Development of zeolite-based adsorbents for highly contaminated water in Fukushima

The Great East Japan Earthquake and Tsunami struck the Fukushima Daiichi Nuclear Plant in March 2011, which caused significant volume of high-level radiation contaminated water on the premises. Impurities such as magnesium and calcium in the contaminated brine water made conventional type of adsorbents difficult to thoroughly remove nuclides from the water. With the support of research institutions and customers, Union Showa K.K. successfully co-developed a series of high performance adsorbents with enhanced selectivity in the brine water such as adsorbent for cesium, simultaneously removing cesium and strontium, silver mounted zeolite for iodine removal and so on. These new adsorbents have contributed to the purification of contaminated water on the site. The company has also developed the method of stable solidification of cesium captured in ferrocyanide compound and the regenerative adsorbent for the Harbor Cleanup Project. The company now focuses on the development of adsorbent for removing actinide elements for fuel debris retrieval. (author)