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内容記述 |
Inorganic materials, such as concrete used in many fusion reactor facilities, adsorb tritiated water, which makes decontamination difficult and causes the generation of a large amount of nonflammable radioactive waste. Water strongly adsorbed by surface with inorganic materials causes tritiated water to be adsorbed more strongly than light water as an isotope effect, resulting in the accumulation of tritium within inorganic materials. In response to this well-known phenomenon, we found that the composition-controlled titanate, an inorganic material, can selectively inhibit the adsorption of tritiated water onto the material, a characteristic that is the exact opposite of common knowledge. Focusing on "layered titanate," a general-purpose inorganic material that can be given various characteristics by controlling its shape and composition, we examined adsorption properties of tritiated water on the material experimentally by the method of indirectly contacting inorganic materials with tritiated water as vapor in an airtight container. Molecular sieve as an inorganic material that selectively adsorbs tritium concentrates tritiated water within itself, resulting in a lower concentration of tritiated water in the container. In contrast, it was found that titanate with composition control showed the exact opposite tendency of tritiated water concentration. This result is considered as a selective inhibition of tritiated water adsorption on the material. It was shown that it is possible to control the composition of titanate to selectively inhibit the adsorption of tritiated water onto materials based on a new concept. |
