AMS MEASUREMENT OF ENVIRONMENTAL U-236 PRELIMINARY-RESULTS AND PERSPECTIVES

U-236 is a 23.4 Ma half-life radioactive isotope whose natural global abundance is expected to be overwhelmed in many places by its producti on and release during nuclear power generation. The detection of exces s U-236 in the environment is therefore a method of monitoring the pre sence of activated uranium. However, U-236 has not been widely used fo r environmental studies due to the difficulties of measuring it at low levels with standard cu-spectrometry or thermal ionization mass spect rometry. In principle, accelerator mass spectrometry can overcome some of the difficulties encountered in the traditional methods, making it possible to detect U-236 at very low levels so that a large range of environmental samples can be analyzed. In this paper, we report some p reliminary results of the U-236 measurements of four water samples fro m the US Idaho Chemical Processing Plant. Limitations with our current AMS system and the perspectives for considerable improvements will be discussed.