Development and testing of methods for the non-invasive analysis of the inventory status for transport and storage containers during extended interim storage
Sub-Project: Radiation based imaging
Motivation:
Until the commissioning of a final waste repository for highly-radioactive waste in Germany, intermediate storage of spent fuel in dry storage casks is required. Thereby, prolonged intermediate storage times of more than 50 years have to be taken into consideration. For such long durations it is not yet possible to fully exclude the potential loss of integrity of fuel elements due to structural changes. The research project is dedicated to the development and testing of methods for non-invasive long-term monitoring of the container inventory based on the detection of cosmic muons and measurement of the gamma and neutron radiation field.
Objectives:
Based on the results of the DCS-Monitor project (2016 - 2019), the aim of this project is to investigate the approaches of radiation field-based diagnostics with gamma radiation, neutrons and muons in more depth and to qualify them in the direction of an applicable monitoring procedure especially for CASTOR containers. For the first time, this includes field studies on real casks and in the interim storage facility.
Methods and results:
A multi-channel prototypical hybrid detector for gamma photons and neutrons as well as a partially automated traversing unit for measurement operation in the interim storage facility will be set up. Based on Monte Carlo simulations and test measurements, the total measurement times, cross-sensitivities due to neighboring casks and measurement uncertainties for different field signatures with differently loaded casks will be determined. For the detection of muons, a modular and large-scale measurement system will be developed, taking into account the available muon flux and the sensitivity to gamma and neutron radiation. Based on simulations, a suitable detector arrangement and an associated imaging method (transmission, consideration of the scattering angles) will be developed by solving an inverse problem. A strategy for permanent or temporary cask monitoring will be derived for both measurement systems.