Leak detection of radioactive media esp. reactor cooling water - uses change in ratio of two nuclides of different half lives in surrounding atmosphere

摘要

A nuclide-specific activity measurement is carried out in the atmosphere adjacent to the ducting, at least two nuclides of differing half-life are distinguished and the relative proportions of these two nuclides are established; from the increase in the proportion of the short-life nuclide compared with the longer-life nuclide, an indication of a leak in the duct is obtd. Pref., the half-lives of the two nuclides differ by a factor of at least 10. Pref. nuclides are long-life nuclides: xenon 133. Short-life nuclide: Krypton 87 or xenon 138. Used for detecting leaks in the neighbourhood of ducts and other plant items esp. of water-cooled reactors. The method obviates the need for collecting drips of water themselves and carrying out measurements of them. Compared with this previous procedure, the new method is more accurate and involves less exposure of personnel to radioactivity.