Filtern
Erscheinungsjahr
Dokumenttyp
- Beitrag zu einem Tagungsband (110)
- Vortrag (88)
- Zeitschriftenartikel (26)
- Forschungsbericht (7)
- Beitrag zu einem Sammelband (6)
- Posterpräsentation (3)
- Buchkapitel (2)
- Monografie (1)
- Sonstiges (1)
Sprache
- Englisch (135)
- Deutsch (108)
- Mehrsprachig (1)
Schlagworte
- Behälter (18)
- Endlager (16)
- Safety (13)
- Interim storage (11)
- Metal seal (11)
- Storage (11)
- Bauartprüfung (10)
- Simulation (9)
- Spent fuel (9)
- Disposal (8)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (88)
Die sicherheitstechnische Auslegung von Behältern aus duktilem Gusseisen mit erhöhten Reststoffanteilen wird untersucht. Ausgehend von den zu gewährleistenden Anforderungen an Transport- und Lagerbehälter für radioaktive Abfälle werden Referenzbeanspruchungs- situationen definiert. Für einen ausgewählten Referenzfall (bestehend aus der Kombination der Behälterbauart Gusscontainer Typ VI, einem Absturz aus 5 m Höhe auf ein hartes Endlagergestein simulierendes Betonfundament als repräsentativer Störfall und vorgegebenen Werkstoffeigenschaften) wird eine numerische Spannungsanalyse durchgeführt. Die Berechnungen erfolgen mit der Methode der finiten Elemente an dreidimensionalen Modellen, deren numerische Stabilität und Genauigkeit überprüft wird. Zur Berechnung der Behälterbeanspruchungen in Abhängigkeit vom Reststoffanteil werden dynamische Fließkurven für definiert legierte Testabgüsse angegeben.
Cylindrical casks made of ductile cast iron are used for transport, interim storage and final disposal of radioactive waste in Germany. A basic design criterion is the ability to withstand a horizontal drop without impact Binders onto a foundation representative for the real ground of a storage facility. The increasing use of more cost-effective material compositions requires optimized cask geometries to reduce stresses and strains in the cask structure. For example, a non-uniform wall thickness was introduced to reduce maximum wall bending stresses. As a result, the load characteristics changed from line load to point load at bottom and lid side under horizontal drop fest conditions. Hereby, the position of highest stress inside the structure has shifted significantly. This was the reason for a systematic investigation of effects caused by small design changes or small variations of fest conditions. It led to a better understanding of the positions of high local stresses, their time history and maximum value for cylindrical casks under horizontal drop test conditions. Hence, the paper presents the lessons learnt from modeling and simulating such scenarios considering an impact without limiters onto a realistic target.
Internationale Entwicklungen zur langfristig sicheren Zwischenlagerung bestrahlter Brennelemente
(2012)
Within the framework of the G8 partnership, the German Ministry of Economics and Technology has been realizing a 300 EUR million project of the storage of decommissioned Russian nuclear submarines based on a German-Russian agreement. The main parts of the project are the construction of the long-term storage facility as well as a radioactive waste storage facility at Sayda Bay. Long-term interim storage facility for this particular case has a period of about 70 years. The Energiewerke Nord GmbH (EWN) under the technical controlling of BAM carried out the project management. Foremost in this presentation is the finalization of the long-term storage facility for nuclear submarine compartments and the planning and realization of the radioactive waste storage building with special emphases of the parts carried out by BAM. Because BAM staff cannot stay permanently on site, a random inspection of different topics was the bases for the activities of BAM. The key aspects of activities are the long-term storage of the nuclear compartments, maintenance building, the decommissioning of the compartments and the transportation of the very heavy weight compartments (1600 metric tons). Details relating of the progress of the construction work as well as information about technical recommendations will also be briefly illustrated. Within this scope, problems and difficulties during the construction of the storage facility as well as logistical challenges including transportation of the reactor compartments will also be discussed.
Sicherheitsbewertung von Lagerbehältern bei Auslaufen einer befristeten Zwischenlagergenehmigung
(2013)
Bei der sicherheitstechnischen Begutachtung der behälterspezifischen Aspekte nach Ablauf einer Zwischenlagergenehmigung ist entsprechend einer Neubeantragung zu verfahren. Die Sicherheitsbewertung erfolgt nach dem aktuellen Stand von Wissenschaft und Technik bei Berücksichtigung der zur Behälterbauart bereits vorliegenden Sicherheitsnachweise und Begutachtungsergebnisse sowie der physikalischen und chemischen Alterungseinflüsse der bisherigen Zwischenlagerung. Am Beispiel einer beantragten weiteren Zwischenlagerung nach Auslaufen einer auf 20 Jahre befristeten Genehmigung und dem notwendigen Behältertransport zu einem neuen Zwischenlager werden Erfahrungen bzgl. der durchgeführten Sicherheitsbewertung zur Erfüllung der Technischen Annahmebedingungen des neuen Behälterlagers dargestellt.
An extensive series of large deformation crushing tests with spruce wood specimens was conducted. Material orientation, lateral constraint and loading rate were varied. Regarding material orientation, a reduction in the softening effect and the general force level was observed with a higher fiber-load angle. A comparison with characteristics gained by application of Hankinson's formula showed discrepancies in compression strength and the beginning of the hardening effect. Lateral constraint of the specimens caused a multiaxial stress state in the specimens, which was quantified with the applied measuring method. Further, a higher force level compared to specimens without lateral constraint and significant hardening effect at large deformations resulted. Thus, the influence of a multiaxial stress state on the force level could be determined. An increase in the loading rate led to higher force levels at any displacement value and material orientation.
In Deutschland werden zwei Arten von radioaktiven Abfällen unterschieden: Wärme entwickelnde Abfälle und Abfälle mit vernachlässigbarer Wärmeentwicklung. Im Endlager Konrad werden ausschließlich radioaktive Abfälle mit vernachlässigbarer Wärmeentwicklung endgelagert (im internationalen Sprachgebrauch: schwach- und mittelradioaktive Abfälle). Solche Abfälle stammen zum Beispiel aus dem laufenden Betrieb, der Stilllegung und dem Rückbau von Kernkraftwerken, aus der Forschung, der Medizin oder von der Bundeswehr und beinhalten unter anderem kontaminierte Baustoffe, Schrott, Werkzeuge, Schutzkleidung, Schlämme und Suspensionen. Vor dem Endlagern dieser Abfälle werden sie konditioniert, d. h. die festen Abfälle werden teilweise zerkleinert, verpresst oder zementiert, flüssige eingedampft oder zementiert und häufig anschließend in Fässer verpackt. Im nächsten Schritt werden die konditionierten Abfälle in Abfallbehälter verpackt. Geeignete Behältertypen sind (gemäß IM, 121) kubische Container oder Rundbehälter mit definierten Abmaßen aus Stahlblech, Beton oder Gusseisen. Diese Abfallbehälter sind für die Endlagerung, für eine vorausgehende längerfristige Zwischenlagerung sowie ggf. für den Transport über öffentliche Verkehrswege zu qualifizieren.
Experimental and numerical studies of shock absorbing materials for containers for radioactive waste
(2012)
BAM is the responsible authority in Germany for the assessment of the mechanical and thermal design safety of packages for the transport of radioactive materials. The assessment has to cover the proof of brittle fracture safety for package components made of potentially brittle materials. This paper gives a survey of the regulatory and technical requirements for such an assessment according to BAM's new 'Guidelines for the application of ductile cast iron for transport and storage casks for radioactive materials'. Based on these guidelines, higher stresses than before will be permissible, but it is necessary to put more effort into the safety assessment procedure. The fundamentals of such a proof using the methods of fracture mechanics are presented. The recommended procedure takes into account the guidelines of the IAEA's advisory material which are based on the prevention of crack initiation. Examples of BAM's research and safety assessment practices are given. Recommendations for further developments towards package designs with higher acceptable stress levels will conclude the paper.
Die Koordinierungsstelle für Informationen zur Behälterabfertigung (KOBAF): Aufgaben und Erfahrungen
(2008)
Casks for the transport and storage of heat generating radioactive waste in Germany are normally provided with screwed lid systems, which are in most cases equipped with double jacket metal seals with an inner spring wire to provide long term resistance to the seal compression force. Preservation of the high sealing quality of those seals under operational and accidental stress conditions is essentially important to the safety of those casks. Relative displacements of the lid system surfaces caused by specific impact scenarios cannot be excluded and have to be evaluated with respect to a possible increase in the leakage rate.
To get representative data for such metal sealed lid systems, BAM has developed a special conceptualised flange system placed in an appropriate testing machine for relevant mechanical loading of the metal seals under static and cyclic conditions. Furthermore, the flange system enables continuous measurement of the standard helium leakage rate during each test.
The primary aim of the investigation is to identify the correlation between variation of installation conditions (axial displacements) caused by external loads and the standard helium leakage rate. An essential parameter in this case is the useable resilience ru of a metal seal under relevant stress conditions. The useable resilience ru is the vertical difference in the cross-section between the seal's assembling status and the point where the leakage rate, by means of external load relieving, exceeds the quality criterion of 10-8 Pa m3 s-1. Load relieving can instantly occur due to modification of the seal groove dimension caused by accident impacts and deformation of the lid system. Furthermore, component specific basis data for the development of finite element calculation models should be collected. In the tests, seals are subjected to static and cyclic loads. All tests are performed at ambient temperature.
This paper presents the test configuration, different test series and results of the current experiments. Typical load-displacement-leakage rate correlations are presented and discussed.