全世界越来越意识到与其下落大部分不明的商用辐射源有关的问题。由于这样或那样的原因,它们已不再受监管控制。随着辐射源被穿越国界运输,其影响超出了当初使用这些源的国家。这些不受管制的辐射源通常称之为“无管源”。这个术语一般用以包括如下一些源:从未置于监管控制之下的源;曾置于监管控制之下但后 The world is increasingly aware of the problems associated with most of the commercial sources of its whereabouts. For one reason or another, they are no longer under regulatory control. As radiation sources are transported across national boundaries, the impact goes beyond the countries that used the sources. These unregulated sources are often referred to as “sourceless.” This term is generally used to include sources such as those that have never been placed under regulatory control, those that were placed under regulatory control but then