Drop and fire testing of spent fuel and HLW transport casks at 'BAM test site technical safety'
(2011)
BAM, as a competent German government institute for the mechanical and thermal testing of radioactive material transport and storage containers, operates unique drop and fire test facilities for experimental investigations on the open air BAM Test Site Technical Safety. To be able to perform even drop tests with full scale spent fuel or HAW casks (i.e. the German CASTOR cask designs), BAM constructed in 2004 a large drop test facility capable to handle 200 ton test objects, and to drop them onto a steel plate covered unyielding target with a mass of nearly 2600 ton. Drop test campaigns of the 181 ton GNS CONSTOR V/TC, the 129 ton MHI MSF-69BG and a 1:2 scale model of the GNS CASTOR HAW28M (CASTOR HAW/TB2) have been performed since then. The experimental BAM drop testing activities can be supported also by drop testing of smaller packages (up to 2 ton) in an in-house test facility and by dynamic, guided impact testing of package components and material specimen inside a new drop test machine. In May 2008, a new modern fire test facility was put into operation. The facility provides two test stands fired with liquid propane. Testing in every case has to be completed by computational investigations, where BAM operates appropriate finite element modelling on appropriate computer codes, e.g. ABAQUS, LS-DYNA, ANSYS and other analytical tools.
This paper presents a comparison between full scale prototype and reduced scale model drop test data in regard to similarity mechanics. Together with a current BAM research project, the paper contributes to the further development of mechanical evaluation methods for safety assessment of RAM transport and storage packages including the transferability of package impact response from reduced scale models to full scale packages.
In context with Japanese disposal and transport container safety assessment the German Federal Institute for Materials Research and Testing (Bundesanstalt für Materialforschung und -prüfung) per-formed extensive drop test series with prototypes of RAM packages in recent years.
The paper presents two cooperative projects focused on project management, testing performance and experimental results.
In the first project, a full-scale prototype of a package for transport and storage of spent fuel elements with a total mass of 127,000 kg and its reduced-scale model which was similar to the prototype in both geometry and design were drop tested in 9 m and 1 m puncture tests at various drop orientations under regulatory conditions. In context with a corresponding research project the test data was used in combination with numerical methods to investigate the phenomenon of internal cask- content collisions during drop tests. Here, technological gaps between basket or radioactive content and cask body or primary lid can be a reason for significant high dynamic loadings of cask components and its internals due to additional impact interactions in the cask cavity caused by inner relative movement between content and cask. Further investigations were carried out in the field of similarity mechanics comparing experimental drop test data of the full-scale prototype and reduced-scale model in regard to the transferability of package impact response from reduced-scale models to full-scale packages.
In the second project, drop tests with a waste container for intermediate depth disposal were per-formed being contracted by Kobe Steel, Ltd. and a consortium of Japanese electric power plant com-panies. The drop test program comprised three single 8-m drop tests in a specimen’s corner edge orientation. For drop tests according to legal regulations for interim storage or final disposal it is often necessary to use a target which represents the real ground of the storage facility. In such cases the container hits directly onto a well-defined concrete slab on top of the IAEA target. Here, the directly impact target for the drop tests were concrete slabs manufactured in Japan and connected by mortar to the impact pad of the unyielding IAEA target.
Drop testing of a container for the storage. transport and disposal of intermediate level waste
(2017)
Impact tests were performed, as part of a corresponding container’s substantiation, during design development of a shielded container. The container will be used for storage, transport, and disposal of intermediate level waste in the UK.
The mechanical test program comprised a 9m free drop test onto an unyielding target in a container long lid edge down orientation at ambient conditions. Further, a 0,5m free drop test onto a punch target was performed. Here, the container was orientated with the lid downwards in a way that the punch, a mild steel bar, impacts a filter lid.
The test specimen was instrumented with strain gauges and accelerometers for the drop tests. Transient strains at selected points of the inner and outer container walls, at the shielding lid, as well as at the lid bolts were measured during the container’s impact. Furthermore, decelerations of the container body, container lid, and the skip were measured. The complex geometrical changes of the container due to impact were determined by optical 3d- deformation measures using the projected fringes method in combination with multi-image photogrammetry.
This paper summarizes the performance of the drop tests and various drop test results in context with the design development as well as aspects regarding the associated Finite Element (FE) analyses and post-test evaluation.