MICROWAVE-OVEN DISSOLUTION OF GEOLOGICAL SAMPLES - NOVEL APPLICATION IN THE DETERMINATION OF NATURAL DECAY SERIES RADIONUCLIDES

A microwave oven was utilised to decompose several geological materials by means of acid digestion. Dissolution was achieved in 5 min and238U,234U,232Th and230Th were all determined on the solutions by radiochemical separation and α-spectrometry. The materials, which include a granite, an arkose, a river sediment and a nearshore marine sediment, display a large range in U and Th contents /Th/U ratio of 0.7 to 7: U content of 12 to 1400 Bq kg-1/ and activity ratios /234U/238U of 0.95 to 1.50/. The data indicate that the microwave oven dissolution method produces data comparable to the traditional /open beaker/ method. Unit costs are, however, significantly reduced. © 1990 Akadémiai Kiadó.