Radwaste, Thermal conductivity, density, porosity and mineralogy of core samples from Chalk River, Pinawa and Atikokan

Thermal conduction in a composite circular cylinder: a new technique for thermal conductivity measurements of lunar core samples

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1980.0004 ◽

1980 ◽

Vol 293 (1406) ◽

pp. 571-598 ◽

Cited By ~ 6

Keyword(s):

Thermal Conductivity ◽

Thermal Conduction ◽

Lunar Regolith ◽

Lunar Soil ◽

New Technique ◽

Conductivity Measurements ◽

Core Samples ◽

Present Technique ◽

A New Technique ◽

Lunar Core

A new technique has been developed for the measurement of the thermal conductivity of lunar core samples. According to this technique, the core sample is heated radiatively from the outside at a known rate, the temperature is measured at the surface of the coretube, and the thermal conductivity of the sample is determined by comparing the measured temperature with the theory. The technique conforms with the aims of lunar sample preservation in that the sample remains intact after the measurements. The solution, as obtained in this paper, of a thermal conduction equation for a composite circular cylinder, with zero initial temperature and a constant heat-flux at its outer boundary, provides a theoretical basis for the present technique. Because of their mathematical similarity, the corresponding problems for a composite slab or sphere were also solved and the solutions are presented for possible future application to the thermal conductivity measurements. Testing demonstrated the feasibility of the new technique. The thermal conductivity of a simulant lunar soil sample, as determined by the present technique under vacuum conditions at about 300 K for sample densities of 1.47-1.67 g cm -3 , is 2.05-2.65 x 10 -3 W m -1 K -1 , which compares favourably with that of the same sample, 1.61-2.89 x 10 -3 W m -1 K -1 at sample densities of 1.50-1.75 g cm -3 , as measured under similar conditions by the standard line heat source technique. We describe in detail the experimental apparatus construction and procedure; in particular, the number of precautions taken to preserve the samples from disturbances and to improve the measurement results. This technique was successfully applied to the thermal conductivity measurement of two Apollo 17 drill-core samples. The results, 1.9-4.9 x 10 -3 W m -1 K -1 , which is intermediate between the values of thermal conductivity of the lunar regolith determined in situ (0.9-1.3 x 10 -2 W m -1 K -1 and those of lunar soil samples measured in the laboratory under simulated lunar surface conditions (0.8-2.5 x 10 -3 W m -1 K -1 ) presents an important clue to the understanding of heat transportation mechanisms in the lunar regolith.

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Performance properties of vacuum insulation panels produced with various filling materials

Science and Engineering of Composite Materials ◽

10.1515/secm-2013-0162 ◽

2014 ◽

Vol 21 (4) ◽

pp. 521-527 ◽

Cited By ~ 3

Author(s):

Metin Davraz ◽

Hilmi C. Bayrakci

Keyword(s):

Thermal Conductivity ◽

Silicon Carbide ◽

Glass Fiber ◽

Fumed Silica ◽

Production Costs ◽

Unit Weight ◽

Insulation Material ◽

Core Samples ◽

Vacuum Insulation ◽

Precipitated Silica

AbstractVacuum insulation panel (VIP) is known to be the most effective insulation material. However, the usage areas of VIPs are restricted because of their high production costs. The core of VIP is the most important item affecting the cost of VIP. In this study, to obtain VIPs, which are provided with minimum thermal conductivity resistance value (R=5 m2 K/mW), was aimed for the optimal thickness of the panel (<40 mm). Therefore, 14 different core samples of VIP were produced by using various types of powders (fumed silica, precipitated silica, perlite, and diatomite), opacifiers (silicon carbide, carbon black, and titanium dioxide), and fibers (glass fiber, organic fiber, and cellulosic fiber). By using appropriate test methods, the physical properties of core samples such as unit weight, porosity, mass per volume and mechanical properties, their uniaxial compressive strength, tensile strength, and dimensional stability and also thermal conductivity coefficient in vacuum were determined. Results were compared with values of reference materials. The most appropriate compression pressure used in the manufacture of core sample was 27.5 kN. In addition, taking into account the benefit-cost relationship, the results of this study showed that the mix of fumed silica and precipitated silica (powder material), silicon carbide (opacifier), and glass fiber (fiber) was determined as the most suitable raw materials.

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Thermal conductivity of core samples from the Cerro Prieto geothermal field: Experimental results and an improved prediction method

Geothermics ◽

10.1016/0375-6505(80)90030-9 ◽

1980 ◽

Vol 9 (1-2) ◽

pp. 169-178 ◽

Cited By ~ 3

Author(s):

L.F. Martínez-Báez

Keyword(s):

Thermal Conductivity ◽

Prediction Method ◽

Geothermal Field ◽

Experimental Results ◽

Core Samples ◽

Cerro Prieto

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An Analysis of a Method of In-Situ Thermal Properties Determination for Geologic Formations

Journal of Energy Resources Technology ◽

10.1115/1.3231149 ◽

1985 ◽

Vol 107 (1) ◽

pp. 122-127

Author(s):

J. D. Lin ◽

T. J. Love

Keyword(s):

Thermal Conductivity ◽

Thermal Properties ◽

Moisture Content ◽

Oil Recovery ◽

Thermal Methods ◽

Core Samples ◽

Time Required ◽

And Storage ◽

Flux Probe

Geothermal investigations and thermal methods of oil recovery require the thermal properties of rock be known. The thermal conductivity of rock is normally determined by measuring the properties of core samples which have been removed from the well. The major problem with this is the fact that thermal properties are dependent on the moisture content of the rock. This moisture content is very likely altered in transportation and storage. This paper presents an analysis which serves as the basis of a transient heat flux probe measurement that may be used to determine the thermal conductivity and diffusivity in situ. Such in-situ measurements would overcome the disadvantages of core samples and may also be used when core samples are not available. This analysis also provides a method of estimating the time required in order to obtain valid results. The analysis indicates rather long test times may be required for accurate results. However, it does provide a basis for evaluating the results of measurements taken for shorter times. The effects of contact thermal resistance between the probe, the well casing, and the formation are evaluated.

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