발간논문

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The rate of thermal dissociation of calcium hydride was measured under argon atmosphere using a thermogravimetric technique. The weight less curve were obtained for various conditions in temperature range of 790 C to 840 C, and the temperature dependence of dissociation rate was also determined. As variables, Hydrogen partial pressure, total flow rate and the shape of the sample holder were involved, their effects on the dissociation rate were discussed. The reaction mechanism was estimated comparing the experimental results with various reaction models assuming chemical reaction control at the interface, diffusion control in the products layer or gas film diffusion at surface, in each case the rate parameters for mass transfer was calculated. From the experimental results, the reaction was shown to be mainly controlled by surface gas film diffusion.

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Reaction rates of Zirconium with hydrogen was studied using thermal gravity analysis (TGA) method to investigated the reaction mechanism under the similar environments of atomic reactor core. The effects of temperature and hydrogen pressure on the rate was calculated. And found the rate controlling step of Zirconium-hydrogen reaction to be diffusion of hydrogen in Zirconium. The appropriate diffusion equation was solves and the diffusivities were calculated.

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In order to form β-Ti-H alloy and γ hydride, the movement of hydrogen in titanium have been studied, employing T. G. A. method. It has been found that 1) the reaction of Ti-hydride formation is controlled by hydrogen diffusion in Titanium. 2) the activation energy of the reaction is 4.6㎉/㏖. 3) Surface contamination of titanium metal retards the reaction markedly.

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