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This presentation focusses on the thermal test of a typical storage container design for the German final storage repository KONRAD. The preparation of the container, the conduction of the fire test itself and results like the temperature evolution and as-sumptions for thermal material properties are shown.
As thermal test final storage containers have to be exposed to a fire of 800 °C (1472 °F) for 1 hour according to the final storage conditions provided by the federal com-pany for radioactive waste disposal (BGE). The here discussed cask contains a steel covered concrete layer of a thickness of 100/150 mm. Heating up concrete is a highly nonlinear process since the vaporization of residual water consumes high amounts of thermal energy and produce vast amounts of steam.
The constantly measured temperatures provide the basis to adjust common models of thermal properties for concrete esp. for FEAs. Finally in a later step this will allow predictions of similar designed container with different sizes.
Today glass is broadly used in modern architecture. For applications indoor it is possible to produce decor glass by using enamel colors and glass painting techniques without any problems. However, this is more limited for applications outdoor. Humidity and environmental pollution attack the surface of the coating and damage it strongly. There are only few colors on the market which are resistant towards acids and bases until now. Additionally, most of those colors are opaque. In order to extend the color palette, chemically resistant colored glasses are being developed which are transparent, relatively low melting and intensively toned even in thin coat thickness. To achieve such ambitious aim, many parameters have to match which act in complex manner. Metal oxides were used to color the glasses. A lead-free glass composition was developed to avoid an exposition of heavy metals to the environment. The glasses were characterized, in particular in terms of their thermal properties, their crystallization and corrosion behavior as well as their chemical and environmental durability. Different practical applications will be shown.
To reduce the emission of CO2, liquified natural gas (LNG) is used as fuel. As the pipeline network is not developed all around the globe, LNG needs to be transported via ship or truck. Double-walled tanks made of steel with a vacuum insulation are currently used to keep LNG at cryogenic temperatures (-162 °C; 111 K). The double-walled construction makes the tanks heavy and expensive. Furthermore, there are some restriction to carry out in-service inspection using a double-wall design. Main topics: Lightweight design, superior thermal properties of GRP compared to steel Aim of this project is to develop a single-walled tank made of glass-fiber reinforced plastic (GRP) and an insulator, so that the tank pressure will not exceed 5 bar within a certain time, relative, as a result of the rising fluid temperature. First, the thermal and mechanical properties of GRP and the insulator at cryogenic temperatures must be determined. Liquid nitrogen (-196 °C; 77 K) is used for all experiments at cryogenic temperatures for safety reasons. Mechanical properties are analyzed by performing 3-point bending tests on cooled specimen. The tests show, that there are now significant changes on the mechanical properties of GRP, so that this material can be used in a cryogenic environment. To examine the thermal conductivity of GRP, a test rig is designed, in which one side of a GRP-laminate plate is cooled down while the other side is at room temperature at the beginning. Temperature is measured on both sides of the plate as well as inside the laminate. The temperature curves are then implemented in a ANSYS simulation to calculate thermal material properties. The experiments show, that the thermal conductivity of GRP is much lower than the one of steel, but still not low enough to design a single walled tank without an additional insulation. Therefore, a closed GRP pipe with insolation inside is immersed in liquid nitrogen for a defined time. Sensors record the surface temperatures inside and outside the specimen, as well as between insulation and GRP. With the data gained in this experiment, another ANSYS model is done. For correct simulation of the heat transfer between insulation and liquid nitrogen (or LNG later), a fluid simulation is necessary, which simulates the phase change from liquid to gaseous nitrogen. After validation of the model, a parameter study in the material properties of the insulation is performed, until a satisfying setup is achieved.