Random checks on waste packages prior to disposal

Random checks are possible by non-destructive assay techniques (NDA) and by destructive sampling. NDA is based on penetrating radiation. The gamma scanner Gernod is discussed in detail as the most promising NDA technique. The specific activity of the item is primarily dtermined. A large part of the volume of a waste barrel is easily accessible. The barrel is therefore a preferred item for testing. The most useful method of destructive sampling is drilling. Many matrix parameters can be checked by inspecting the core or the borehole. Chemical analysis starts from the drilling dust. The preparation of samples for alpha and beta spectroscopy is illustrated. Drums with a surface dose rate << 2 mSv/h are checked by the glove-box technique, whereas drums with a higher surface dose rate or concrete-shielded waste packages and cast iron containers are examined by remote handling. The installations are presented and explained. The optimum combination of checks includes nuclide correlations known from the documentation and relies mainly on NDA. (orig./DG)