Dimensional and material property changes to irradiated Gilsocarbon graphite irradiated between 650 and 750°C

Marsden, Barry; Hall, Graham; Wouters, O.; Vreeling, J.A.; Laan, J. van der

doi:10.1016/j.jnucmat.2008.07.018

Cited by 35 publications

(20 citation statements)

References 8 publications

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“…As illustrated in Fig.1a, Displacement Per Atom (DPA) levels peak at a depth of around 17.5 nm. Dimensional change in graphite is known to be related to the DPA [1,[9][10][11][12] and will therefore vary in a similar manner as a function of sample depth. Fig.…”

Section: Damage Profile Of 60 Kev Xe + Ions In Graphitementioning

confidence: 99%

See 1 more Smart Citation

Dynamic microstructural evolution of graphite under displacing irradiation

Hinks

Haigh

Greaves

et al. 2014

Carbon

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Section: Damage Profile Of 60 Kev Xe + Ions In Graphitementioning

confidence: 99%

“…in the basal planes) and an expansion in the c-direction (i.e. normal to the basal planes) [9][10][11][12][13]. The atomistic mechanisms which give rise to these changes are the subject of debate and the focus of considerable on-going scientific research [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Dynamic microstructural evolution of graphite under displacing irradiation

Hinks

Haigh

Greaves

et al. 2014

Carbon

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“…A study by Marsden et al 5 showed that their measured data compared well with the values predicted by Tsang's linear relationship. Thus, Equation (2-1) is adopted for the CTE calculation.…”

Section: Modeling Of Dimensional Changes Of Graphite Blocksmentioning

confidence: 65%

Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor

Schultz¹

2012

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SUMMARYCore bypass flow has been one of key issues in the very high temperature reactor (VHTR) design for securing core thermal margins and achieving target temperatures at the core exit. The bypass flow in a prismatic VHTR core occurs through the control element holes and the radial and axial gaps between the graphite blocks for manufacturing and refueling tolerances. These gaps vary with the core life cycles because of the irradiation swelling/shrinkage characteristic of the graphite blocks such as fuel and reflector blocks, which are main components of a core's structure. Thus, the core bypass flow occurs in a complicated multidimensional way. The accurate prediction of this bypass flow and counter-measures to minimize it are thus of major importance in assuring core thermal margins and securing higher core efficiency. Even with this importance, there has not been much effort in quantifying and accurately modeling the effect of the core bypass flow.The main objectives of this project were to generate experimental data for validating the software to be used to calculate the bypass flow in a prismatic VHTR core, validate thermofluid analysis tools and their model improvements, and identify and assess measures for reducing the bypass flow. To achieve these objectives, tasks were defined to (1) design and construct experiments to generate validation data for software analysis tools, (2) determine the experimental conditions and define the measurement requirements and techniques, (3) generate and analyze the experimental data, (4) validate and improve the thermofluid analysis tools, and (5) identify measures to control the bypass flow and assess its performance in the experiment. Design and construction of experimental facilities:The experimental designs, which consist of the air test led by the Korean Atomic Energy Institute (KAERI) at Seoul National University (SNU) and the matched-index-of-refraction (MIR) and air tests led by Idaho National Laboratory (INL) at Texas A&M University (TAMU), were completed in FY 2008. The air tests use air as a working fluid to obtain data for the validation of core thermofluid analysis codes; the MIR experiments are designed to produce data for the validation of computational fluid dynamics (CFD) codes. Based on the experimental designs, the construction of the multiblock air test facility and the MIR test facility were completed in FY 2009. A considerable portion of the experimental design efforts were directed at precisely controlling the bypass gap sizes and also the laser diagnostics designed to produce the validation data. Determination of experimental conditions and development of measurement techniques:A methodology for estimating gap size distribution in the prismatic cores was developed by KAERI in FY 2008 and applied to a reference prismatic core. The results were used in selecting the gap size and distribution in the test matrix. The influence of core restraint mechanism and replacement of side reflector on bypass gap distribution and hot spot fuel temperature was inv...

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“…Bulk dimensional change of Gilsocarbon graphite irradiated between 3 and 10 dpa at 650e750 C by Marsden et al and PCEA and PCIB irradiated between 6 and 10 dpa at 750 C by Vreeling et al found higher levels of shrinkage in the with-grain direction (parallel to the extrusion direction) than the against-grain direction [32,33]. For the specimens in this paper this is also the case, however higher dose PCEA6.8 shows a more significant crystallite size reduction in the against grain direction, suggesting it is near turnaround, as proposed previously.…”

Section: Xrdmentioning

confidence: 97%

Micro to nanostructural observations in neutron irradiated nuclear graphites PCEA and PCIB

Freeman

Mironov

Windes

et al. 2017

Journal of Nuclear Materials

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a b s t r a c tThe neutron irradiation-induced structural changes in nuclear grade graphites PCEA and PCIB were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED) and electron energy loss spectroscopy (EELS). The graphite samples were irradiated at the Advanced Test Reactor at the Idaho National Laboratory. Received doses ranged from 1.5 to 6.8 displacements per atom and irradiation temperatures varied between 350 C and 670 C.XRD and Raman measurements provided evidence for irradiation induced crystallite fragmentation, with crystallite sizes reduced by 39e55%. Analysis of TEM images was used to quantify fringe length, tortuosity, and relative misorientation of planes, and indicated that neutron irradiation induced basal plane fragmentation and curvature. EELS was used to quantify the proportion of sp 2 bonding and specimen density; a slight reduction in planar-sp 2 content (due to the buckling basal planes and the introduction of non-six-membered rings) agreed with the observations from TEM.

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Dimensional and material property changes to irradiated Gilsocarbon graphite irradiated between 650 and 750°C

Cited by 35 publications

References 8 publications

Dynamic microstructural evolution of graphite under displacing irradiation

Dynamic microstructural evolution of graphite under displacing irradiation

Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor

Micro to nanostructural observations in neutron irradiated nuclear graphites PCEA and PCIB

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