Development of a mobile, automated, optical inspection system for radioactive barrels

Abstract

Abstract. Due to the delayed construction and commissioning of a German repository for intermediate- and low-level radioactive waste, waste inventories from several decades are now located at the interim storage sites, the safe custody of which must also be ensured for an indefinite period of interim storage. The usual practice in the interim storage facilities is recurrent inspections, which are carried out almost exclusively manually and without electronic comparative recordings as well as without mechanical documentation and archiving. Remote or automated inspection does not take place. The inspections are carried out visually and are therefore very subjective and thus subject to errors. Manual performance is labor intensive and requires the use of personnel exposed to radiation. Neither are uniform inspection criteria of the visual inspections applied, nor are the inspections performed uniformly between sites. Based on these facts, the Institute for Technology and Management in Construction, Department of Deconstruction and Decommissioning of Conventional and Nuclear Buildings, together with the Institute for Photogrammetry and Remote Sensing, is developing an automated drum inspection system as part of the funding measure FORKA – Research for the Deconstruction of Nuclear Facilities. EMOS is a mobile inspection unit that remotely and automatically records the entire surface of the drum, including lid and bottom, optically; evaluates it analytically; and both stores it electronically and outputs the results in the form of an inspection report. In this way, recurring inspections of the drum stock can be completed under the same inspection conditions each time. A decisive advantage is the possibility of carrying out the inspection remotely in order to reduce the radiation dose to the employees on site. The optical evaluation, display and output of the results will ensure a more precise inspection and analysis of the drum surfaces through software to be specially developed than is possible through manual and visual inspections as currently performed in the interim storage facilities. The continuous monitoring of the stored drums will be facilitated and also the tracing of possible damage development through the comparison of archived measurement results is a novel and powerful tool that helps to increase and ensure the safety aspects of interim storage in the long term. Changes in drum geometry as well as in the surface condition (e.g. corrosion formation, etc.) can be identified at an early stage with the help of the inspection unit, and measures can be taken at an early stage to counteract the loss of integrity of the storage containers.