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Power Connectors
Published in Paul G. Slade, Electrical Contacts, 2017
Most switchgear is installed in relatively clean air with normal humidity. In such cases, lubrication of the silver-plated joints will seal the joints adequately and protect them against the entrance of an electrolyte and the possibility of galvanic corrosion. Some manufacturers use lubrication as a regular practice while others use high temperature wax, such as ceresin wax, dissolved in naphtha, which is easily applied to coat the silver-coated contact surfaces. In outdoor seacoast exposures and in other strongly corrosive atmospheres where galvanic corrosion prevails, inhibitor paints should be used in addition to the contact aid compounds or wax coating. The problem of porosity and excessive wear of silver-plated contacts during make and break operations, as in the type of disconnect switches, can be limited and practically eliminated by welding thin solid silver plates or strips to the copper or aluminum contact blades or jaws [154]. The welded solid silver contact interfaces are impervious to the creep or pore corrosion, less susceptible to fretting, have superior wear resistance and are significantly less affected by the sulfur-bearing environment since, as shown by Kassman-Rudolphi [155] the presence of tarnish films can have a beneficial effect on the contact behavior. Put differently, an appropriate combination of silver and sulfurized film properties can have positive effects on the wear and deformation of the contact and thus outweigh the negative effects of tarnishing on the electrical behavior of contact systems where sliding, fretting and make-and-brake actions are taken.
New Technologies of Liquid Radioactive Waste Conditioning
Published in Fusion Science and Technology, 2020
N. T. Kazakovsky, V. A. Korolev, A. A. Yukhimchuk
Tritium in organic liquids can be in a bound state, and its recovery is difficult. The main method of organic LRW reprocessing is burning, for which special installations are required. For safe storage and transportation of that LRW in laboratory conditions, we propose a solidification method.3 Thus, LRW is mixed with a saturated hydrocarbon mixture: paraffin, stearic acid, and ceresin wax. After transition into a liquid state at 70°С temperature, this hardener mixes well with vacuum oil and other organic substances, and after solidification, it forms a solid, homogeneous, hydrophobic compound, which guarantees safe storage. The final compound filling is 60% from mass. We can use this mixture for solidification of black oil and organic solvents (solvent, xylene, kerosene, White spirit, gasoline). To provide full safety and to reduce LRW handling time in a laboratory, we use a metallic container with a previously prepared hardener, and LRW is added by portions as far as it is produced. After a new portion of LRW is added to the container, it is heated up to 70ºС to melt down the content, and then it is cooled down. Further, the container with solidified radioactive waste can be stored safely for the staff and environment for a long time. We can add LRW portions up to the full saturation of the hardener mixture, which is controlled by measurement of the container mass with the final compound.