TY - CONF A1 - Müller, Lars A1 - Scheidemann, Robert A1 - Schönfelder, Thorsten A1 - Komann, Steffen A1 - Wille, Frank T1 - Drop tests assessment of internal shock absorbers for packages loaded with encapsulations for damaged spent nuclear fuel N2 - Damaged spent nuclear fuel (DSNF) can be loaded in German dual-purpose casks (DPC) for transport and interim storage. Encapsulations are needed to guarantee a safe handling and a tight closure, separated from the package enclosure. These encapsulations shall be durable and leak-tight for a long storage period, because they are usually not accessible within periodical inspections of the DPC. Due to the general design of DPCs for standard fuel assemblies, specific requirements have to be considered for the design of encapsulations for DSNF to ensure the loading in existing package designs. Especially the primary lid system of a DPC is designed for maximum loads due to the internal impact of the content during drop test conditions. The main difference of encapsulations for damaged spent nuclear fuel is that they have usually a much higher stiffness than standard fuel assemblies. Therefore the design of an internal shock absorber, e.g. at the head of an encapsulation is required to reduce mechanical loads to the primary lid system during impacts. BAM as part of the German competent authority system is responsible for the safety assessment of the mechanical and thermal package design, the release of radioactive material and the quality assurance of package manufacturing and operation. Concerning the mechanical design of the encapsulation BAM was involved in the comprehensive assessment procedure during the package design approval process. An internal shock absorber was developed by the package designer with numerical analyses and experimental drop tests. Experimental drop tests are needed to cover limiting parameters regarding, e.g. temperature and wall thickness of the shock absorbing element to enable a detailed specification of the whole load-deformation behavior of the encapsulation shock absorber. The paper gives an overview of the assessment work by BAM and points out the main findings which are relevant for an acceptable design of internal shock absorbers. The physical drop tests were planned on the basis of pre-investigations of the applicant concerning shape, dimension and material properties. In advance of the final drop tests the possible internal impact behavior had to be analyzed and the setup of the test facility had to be validated. The planning, performance and evaluation of the final drop tests were witnessed and assessed by BAM. In conclusion it could be approved that the German encapsulation system for damaged spent nuclear fuel with shock absorbing components can be handled similar to standard fuel assemblies in existing package designs. T2 - Pressure Vessels & Piping Conference 2020 CY - Online meeting DA - 03.08.2020 KW - Encapsulations for damaged spent nuclear fuel KW - Drop tests KW - Internal shock absorber KW - Design assessment of RAM packages PY - 2020 SP - 1 EP - 9 AN - OPUS4-51546 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wille, Frank A1 - Quercetti, Thomas A1 - Scheidemann, Robert T1 - Test Facilities for Radioactive Materials Transport and Storage Packagings at BAM N2 - BAM acts as authority and for service in safety assessment of packages for transport and storage of radioactive materials. We offer extensive test capabilities and application of analytical methods for design verification and simulation for all types of packages for the transport and storage of radioactive materials according with the international IAEA Regulations for the safe transport and for national storage acceptance criteria. BAM operates several test facilities for drop and stacking testing, leak testing and thermal testing. The large drop test tower allows dropping full-scale specimens up to 200,000 kg in any drop orientation as requested. The comprehensive test facilities combined with long-term experience, newest equipment and measurement devices according to the latest state-of-the-art technology ensures realisation of complex test campaigns for package safety evaluation. Beyond that, non-destructive and destructive material test devices and experts are available. Equipment and application of all kinds of typical measurement categories can be offered for testing campaigns. In recent years we performed testing of full-scale type B package models with complex handling and preparation procedures. The results were contributed for different package design approval procedures. Type A packages mainly designed for medical related transport purposes, were continuously tested according to the transport regulations over recent years as well. Moreover, we work on research topics with relevance to package safety. The mechanical behaviour of lid closure systems under transport and storage conditions and the thermal behaviour of impact limiters were recently of special importance for the assessment competencies of BAM and were investigated under use of our test facilities. The paper describes the test facilities and capabilities for package design safety evaluation at BAM and shows examples from our recent work. T2 - PATRAM 2022, 20th International Symposium on the Packaging and Transportation of Radioactive Materials CY - Juan-les-Pins, France DA - 11.06.2023 KW - IAEA KW - Fire test KW - Drop testing KW - Transport KW - Package PY - 2023 SP - 1 EP - 12 AN - OPUS4-57967 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Lars A1 - Scheidemann, Robert A1 - Neumeyer, Tino A1 - Neumann, Martin A1 - Komann, Steffen A1 - Wille, Frank T1 - Thightness Assessment of welded Lids for Encapsulations of damaged Spent Nuclear Fuel in the Design Approval Process of Dual-Purpose Casks (DPC) N2 - The disposal of spent nuclear fuel in Germany is ensured using dual-purpose casks (DPC) for transport and interim storage. The leak tightness of the DPC and resulting containment is one of the most important aspects. Additional encapsulations are required for damaged spent nuclear fuel (DSNF) to guarantee safe handling and a separate tight closure. Due to the general design of DPCs for standard fuel assemblies should special requirements be considered for the design of the encapsulations for DSNF to ensure the loading in existing package designs. The absence of a replaceable sealing in the tightness barrier is the main difference for the encapsulations for damaged spent nuclear fuel. Instead, they are welded shut with a lid. The leak tightness of the encapsulation shall be proven in the design approval process for all transport conditions. This is especially valid for accident conditions of transport, where high internal impact forces may occur. BAM as German competent authority is responsible for the safety assessment of mechanical and thermal design, retention of radioactive material and quality assurance aspects of manufacturing and operation. BAM carried out a comprehensive safety assessment concerning the mechanical package design. As there are no representative standards for verifying the leak tightness of a welded lid, two approaches were being pursued. Established German standards may be used for verifying the leak tightness of a weld - but limited to low stresses. Therefore, physical tests were required for higher impact loads. Representative drop tests and highly sensitive leakage tests were performed. The paper presents an overview of the containment assessment by BAM and points out the main findings for the design of welds regarding leak tightness. Both verification procedures are described, on one hand with German standards for lower loads and on the other hand with physical tests for higher impact loads. The leak tightness of the encapsulation weld could be approved based on leakage tests and a corresponding evaluation for all transport conditions. T2 - PATRAM 2025 CY - San Antonio, Texas, USA DA - 27.07.2025 KW - Transport packages KW - Tightness assessment KW - Welded lids KW - Encapsulations PY - 2025 VL - 2025 SP - 1 EP - 11 PB - Institute of Nuclear Materials Management (INMM) CY - Indianapolis AN - OPUS4-64023 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -