Methods for the non-invasive analysis of the inventory status for containers during extended interim storage (DCS-Monitor II)

In the completed project DCS-MONITOR, feasibility studies for non-invasive monitoring of the container contents were carried out by the applicants using numerical and laboratory experimental tools. Radiation-based measurement techniques, thermography, acoustic spectroscopy and technical vibration analysis were investigated for their suitability. The previous analyses showed that the photon and neutron field around the vessel, muon imaging and passive acoustic spectroscopy are in principle suitable for monitoring the vessel inventory, but also differ in their informative value. For thermography, a lack of informative value was found for physical reasons. For active vibration diagnostics, technical hurdles and informative value were assessed negatively. With regard to passive acoustic spectroscopy, experts also dispute whether embrittled cladding tubes burst at all, with a corresponding sound emission in the container. On the basis of these results, the approaches of radiation field-based diagnostics with gamma radiation, neutrons and muons are investigated in more detail within the project DCS-MONITOR II in order to qualify them as an applicable monitoring procedure especially for CASTOR casks. For the first time, this includes studies on large scale geometries and containers.