Research on the current status and development direction of Japan’s nuclear contamination water treatment technology based on patent analysis

Based on the patent data retrieved from the Incopat database, aims to clarify the research and development (R&D) characteristics in the field of nuclear-contaminated water treatment by Japanese research entities following the Fukushima nuclear accident. The results show as follows: After the Fukushima nuclear accident, the number of patent applications for nuclear-contaminated water treatment by Japanese research entities increased in a spurt. The treatment process is primarily dominated by the adsorption method. The core innovations focus on the preparation and modification of adsorbents. Before 2015, adsorbents containing ion-exchange reagents dominated patent applications. However, after 2015, inorganic adsorbents based on "silica, silicates, or titanates" gradually became the mainstream technology, with silicate-based adsorbents attracting significant attention due to their effective adsorption of cesium (Cs). As the primary operator of the Fukushima nuclear power plant, Tokyo Electric Power Company also focused on adsorption methods, without showing significant exploration of other treatment processes. Based on the analysis of patent literature from 2011 to 2025, it is recommended that researchers strengthen the optimization of adsorption processes and further investigate the impact of discharged nuclear-contaminated water on marine environments, and also looks forward to the exploration of better treatment processes for nuclear-contaminated water.