atom (dpa) and an irradiation temperature of between 20 and 120 °C. We suggest that the concentration and potentially the size of microcracks increase with increasing neutron irradiation and show that disordered carbon material is present in a range of microcracks (of varying size and shape) in all specimens including unirradiated material. EFTEM and EELS data showed that these cracks contained carbon material of lower density and graphitic character than that of the surrounding bulk graphite. The presence of partially filled microcracks has potentially significant implications for the development of microstructural models for the prediction of radiation-induced dimensional and property changes in nuclear graphite.

KW - nuclear graphite

KW - Crack closure

KW - irradiation damage

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DO - 10.1016/j.carbon.2016.03.011

M3 - Article

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SN - 0008-6223

VL - 103

SP - 45

EP - 55

JO - Carbon

JF - Carbon

ER -

On the nature of cracks and voids in nuclear graphite

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FUNDAMENTALS OF CURRENT AND FUTURE USES OF NUCLEAR GRAPHITE

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On the nature of cracks and voids in nuclear graphite

Abstract

Keywords

Research Beacons, Institutes and Platforms

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FUNDAMENTALS OF CURRENT AND FUTURE USES OF NUCLEAR GRAPHITE

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