Analysis
Three Bentonite properties, which makes it a unique buffer material for nuclear disposal applications are discussed in the following:
1) Thermal conductivity
Thermal conductivity is the rate at which heat can be transferred through a certain material. It is also expressed as the flux of heat, which flows per unit time through a unit distance with a temperature gradient of one degree per unit area. Thermal conductivity, like other tensor parameters, has different values in different directions. In SI units, thermal conductivity has the unit of watts per meter Kelvin (W/ (m*K)).
Each HLW (or spent fuel) disposal canister produces around 1000 to 2000 watts of heat during the decay processes. In order to reduce the heat related mineral …show more content…
A temperature difference is created because of heat flow transferring through the material and the heat flow meter itself. Bentonite pellets are compacted in an insulated frame which has the following dimension: length and width of 450 millimetres and height of 80 millimetres. The frame is in the machine for 48 hours. [16]
b) Thermal probe method
In this method a heat source is inserted into the Bentonite pellet and energy is applied continuously at a constant rate. A thermal sensor is used to determine the thermal conductivity of the Bentonite pellet by analysing the temperature gradient change adjacent to the heat source. The Bentonite pellets are prepared by hand compaction in a plastic cylinder with a radius of 75 millimetres and a height of 200 millimetres, and the thermal probe is 160 millimetres long.The duration of the test is 30 minutes. [16]
b) Hot disk …show more content…
Changes in the temperature coefficient of resistivity correlate with corresponding temperatures. The heating time is related to the size of the sample, because the lateral boundaries will affect the specimen. In order to measure stable values of thermal conductivity, the sample size must be considered during the period which heating is
Three Bentonite properties, which makes it a unique buffer material for nuclear disposal applications are discussed in the following:
1) Thermal conductivity
Thermal conductivity is the rate at which heat can be transferred through a certain material. It is also expressed as the flux of heat, which flows per unit time through a unit distance with a temperature gradient of one degree per unit area. Thermal conductivity, like other tensor parameters, has different values in different directions. In SI units, thermal conductivity has the unit of watts per meter Kelvin (W/ (m*K)).
Each HLW (or spent fuel) disposal canister produces around 1000 to 2000 watts of heat during the decay processes. In order to reduce the heat related mineral …show more content…
A temperature difference is created because of heat flow transferring through the material and the heat flow meter itself. Bentonite pellets are compacted in an insulated frame which has the following dimension: length and width of 450 millimetres and height of 80 millimetres. The frame is in the machine for 48 hours. [16]
b) Thermal probe method
In this method a heat source is inserted into the Bentonite pellet and energy is applied continuously at a constant rate. A thermal sensor is used to determine the thermal conductivity of the Bentonite pellet by analysing the temperature gradient change adjacent to the heat source. The Bentonite pellets are prepared by hand compaction in a plastic cylinder with a radius of 75 millimetres and a height of 200 millimetres, and the thermal probe is 160 millimetres long.The duration of the test is 30 minutes. [16]
b) Hot disk …show more content…
Changes in the temperature coefficient of resistivity correlate with corresponding temperatures. The heating time is related to the size of the sample, because the lateral boundaries will affect the specimen. In order to measure stable values of thermal conductivity, the sample size must be considered during the period which heating is