Experimental Approach for Study on Mechanism of Formation and Growth of Nanometer-Sized Cesium Compounds

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First, formation of nanometer-sized silver particles, which were one of the fission products, was systematically carried out as model particles of cesium compound particles mainly included in the fission products in a recycle process for nuclear fuel used in a light-water reactor. Although the values of the volumetric average diameter, DィイD2V, DMA ィエD2, obtained by our differential mobility analyzer under low pressure conditions ranging from 123 to 300 Torr developed in this study, were approximately 7% larger than those of the volumetric average diameter, DィイD2V, TEMィエD2, obtained from the transmission electron microscope (TEM) observation results of the silver particles collected at the DMA inlet, both the DMA and TEM size measurements were found to be in good agreement. The theoretical sizes calculated from the operation conditions for the DMA were also found to be in good agreement with those of DィイD2V, TEMィエD2 obtained from the TEM observation results of the silver particles colle … More cted after the classification by the DMA in the range from 6 to 25 nm, although the theoretical sizes set by the DMA were approximately 14% larger than those of DィイD2V, TEMィエD2 measured from the TEM observation results after the classification by the DMA.Second, the geometric standard deviations of the size distributions obtained from the TEM images after classification were found to range from 1.08 to 1.17, and they were approximately equal to the theoretical value (1.093) of the particles classified by the DMA, where as the geometric standard deviations of the size distributions obtained from the TEM images before the classification ranged from 1.34 to 1.50 and were greater than those after classification.Additionally, a generator for cesium iodide particles which consisted of typical fission products, namely cesium and iodine , was developed, and nanometer- sized cesium iodide particles were formed and their size distributions were measured by the DMA The particle size ranged from 5 to 100 nm (or larger) and was found to increase with an increase in the furnace temperature at the generator. The concentration of formed particles was slightly increased with the increase in the furnace temperature. We also demonstrated the validity of our DMA system for size measurements and the classification of the nm- sized cesium iodide particles as similar to the case s of silver particles. Less