Development of tritiated vapor absorbent applicable to the atmospheric detritiation system in a nuclear facility

Iwai, Yasunori; Yamanishi, Toshihiko

The combination of hydrogen oxidation reactor and water vapor absorber has been applied to the atmospheric detritiation system of tritium handling facility. Application of CaY faujasite-type zeolite to the adsorbent was investigated. The dehydration behavior was significantly improved using CaY zeolite with a high framework silica-to-alumina ratio. In contrast, detritiation factor for a CaY zeolite depended on the space velocity through the absorber. To apply a CaY zeolite to the ADS absorbent, the space velocity less than 250 h was recommended to maintain the detritiation factor more than 1000. The steep increase in water adsorption at the relative pressure lower than 0.05 is a feature of synthetic zeolite with calcium-cation. However, such an increase was not observed in the water adsorption on CaY zeolite with a framework SiO/AlO ratio more than 7.0. Consequently, the CaY zeolite with the framework SiO/AlO ratio of 5.0 is a promising candidate for absorbent of ADS absorber.