Determination and use of scaling factors for waste characterization in nuclear power plants
Disposal of radioactive waste requires knowledge of its radioactivity content in terms of the concentrations of specific radionuclides. This information is used by the repository operator and/or regulator to track radionuclide inventories and concentrations, which are generally limited by the repository safety assessment and resulting operating licence. It is normally the responsibility of waste generators to evaluate and declare the activity content of their waste. The repository safety assessment typically identifies a relatively small set of long lived radionuclides that are more or less limited by the specific design of the disposal site. Many of the important long lived radionuclides contained in the radioactive waste are difficult to measure (DTM) from outside the waste packages using non-intrusive techniques because they are low energy, non-penetrating beta or alpha emitting nuclides (i.e. non-gamma emitters). Identification of these DTM nuclides requires methods that, in general, involve analysis of waste samples using complex chemical analysis to separate the various radionuclides for measurement. This method is not practical to employ for large numbers of waste packages.