Filtern
Erscheinungsjahr
Dokumenttyp
- Beitrag zu einem Tagungsband (25)
- Vortrag (7)
- Zeitschriftenartikel (4)
- Posterpräsentation (2)
Sprache
- Englisch (24)
- Deutsch (13)
- Mehrsprachig (1)
Schlagworte
- Drop test (8)
- Damping concrete (7)
- Dämpferbeton (4)
- Polyurethane foam (4)
- Dehnratenabhängigkeit (3)
- Impact limiter (3)
- Material model (3)
- Material models (3)
- Materialmodellierung (3)
- Strain rate sensitivity (3)
- Cask (2)
- Drop testing (2)
- Drop tests (2)
- Dynamic (2)
- Fem (2)
- Guided drop tests (2)
- IAEA (2)
- Material characterisation (2)
- Numerical simulation (2)
- Parameter identification (2)
- Penetration (2)
- Polyurethan Schaum (2)
- Spruce (2)
- Spruce wood (2)
- Stoßbelastung (2)
- Stoßdämpfende Werkstoffe (2)
- Strain rate (2)
- Temperaturabhängigkeit (2)
- Temperature dependency (2)
- Temperature sensitivity (2)
- Versuchsprogramm (2)
- Antragsverfahren (1)
- Assessment method (1)
- Bar length (1)
- Beton-Polymer Verbundwerkstoff (1)
- Characterisation material behaviour (1)
- Charakterisierung Materialverhalten (1)
- Component size (1)
- Compression tests (1)
- Concrete-polymer composite (1)
- Crush test (1)
- Crushing test (1)
- Design assessment of RAM packages (1)
- Druckversuche (1)
- Dual purpose cask (1)
- Ductile cast iron (1)
- Dynamic compression (1)
- Dynamic compression tests (1)
- Dynamic crushing characteristics (1)
- Dynamisch (1)
- Dynamische Druckversuche (1)
- Eindringversuche (1)
- Encapsulations for damaged spent nuclear fuel (1)
- Experimental testing (1)
- Fichtenholz (1)
- Finite element model (1)
- Finite elements (1)
- Fire test (1)
- Geführte Fallversuche (1)
- Hankinson's formula (1)
- Impact loading (1)
- Impact test (1)
- Internal gaps (1)
- Internal shock absorber (1)
- J-integral (1)
- Lateral constraint (1)
- Limiter (1)
- Material model wood (1)
- Materialmodell (1)
- Mechanik (1)
- Multiaxial stress state (1)
- New package design (1)
- Numerical modelling (1)
- PU-Schaum (1)
- Package (1)
- Package design (1)
- Package testing (1)
- Plasticity (1)
- Plasticity model (1)
- Puncture test (1)
- Rate dependency (1)
- SNF (1)
- Simulation (1)
- Temperatursensitivität (1)
- Thermik (1)
- Transport (1)
- Transport package (1)
- Transportbehälter (1)
- Typ-B Versandstück (1)
- Zulassungen (1)
- radioaktives Material (1)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (7)
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.
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.
Polyurethane foam used as impact limiter material undergoes high plastic deformations, whereat the resulting stress-strain relations strongly depend on loading speed and temperature. This paper discusses the efforts necessary to develop a reliable numerical foam simulation model focussing on generation and implementation of temperature- dependent yield curves
In drop test scenarios related to assessing and licensing the storage procedure of spent fuel and high active waste, the casks under examination are generally not equipped with impact limiters. Hence, the extent of mechanical stresses in case of an assumed handling accident is largely affected by the ground properties of the reception hall floor in the specific storage facility.
Unlike conventional brittle foundation materials, damping concrete performs quite well in such applications as it features high stiffness as well as high energy absorption due to the filler pore volume. However, its damping ability is not sufficiently exploited in current finite element (FE) calculations due to a lack of advanced material models for simulating its impact response. An implementation of qualified concepts that account for plastic, strain rate dependent behavior requires additional information that has to be provided by systematic test series.
BAM recently started a research project to generate such data, subsequently to develop and to improve numerical methods for the analysis of impact limiters and damping foundation material and thus to optimize safety assessment tools for the design of transport and storage casks. A major part of this research concerns dynamic compression tests of variably shaped specimens conducted at a servo hydraulic 1MN impact testing machine as well as at a BAM facility for guided drop tests. This presentation focuses 100mm damping concrete cubes deformed vertically at constant rates under different constraint conditions. For example, a special fitting jig was constructed to subject the specimens to multi-axial loading. Thereby a deformation of 60% could be applied.
Simulation was conducted by FE code ABAQUS based on material models Concrete damaged plasticity and Crushable foam which both allow defining rate sensitive nonlinear stress-strain relations in compression beyond the classic metal plasticity approach.
Finite element analysis (FEA) has been carried out for investigation of damping concrete under different impact loading conditions with a built-in material model and damage criteria available in FEA code ABAQUS.
At first, all parameters for the selected material model had been derived from compression Tests of cubic specimens. After that, a validation was carried out with different static and dynamic penetration tests. Finally, a 5 meter real drop test with a 23 Mg cylindrical cask could successfully be simulated.
Experimental and numerical studies of shock absorbing materials for containers for radioactive waste
(2012)
Im Zuge des Forschungsvorhabens ENREA (Entwicklung rechnerischer Analysemethoden für stoßdämpfende Strukturen beim Anprall oder Absturz von Abfallgebinden) führt die BAM systematische Untersuchungen an stoßdämpfenden Werkstoffen, unter anderem an Fichtenholz, durch. Zweck der mit diesen Untersuchungen erzeugten Datenbasis ist die Erstellung und Parametrierung eines Finite-Elemente- (FE-) Materialmodells, das die Modellierung holzgefüllter stoßdämpfender Bauteile von Transportbehältern für radioaktive Stoffe in der FE-Simulation ermöglichen soll.
Anhand von Ergebnissen aus der ersten Versuchsphase werden der Einfluss der Dehnrate und der Faserorientierung auf das Kraft-Verformungs-Verhalten von Fichtenholz diskutiert. Anschließend wird die rechnerische Modellierung von Fichtenholz diskutiert und die Anforderungen an ein Materialmodell werden erläutert.