Shell source method in radwaste assay

There are certain limitations concerning the usage of standard source method for efficiency calibration of gamma-ray spectrometers measuring in extended geometry. These limitations arise from the great diversity of forms and dimensions of the objects which are to be measured during decommissioning and radioactive waste management activities. The Institute for Nuclear Research (ICN) operates a radioactive waste management facility both for its own purposes and for providing external services, facility which is able to perform conditioning of liquid and solid wastes for interim storage. During the conditioning operations there are certain stages when the radioactive measurement of the storage drums is demanded. We developed a gamma ray spectrometry equipment using a portable MCA Canbera INSPECTOR, a HPGe detector and an ICN manufactured collimator and now we are using the shell source method to calibrate the gamma ray spectrometer for such measurements. (authors)