抄録
Exchange reaction of tritiated hydrogen to water vapor under the condition of tritium gas concentration between 1μCi/l and 1mCi/l was studied. Tritium gas with hydrogen gas of 5 Torr and water of 20mg were enclosed in a Pyrex glass ampule with volume of about 100ml. The mixed gas with water vapor was heated with electric furnace. The heating time was between 2 and 100hr, and the temperature was 776, 725, 675, 621, and 570.5°K. After heating, tritiated water was trapped with liquid nitrogen, and counted with a liquid scintillation counter. The radioactive concentration of initial tritiated hydrogen was measured with a calibrated ionization chamber. The main results obtained are as follows; 1) the concentration of produced tritiated water is well proportioned to that of initial tritiated hydrogen, 2) the activation energy of exchange reaction from tritiated hydrogen to tritiated water is 26.2kcal/mol and that of inverse reaction is 27.4kcal/mol, 3) the reaction rate at room temperature which calculated with activation energy is 1.04×10-13day-1, and then exchange reaction at room temperature is negligible.
