Study On Preparation Process Of Fabrication Of Orthosilicate Pebbles By Melt Spraying Method

It were serious problems that human must be confronted with energy shortage and environmental pollution. Nuclear fusion energy would solve them which is a clean safety and reproducible energy. America and Soviet Union present project which have built International Thermonuclear Experimental Reactor (ITER) for bring about nuclear fusion energy of controlled and commercialization in the Geneva summit in1985. It is a largest and the most ambitions project of international scientific and technology cooperation and china took part in this project in2003. Test blanket module (TBM) has a major function for test the tritium production in ITER. Chinese helium cooled ceramic breeder (CH HCCB) test blanket module is a test module which is design for checking product tritium and energy capture of commercial fusion in ITER. Orthosilicate pebbles have advantages that are lithium of high content, low activating rate of neutron, easy load and unload, big superficial area, much gap of each pebbles, good gas permeability, convenient diffusion and release of tritium and so on. Consequently it is significant that people study preparation and nature of orthosilicate pebbles in environmentally and economic field.In this paper, silicon dioxide and lithium carbonate are raw materials which can be synthesize orthosilicate precursor by solid reaction method, then fabrication of orthosilicate pebbles by melt spraying method. It is important that purity of phase of orthosilicate pebbles more than98%, diameter of orthosilicate pebbles between0.8-1.2mm, density of orthosilicate pebbles more than90%, degree of spheroid of orthosilicate pebbles more than95%, impurity content of orthosilicate pebbles less than0.5%except oxygen silicon lithium and so on. X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal analysis (DSC-TG and DTA-TG) are used as test and characterization methods. The method of synthesis of orthosilicate precursor, the method of fabrication of orthosilicate pebbles, microstructure, diameter of orthosilicate pebbles, crushing strength of pebbles have been researched systematically. The whole process is divided into the following four parts:(1) Silicon dioxide and lithium carbonate were used as raw materials to synthesize orthosilicate precursor according to the solid state reaction. With different sintering temperatures, different mixture ratios and sintering times for law of synthesize orthosilicate precursor.(2) Orthosilicate precursor was pulverized for particles which were used to fabricate orthosilicate pebbles by melt spraying method. With different nitrogen pressure, different temperatures of melt, different drop height of melt for law of fabricate orthosilicate pebbles.(3) Orthosilicate pebbles were heat treated in furnace of vacuum tube. With different heat temperatures for law of crush load of different diameter of pebbles.(4) Make a comparison between melt spraying method, extrusion-spheronisation-sintering method, sol-gel technique, indirect wet method for information of phase, different and crush load and so on.By the above research obtain technological parameter of solid reaction method and influencing factors of melt spraying method. Besides heat treatment can improve crush load of orthosilicate pebbles. Orthosilicate pebbles fit the fill of TBM which was fabricated by melt spraying method.