Filtern
Erscheinungsjahr
Dokumenttyp
- Beitrag zu einem Tagungsband (52)
- Vortrag (50)
- Zeitschriftenartikel (9)
- Posterpräsentation (9)
- Beitrag zu einem Sammelband (8)
- Buchkapitel (1)
- Dissertation (1)
Referierte Publikation
- nein (130) (entfernen)
Schlagworte
- Seal (21)
- Ageing (19)
- Compression set (11)
- Elastomer (11)
- Rubber (10)
- Metal seal (9)
- Degradation (8)
- Dichtung (8)
- Low temperature (8)
- Aging (7)
- Rubber seal (7)
- Creep (6)
- Irradiation (6)
- O-Ring (6)
- Alterung (5)
- Elastomere (5)
- Leakage (5)
- O-ring (5)
- Tieftemperaturverhalten (5)
- Compression (4)
- Dichtungen (4)
- Druckverformungsrest (4)
- Glass-rubber transition (4)
- Leakage rate (4)
- Long-term behavior (4)
- Glasübergang (3)
- Leckagerate (3)
- Partial release (3)
- Seal performance (3)
- Cask (2)
- Disposal (2)
- Dynamic mechanical analysis (2)
- Gamma irradiation (2)
- Hydrogen (2)
- Konrad repository (2)
- Lifetime (2)
- Long-term behaviour (2)
- Metalldichtung (2)
- Metallic seal (2)
- Neutron shielding (2)
- Radioactive Waste (2)
- Radioactive waste containers (2)
- Recovery (2)
- Transport- und Lagerbehälter für radioaktive Stoffe (2)
- (U)HMW-PE (1)
- (U)HMWPE (1)
- Back end (1)
- Brittle failure (1)
- Cask for storage and transport of radioactive materials (1)
- Co-60 irradiation (1)
- Coefficient of Friction (1)
- Component tests (1)
- Crack propagation (1)
- Crack resistance (1)
- Cure monitoring (1)
- DMA (1)
- DSC (1)
- Dichtheit (1)
- Dichtsysteme (1)
- Dielectric relaxation (1)
- Dual purpose cask (1)
- EPDM (1)
- EVA (1)
- Editorial (1)
- Elastomer Dichtung (1)
- Elastomer seal (1)
- Elastomer seals (1)
- Elastomerdichtung (1)
- Elastomers (1)
- Experiment (1)
- Extended interim storage (1)
- Extended storage (1)
- Extrapolation (1)
- Federunterstützte Metalldichtungen (1)
- Ferroelectric polymer (1)
- Fracture mechanics (1)
- Fracture toughness (1)
- Fuel cladding (1)
- Getting started (1)
- Glas-Gummi-Übergang (1)
- Glass transition (1)
- HMW-PE (1)
- Helium-Dichtheitsprüfung (1)
- Infrared and far-infrared spectroscopy (1)
- Injection moulding (1)
- Interim storage (1)
- Klebfolie (1)
- Langzeiteignung (1)
- Langzeitversuche (1)
- Leakage Rate (1)
- Life time prediction (1)
- Lifetime criterion (1)
- Lifetime evaluation (1)
- Long-term safety (1)
- Long-term storage (1)
- Low temperature behaviour (1)
- Machine element (1)
- Material model (1)
- Metal seals (1)
- Modelling (1)
- Neutron radiation shielding material (1)
- Neutronen Abschirmmaterial (1)
- Nuclear fuel cycle (1)
- Numerical Simulation (1)
- Numerical analysis (1)
- O Ring (1)
- O ring (1)
- On-line monitoring (1)
- P(VDF-HFP) (1)
- PV modules (1)
- Partial crystalline (1)
- Photovoltaik (1)
- Plastics (1)
- Poly(vinylidene(fluoride - hexafluoropropylene) (1)
- Polyethylene (1)
- Polymer Testing (1)
- Ring compression test (1)
- Rubber seals (1)
- SHPB (1)
- Seal Behavior (1)
- Seal behaviour (1)
- Seal properties (1)
- Sealing material (1)
- Shape memory polymer (1)
- Shielding material (1)
- Simulation (1)
- Sound velocity (1)
- Spent fuel performance (1)
- Storage (1)
- Storage cask (1)
- Stress relaxation (1)
- Structure-property relationship (1)
- Struktur-Eigenschaftsbeziehung (1)
- Testing (1)
- Tiefe Temperaturen (1)
- Transportation (1)
- UHMW-PE (1)
- Ultrasonic (1)
- Ultrasound (1)
- Uniaxial stretching (1)
- Versagenstemperatur (1)
- Vulcanisation (1)
- Vulcanization (1)
- WAXD (1)
- Zwischenlagerung (1)
- analysis techniques (1)
- encapsulation (1)
- glass-rubber transition (1)
- leakage rate (1)
- low temperature behavior (1)
- polymer encapsulant (1)
- seal, rubber (1)
- solar cells (1)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (50)
Ultra high molecular weight polyethylene (UHMW-PE) - due to its high hydrogen content - is used as neutron shielding material in casks for storage and transport of radioactive materials. Besides this, UHMW-PE - as a high-performance polymer - has been used for several years in medical technology due to its excellent slip and wear properties. Due to the special properties of UHMW-PE which result basically from its extreme chain lengths and its high degree of crystallinity, it is predestinated for the aforementioned applications.
In both cases, irradiation and its impact on the molecular structure of polyethylene play an important role. In the first case, irradiation exists as a by-product of inserting the radioactive material in the cask. Hence PE has to withstand any type of degradation affecting safety relevant aspects to be applicable for long term radiation shielding purposes for instance over a period of 40 years. In the second case irradiation is applied deliberately for purposes such as sterilization and crosslinking, leading to partial improvement of the mechanical properties (e.g. fracture toughness, crack propagation resistance, wear resistance) and better Chemical stability.
Specifically concerning their use in the field of medical technology, different types of UHMW-PE have been objects of numerous publications. It is generally accepted that two parallel and competitive processes, based on chain scission and reactions of Ccentered radicals and molecular fragments, occur in PE as a consequence of radiation: radical recombination accounts for crosslinking, together with some disproportionation, formation of low molecular weight fragments, and recrystallization. Furthermore, formation of oxygenated structures in the presence of traces of oxygen is an antagonist of the C-centered radicals. Radiation induced scission preferentially takes place in the amorphous phase and noncrystalline surface of the crystals. It is followed by folding of molecular fragments, crystallinity growth and increased perfection in the crystal lamellae [4, 5]. Chain scission results in shorter polymer molecules, fewer entanglements, and consequently, increased molecular mobility.
The scope of our investigation comprises an estimation of the radiation and thermal impact on the molecular and supra molecular structure of the two types of PE used for neutron shielding cask components. A further point which is worth to explore is to what extent these changes are detectable by thermo-analytical (TA) methods, such as Differential Scanning Calorimetry (DSC), Thermo Mechanical Analysis (TMA), Dynamic Mechanical Analysis (DMA) and Thermogravimetry (TG). Additionally FT-IR and solubility measurements have been performed.
In our studies we focused on the UHMW-PE material GUR 4120 which was y irradiated at RT and compared to the untreated material.
Einfluss der Alterung auf dichtungsrelevante Eigenschaften von FKM-, VMQ- und EPDM-Elastomeren
(2017)
Da Elastomere in vielfältigen Dichtungsanwendungen eingesetzt werden und dabei teilweise großen Einfluss auf die Funktionsfähigkeit und Sicherheit haben, ist der Einfluss der Alterung auf dichtungsrelevante Eigenschaften relevant. Eine strukturierte Untersuchung des Einflusses von verschiedenen Mischungsrezepturen auf die Bauteileigenschaften, das Alterungsverhalten und die Funktion wird vorgestellt.
Elastomer seals are widely used as barrier seals in containers for low and intermediate level radioactive waste. In addition, they are also used in waste fuel storage and transportation casks as auxiliary seals. Depending on the area of use, the rubber materials have to demonstrate proper sealing performance with respect to mechanical, thermal and environmental conditions as well as irradiation during the entire operation period. A fundamental understanding of the structure property relationship and their changes during aging can help to evaluate the long-term sealing performance.
In the present study, specific materials are investigated to study the structure-property and seal performance-correlation. Fluoro-elastomer (FKM), silicone rubber (VMQ) and ethylene propylene diene rubber (EPDM) were chosen as base rubbers. Comparable mechanical properties for these seals, especially in terms of a comparable compression behavior were achieved by careful control of base rubber formulation, i.e., by opting for the right filler and its concentration, amount of crosslinking chemicals, and with the assistance of process oils. Moreover, with the same rubber, similar mechanical properties were achieved by varying the filler concentration and crosslinking degree, which shall enable to correlate the particular influence on the structure property dependency of the seals in detail. The materials are investigated under pristine and aged conditions to evaluate the influence of aging, e.g. on the stress relaxation or recovery behavior. These values appear to be suitable parameters to judge the expected sealing performance.
Due to the electrically conducting nature of some fillers used to reinforce rubbers (such as carbon blacks, carbon nanotubes (CNTs), Graphene, etc.) it is possible to obtain current information about mechanical and visco-elastic properties by monitoring the electrical conductivity or resistivity. A simple relation that relates electrical resistance with mechanical stress was derived and the stress values were theoretically predicted from the electrical resistance values, which showed good correlation with experimental results.
Thermoanalytische Charakterisierung von Ethylen-Vinylacetat-Copolymer (EVA) für Photovoltaikmodule
(2011)
Das Ziel der Untersuchungen war mit Hilfe von DSC und DMA EVA-Folien im Anlieferungszustand hinsichtlich der Lage der Glasübergangstemperatur, des Schmelzverhaltens und der Temperaturabhängigkeit der Vernetzungsreaktion zu charakterisieren. Auf dieser Basis sollte die Lieferstabilität im Sinne einer Wareneingangskontrolle auf eine messtechnische Basis gestellt werden. In einem 2. Schritt sollte die vernetzte Folie dahingehend charakterisiert werden, ob infolge der Vernetzung eine Änderung der
It is important to evaluate the effect of thermal ageing on the sealing performance of metal gaskets under high temperature for long-term usage. Therefore, in order to gain representative data for this kind of metal-sealed lid System, BAM is currently performing laboratory tests of different gasket types with aluminum and silver jackets at three different temperatures under static conditions up to four years so far, using test flanges for gaskets with full scale cross section diameter but much smaller outer diameter. On the other hand, in order to investigate the applicability of the numerical methodology to evaluate the long-term behavior of the metal gaskets, such as a correlation between seal pressure force and holding time, CRIEPI is developing a modeling method including material tests (tensile and creep tests) at high temperature. In this paper, the applicability of the finite element method (ABAQUS) to predict the recovery displacement and residual seal pressure force of the gasket complex was verified by comparing the calculated values with BAM’s laboratory test results under the joint research agreement between BAM and CRIEPI.
Langzeituntersuchungen an Metalldichtungen mit innen liegendem Federkern und doppelter Ummantelung
(2013)
In Deutschland werden in Transport- und Lagerbehältern (TLB) wärmeentwickelnde radioaktive Abfälle gegenwärtig über einen Zeitraum von bis zu 40 Jahren zwischengelagert. Aufgrund der Situation der noch nicht abgeschlossenen Endlagersuche werden hier möglicherweise Verlängerungen in Betracht zu ziehen sein. Im Deckeldichtsystem der TLB werden in der Regel Metalldichtungen vom Typ Helicoflex® eines französischen Herstellers verwendet, die aus einem innen liegenden Spiralfederkern und zwei Ummantelungen bestehen. Die Ermittlung der Fliess- und Relaxationseigenschaften der Dichtungskomponenten über den vorgesehenen langen Betriebseitraum sind vor dem Hintergrund des Erhalte eines geforderten hohen Dichtniveaus ein wichtiger Untersuchungsgegenstand.
A Memorandum of Understanding (MOU) between Argonne National Laboratory (Argonne) and the German Bundesanstalt für Materialforschung und -prüfung (BAM) was signed in October 2014. Its objectives are to promote cooperation among scientists and specialists at Argonne and BAM and establish a framework for collaboration in advanced technologies associated with the back end of the nuclear fuel cycle. Collaborative activities involving Argonne and BAM may be implemented through the promotion of joint research activities and scientific workshops and conferences; exchange of technical information; and visits by scientists, specialists, and graduate, postgraduate, and Ph.D. students. The MOU was renewed in January 2020 for another five years. Highlights of the progress and achievements are provided in identified topical areas for collaboration on ageing management guidance, storage, transportation and disposal R&D, joint conference activities, and conclude with the benefits of the MOU in fostering Argonne and BAM collaboration.
Elastomers are widely used as the main sealing materials in Containers for low- and intermediate-level radioactive waste and as an additional component fo metal seals in spent-fuel and high-level waste containers. According to appropriate guidelines and regulations, safe enclosure of the radioactive container contents has to be guaranteed for lengthy storage periods of at least 40 years. Therefore, the understanding of seal ageing behaviour is of high importance and has to be considered with regard to possible dynamic events taking place during transport after storage. An accelerated ageing approach for compressed seals is presented, as well as some first results.