Abstract: DIRECT ASSAY OF ~(90)Sr-~(90)Y IN LIQUID RADIOWASTE BY CERENKOV COUNTINGLI DAMING; GUO JINGRU; ZHANG SHULAN; CUI ANZHI; LIU DAMING（China Institute of Atomic Energy，P，O，Box 275（26）,Beijing 102413）ABSTRACT A direct method is developed to assay~(90)Sr-~(90)Y in liquid radiowaste samples by Cerenkovcounting without any chemical separation. Since the most interfering nuclides existing in liquid ra-diowaste have pcor counting efficiencies，their Cerenkov contribution can be corrected by HPGeγ-spectrometry. The ~(90)Sr-~(90)Y contens are determined for 10 kinds of liquid radiowaste samplesand radiochemically analyzed for comparison. The results show that this method is competent formost liquid radiowaste samples.Key words Liquid radiowaste ~(90)Sr-~(90)Y Cerenkov counting