Limitations to the accurate assessment of waste actinide content by neutron interrogation

The characteristics of neutron techniques for assessing the actinide content of low and intermediate level wastes are described. The limitations of these methods as applied to the assessment of U, and Pu, and mixed wastes are reviewed. It is pointed out that the choice of instrument or combination should be made appropriate to the assay requirement. When the waste streams are well known and of fixed isotopic composition, simpler and cheaper arrangements are appropriate, but for mixed wastes of variable composition a larger number of sophisticated techniques must be used to obtain adequate assay accuracy