Since the specific activity of uranium is very low, it is not easy to analyze numerous liquid samples containing a small amount of uranium, and it is effective to improve the operational efficiency by pre-screening the uranium using a simple method. We expect that the proposed method, wherein uranium in a liquid sample is adsorbed on graphene oxide, collected by a membrane filter and analyzed by X-ray fluorescence, is suitable for screening such a liquid sample containing uranium. However, graphene oxide comprises small particles that clog the membrane filter during collection. When sodium perchlorate is added to the sample, the salinity concentration increases and graphene oxide aggregates, rendering the filtration process easier. In this study, it was confirmed that the addition of sodium perchlorate to the sample shortened the graphene oxide collection time and did not affect the fluorescent X-ray analysis results. The lower limit of uranium detection by this method is approximately 0.42 ng mL^–1, which is equals to 0.042 mBq cm^–3 when converted to the radioactivity concentration under conservative conditions. This is approximately 1/500 of the effluent standard value for uranium in drainage water.

The Tokai Reprocessing Plant is the first reprocessing plant in Japan which started hot test in 1977, and had reprocessed 1,140 tons of spent nuclear fuel by May 2007. The gaseous and liquid radioactive wastes have been discharged to the environment. Since iodine-129 (¹²⁹I) is one of the most important nuclides for the long-term environmental impact assessment. Therefore, ¹²⁹I in the exhaust and effluent has been controlled, and precise analysis methods of ¹²⁹I in the environmental samples have been developed, and the concentrations of ¹²⁹I in the various environmental samples have been investigated. This report presents an overview of these activities. Not limited to ¹²⁹I on the reprocessing facilities, it is essential for nuclear operators to reduce the amount released to the environment in the spirit of ALARA, and to continuously develop the further upgrading environmental monitoring methods and evaluation methods in order to foster a sense of safety and security among residents living in the vicinity of the facilities.