Determination of a porosity correction factor for the thermal conductivity of irradiated U02 fuel by means of the finite element method

Bakker, K.; Kwast, H.; Cordfunke, E.H.P.

doi:10.1016/0022-3115(95)00087-9

Cited by 38 publications

(22 citation statements)

References 7 publications

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“…Since b40, it is obvious that this equation always has a positive solution for l 3D . This equation may be transformed into a depressed cubic equation 4 and solved directly, but the depressed cubic solutions are unwieldy and so it is probably just as convenient to calculate l 3D numerically. Fig.…”

Section: D Sectionmentioning

confidence: 99%

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Thermal conductivity estimates of intumescent chars by direct numerical simulation

Staggs

2010

Fire Safety Journal

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Section: D Sectionmentioning

confidence: 99%

“…The goal is to provide an estimate of the 3D ETC from a digital image of a 2D section. This idea is not new and there have been [4][5][6]. Indeed, the author considered a similar problem using 3D arrays of thermal resistors [7].…”

Section: Introductionmentioning

confidence: 96%

Thermal conductivity estimates of intumescent chars by direct numerical simulation

Staggs

2010

Fire Safety Journal

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“…Kaempf equation [19] and Schulz equation [20] are taking into account the shape effect of the dispersed phase, and Bakker et al [21] examined the Schulz model to the irradiated fuel thermal conductivity and proved the good approximation for the correction of the dispersed porosity in the fuel matrix. Therefore, we applied Schulz model to our calculation for the thermal conductivity of the quasi-two phase MOX fuel.…”

Section: Calculation Modelmentioning

confidence: 99%

Thermal conductivity degradation analyses of LWR MOX fuel by the quasi-two phase material model

Kosaka

Kurematsu²,

Kitagawa³

et al. 2012

Journal of Nuclear Science and Technology

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The temperature measurements of mixed oxide (MOX) and UO 2 fuels during irradiation suggested that the thermal conductivity degradation rate of the MOX fuel with burnup should be slower than that of the UO 2 fuel. In order to explain the difference of the degradation rates, the quasi-two phase material model is proposed to assess the thermal conductivity degradation of the MIMAS MOX fuel, which takes into account the Pu agglomerate distributions in the MOX fuel matrix as fabricated. As a result, the quasi-two phase model calculation shows the gradual increase of the difference with burnup and may expect more than 10% higher thermal conductivity values around 75 GWd/t. While these results are not fully suitable for thermal conductivity degradation models implemented by some industrial fuel manufacturers, they are consistent with the results from the irradiation tests and indicate that the inhomogeneity of Pu content in the MOX fuel can be one of the major reasons for the moderation of the thermal conductivity degradation of the MOX fuel.

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“…A similar approach has been used in previous publications to investigate the thermal conductivity of computer-generated microstructures. 5,11,[22][23][24][25][26] In addition, Teague et al 6 created 2D meshes from various irradiated microstructures and employed this approach to calculate their thermal conductivity. Previous work has clearly shown that 2D simulations underpredict the impact of secondary particles on thermal conductivity, 23 so Teague et al 6 used conversion equations to convert the 2D results to 3D.…”

Section: Estimation Of the Effective Thermal Conductivity Using Simulmentioning

confidence: 99%

Using Coupled Mesoscale Experiments and Simulations to Investigate High Burn-Up Oxide Fuel Thermal Conductivity

Teague

Fromm

Tonks

et al. 2014

JOM

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Nuclear energy is a mature technology with a small carbon footprint. However, work is needed to make current reactor technology more accident tolerant and to allow reactor fuel to be burned in a reactor for longer periods of time. Optimizing the reactor fuel performance is essentially a materials science problem. The current understanding of fuel microstructure have been limited by the difficulty in studying the structure and chemistry of irradiated fuel samples at the mesoscale. Here, we take advantage of recent advances in experimental capabilities to characterize the microstructure in 3D of irradiated mixed oxide (MOX) fuel taken from two radial positions in the fuel pellet. We also reconstruct these microstructures using Idaho National Laboratory's MARMOT code and calculate the impact of microstructure heterogeneities on the effective thermal conductivity using mesoscale heat conduction simulations. The thermal conductivities of both samples are higher than the bulk MOX thermal conductivity because of the formation of metallic precipitates and because we do not currently consider phonon scattering due to defects smaller than the experimental resolution. We also used the results to investigate the accuracy of simple thermal conductivity approximations and equations to convert 2D thermal conductivities to 3D. It was found that these approximations struggle to predict the complex thermal transport interactions between metal precipitates and voids.

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Determination of a porosity correction factor for the thermal conductivity of irradiated U02 fuel by means of the finite element method

Cited by 38 publications

References 7 publications

Thermal conductivity estimates of intumescent chars by direct numerical simulation

Thermal conductivity estimates of intumescent chars by direct numerical simulation

Thermal conductivity degradation analyses of LWR MOX fuel by the quasi-two phase material model

Using Coupled Mesoscale Experiments and Simulations to Investigate High Burn-Up Oxide Fuel Thermal Conductivity

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