In routine surveillance operations, the radionuclide measurement of air discharged from an operating nuclear facility involves the entrainment of radionuclides on selective filter or absorptive media, and the determination of their gross beta activity. However, a more sensitive technique is required when specific analysis is desired for valid assessment of environmental radiation exposure, particularly when the gross beta activity levels are below 100 fCi/m3. For measuring environmental levels of 106Ru in air samples on glass fiber filters, a radiochemical procedure has been developed, tested and evaluated. The method which involves digestion,. distillation, and precipitation to separate and purify the radioruthenium has been employed in the analysis of air samples over the past year and a half. The method has been subsequently modified so that ruthenium, strontium and cesium can be measured sequentially on a single air filter. Minimum detection limits (3theta counting error) have averaged <0.02 fCi/m3 for 106Ru and <0.01 fCi/m3 for 137Cs and 89/90Sr; chemical yields have been 75, 80 and 75 %, respectively.
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