Geophysics methods and their applicability in nuclear safeguards in geologic repositories during construction and operation

The use of geophysics methods in international safeguards procedures in spe nt nuclear fuel repositories has been under discussion for several years. M easurements employing active and passive electromagnetic as well as seismic techniques are considered particularly suitable for detecting undeclared a ctivities in a repository. The article contains an evaluation of the possib ilities and limits associated with these techniques. Estimates conducted so far have been based mainly on experience with geophy sics in exploring raw materials deposits, solving problems of geo-engineeri ng, and in mine safety. This shows that there are hardly any studies specif ically of the use of these techniques in nuclear safeguards. No general ass essment exists of any of the methods proposed, as site-specific conditions and different emplacement and storage concepts have a major impact on the a pplicability of these techniques. In this respect, work focusing on specifi c aspects will have to be carried out in the future, such as the studies pl anned in Germany of the use of passive seismics in saline host rock. The results of a modeling study of using active seismics are presented. The se studies showed that it is possible in principle to employ seismic techni ques below ground. However, the expense in terms of technology and manpower is very great, Consequently, the envisaged use of this technique for inspe ction purposes seems to be impossible.