Development of a new generation of portable beta-gamma radiation survey instruments and application of the “as low as practicable” philosophy has presented a problem of compliance with guides far radioactive contamination control. Isolated, low-level, discrete particle beta-gamma contamination is being detected with the new instruments. In order to determine the limits of practicability, it is necessary to determine the limits of detection of these surface contaminants. The included data and calculations indicate typical source detection frequencies that can be expected using the new generation of survey instruments. The author's conclusion is that about 5000 dis/min of beta activity per particle, in low-density populations of discrete particles, is the minimum level of activity per particle that is applicable for confident compliance with surface contamination control guides. Lower control levels are possible with additional development of instruments or through high cost changes in radiation survey and contamination control methods. Additional analyses are required for assessment of the hazards caused by the widely dispersed, discrete particle contaminants.
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