ULTRASONICS FOR RADIOACTIVE DECONTAMINATION

Tests have been run to determine in a preliminary fashion whether ultrasonic vibration would be effective in removing mixed radioactive deposits from the inside surface of steel pipes in a heat exchanger. Different frequencies (20 KC/S, l000 KC/S) have been used at the maximum power levels conveniently attainable. Different liquids were compared for cleaning effectiveness, with and without ultrasonics. Mild stirring of water bath at room temperature produced virtually no cleaning effect on the samples. Ultrasonics in water, at room temperature, gave 50% to 80% cleaning (as defined by gamma ray count) in 15 minutes or less. Certain chemical solutions gave moderate cleaning results without ultrasonics; but the effectiveness of these solutions was greatly enhanced by the addition of ultrasonics. It was found, as expected, that the effectiveness of the sound wave depended rather critically on the method of coupling to the work. (auth