RADIUM, URANIUM AND THORIUM CONCENTRATIONS IN LOW SPECIFIC ACTIVITY SCALES AND IN WATERS OF SOME OIL AND GAS-PRODUCTION PLANTS

Low specific activity scales consisting of alkaline earth metal carbon ates and sulfates are often present in some gaseous and liquid hydroca rbon plants; these scales contain a certain concentration of radium, u ranium and thorium, which can cause a risk of gamma-irradiation and of internal radiocontamination when they must be mechanically removed. T hat being stated, U-235, Th-232 and Ra-226 were determined in scales, sludges and waters coming from different plants. U-238 and Th-232 conc entrations were found very low; the isotopes U-238 and U-234 resulted in radioactive equilibrium, whilst Th-232 and Th-228 were not always i n equilibrium. Ra-226 concentration was higher in scales and sludges t han in waters.