MONITORING OF ENVIRONMENTAL RADIATION ON THE SPRATLY ISLETS IN THE SOUTH CHINA SEA

The concentration of radionuclides in environmental samples and the en vironmental radiation level (including cosmic rays) was monitored on S pratly Islets in South China Sea prior to the commercial operation of nearby Chinese nuclear power plants. Samples of coral sand, sea food v egetation, water, and accumulated fallout on the islet were obtained a nd measured for radioactivity. Except for some exposure originating fr om minute amounts of Co-60 and Cs-137, the radiation background is mai nly emitted from naturally occurring radionuclides. Radiation levels i ncluding beta, gamma, and neutron on the islet have also monitored. Ga mma dose rates for outdoor exposure averaged approximately 0.09 mu Sv/ h; the neutron dose rate was about 0.003 mu Sv/h. Automatic radiation surveillance and a routine sampling program on the Spratly Islets are viewed as essential to provide an early warning in the Far East in cas e of a nuclear emergency.