Graphite Testing for Nuclear Applications: The Significance of Test Specimen Volume and Geometry and the Statistical Significance of Test Specimen Population

Anisotropic thermal transport properties of quartz: from −120 °C through the <i>α</i>–<i>β</i> phase transition

“…After Hofmeister (2007), limiting the thickness-todiameter ratio to d/ø = 0.1 gives intrinsic thermal diffusivities without or at least negligible influence of mode mixing. In this study, all specimens exceed this ratio and have d/ø ∼ 0.2-0.5 (see Swank and Windes, 2014;ASTM E1461, 2013. As the results in this study show good agreement with the thermal diffusivity data of single-crystal quartz presented by, e.g.…”

“…Uncertainties can be higher in the vicinity of phase transitions, e.g. due to a pronounced distortion of the signal-time curves (overlap of different heat transport processes) or by using very small (McMasters et al, 2017) and/or thick sample dimensions (Swank and Windes, 2014).…”

“…Thermal transport properties such as thermal conductivity λ and thermal diffusivity D play an important role in understanding Earth's crust and mantle dynamics and their underlying processes (Čermák, 1982;Lenardic and Kaula, 1995). Furthermore, growing attention is given to a precise knowledge of heat transport in material sciences as well as in engineering (Taylor and Kelsic, 1986;Turner and Taylor, 1991). According to Fourier's law, the heat flux q is equal to the thermal conductivity λ of a material multiplied by the negative temperature gradient ∂T /∂x in one dimension:…”

Assessment of the fracture toughness of neutron-irradiated nuclear graphite by 3D analysis of the crack displacement field

“…The fracture resistance of nuclear graphite is generally obtained from large standardised specimens [25], and a challenge is presented by the difficulty of assessing small specimens of irradiated material that represent the state of the graphite in the core of a reactor. The motivation for the work reported in this paper is to investigate test specimens that might be used to measure the fracture resistance of small specimens of graphite that could be obtained from operating reactors cores [26,27] or materials test reactors [28]. One design that is suitable for small specimen tests of brittle materials is the double-cleavage drilled compression (DCDC) geometry [29] (Figure 1).…”