Session: OAC-04-01 Storage and Transportation of Radioactive Materials-1

Paper Number: 123797

123797 - Consequences of an Imperfectly Mounted Reinforcement Cage in a Generical Cylindrical Concrete Container During Mechanical Specimen Tests 

By highest court decision in 2007 the issued license for the Konrad repository (a former iron ore mine) for low and intermediate level radioactive waste was finally confirmed. Since then, the site is improved, prepared and equipped for the currently planned start of waste package emplacement by 2029. The Bundesanstalt fuer Materialforschung und -pruefung (BAM, Federal Institute for Materials Research and Testing) is regularly contracted by the Bundesgesellschaft für Endlagerung (BGE, Federal Company for Radioactive Waste Disposal) as the responsible authority for waste product control, waste container design testing, and waste package acceptance. In this context BAM is mainly responsible for design testing of various container types including the evaluation quality assurance measures for container manufacturing.

In the written Konrad disposal requirements all acceptance criteria for potential final disposal containers are defined. In addition to general requirements concerning container design, materials, dimensions and others, specific mechanical load scenarios the casks have to withstand are derived from an analysis of the on-site handling and emplacement procedures. Drop tests from different heights under consideration of the most damaging drop orientation and a stacking test are two examples for safety demonstrations that have to be performed during the container design testing procedure to qualify the respective container type.

The containers, whether cubic or cylindrical containers, can be made from different materials like ductile cast iron, reinforced concrete or as welded construction from steel plates and profiles. In case of concrete containers the reinforcement has the function to absorb tensile forces the concrete is not able to withstand by its own. Because of manufacturing imperfections of cylindrical concrete waste containers manufactured already decades ago, the reinforcement cages are not always exactly, asymmetrically positioned when they were poured. This inspired BAM to perform various ABAQUS^Ò finite-element (FE) simulations by using the example of a simplified cylindrical container design with generic dimensions and pure elastic material properties. As outcome the stress conditions in the container during the drop test impact under different drop positions and during the stacking test were investigated and are explained and illustrated in this contribution. Different reinforcement cage positions were calculated and compared. On the basis of the calculated tensile and compressive stress distributions suggestions are derived on how a cylindrical concrete container with an imperfectly placed reinforcement cage has to be oriented for a drop or stacking test to ensure the most damaging test scenario.

Presenting Author: Mike Weber BAM

Presenting Author Biography: Mike Weber studied Mechanical Engineering at Dresden University of Technology from 1988 to 1993.
Between 1993 and 2005 he worked as a structural and designing engineer in the field of steel and concrete construction.
Since 2006 he has been working at Bundesanstalt fuer Materialforschung und -pruefung (BAM), Division “Safety of Storage Containers”. He has a long experience in the mechanical assessment of transport and storage containers and in developing, creating and evaluating of comprehensive static and dynamic finite element models.
Since 2016: active participation in organization of the annual ASME PVP Conference (OAC-4)

Authors:

Mike Weber BAM
Holger Völzke BAM
Gregor Nieslony BAM