Methods for reducing exposure to personnel leak-testing sealed radium sources

In a previous report, we proposed a group test procedure that would minimize exposure to personnel leak-testing sealed radium sources by reducing the required number of tests. The procedure was based on two assumptions: (a) there will be at most a single leaking source in any given test group, and (b) the resulting exposure is directly proportional to the number of leak tests performed. Whereas the validity of the first assumption finds its basis in leak test data available in the literature, the requirement of the second assumption may not be readily satisfied. In the present work, this requirement is lifted and consideration is given to the more realistic situation where the exposure is directly proportional to the activity of the group being tested. This leads to a group leak-testing procedure which in many instances results in a considerable reduction in exposure. Consideration is also given to storage arrangements and it is shown that, given an inventory of sealed radium sources, minimum exposure during leak-testing results when the distribution of sources among drawers is as alike as possible with respect to the number, arrangement, and activity of the sources per drawer-assuming use of our recommended leak-testing procedure (RGS)