Uncertainty estimation in non-destructive characterization of radioactive waste packages: some general remarks

Segmented gamma scanning is a widely used method for identification and quantification of gamma-emitting nuclides in a waste package containing radioactive materials. The quotation of uncertainties nevertheless is challenging, as one has to differentiate between uncertainties based on statistical effects and those on lack-of-knowledge on the real content in the waste package (i.e. bias). Usually only the first is reported, while the effect of the latter might be the most dominant part. We present a simple approach considering the lack-of-knowledge in data evaluation and compare these results with the results of considering statistical uncertainties for a real waste package inspected at the ZTWB Radiochemie Munchen (RCM) of the Technische Universitat Munchen.