2019 Volume 73 Issue 1 Pages 413-420
Disposal of radioactive waste is a problem for the decommissioning of the Fukushima No.1 nuclear power plant. Cesium adsorbed zeolite is a secondary waste generated in the process of treatment of radioactively contaminated water. A disposal method of cesium adsorbed zeolite has not been established and is urgent. The cement solidification technology is superior to other solidifying methods in terms of the manufacturability and economic efficiency of the solidified product. These advantages are very important because a large amount of cesium adsorbed zeolite to be solidified is generated. In addition, cement solidification technology is referred to as a option for the disposal method of the cesium-adsorbed zeolite, as it has a proven method of low-level radioactive waste disposal in the past. The purpose of this study is to contribute to the feasibility evaluation of cement solidification technology of cesium adsorbed zeolite. Some studies have been conducted on the evaluation of the physical properties of cement-based materials using zeolite as a mixed material. However, there have been few studies aimed at solidifying zeolite. Therefore, in this study, the volume reduction efficiency and strength property of cement solidified product mixed with zeolite were examined by the compressive strength test and the flow test. As a result, it was confirmed that the cement solidified product can secure 1.5N/mm2 or more, which is an indicator of stability against falling and stacking of cement solidified product. Moreover, it was confirmed that the mix proportion in which the zeolite occupies half volume of the cement solidified product has sufficient required fresh property and strength property even in an environment simulating heat generation due to decay heat.
