- Within the safety concepts of underground disposal sites of nuclear waste, engineered barriers play an important role. As these sealing structures have high demands concerning integrity, we aim at advancing the available construction materials, monitoring, and inspection techniques within the project SealWasteSafe. A specifically developed alkali-activated material is compared to classical salt concrete. A comprehensive multi-sensory monitoring scheme is used at 150-340 l specimens to monitor setting and hardening of both materials. All sensors are demonstrated to resist the highly alkaline environments. Besides cabled and wireless temperature and humidity of the materials, strain variations using fibre optic sensors and acoustic emissions are recorded over periods of at least 28 days, partly for more than eight months. After hardening of the specimens, further nondestructive evaluations using ultrasonic echo and thermographic measurements are conducted.
Preliminary results proof theWithin the safety concepts of underground disposal sites of nuclear waste, engineered barriers play an important role. As these sealing structures have high demands concerning integrity, we aim at advancing the available construction materials, monitoring, and inspection techniques within the project SealWasteSafe. A specifically developed alkali-activated material is compared to classical salt concrete. A comprehensive multi-sensory monitoring scheme is used at 150-340 l specimens to monitor setting and hardening of both materials. All sensors are demonstrated to resist the highly alkaline environments. Besides cabled and wireless temperature and humidity of the materials, strain variations using fibre optic sensors and acoustic emissions are recorded over periods of at least 28 days, partly for more than eight months. After hardening of the specimens, further nondestructive evaluations using ultrasonic echo and thermographic measurements are conducted.
Preliminary results proof the suitability of the tested sensors and clearly highlight differences between the tested materials. Particularly, the newly developed alkali-activated material shows lower acoustic emission activity indicating less cracking activity. Additionally, unique ultrasonic methods will enable better images of potential internal objects and cracks at in-situ sealing structures. A largescale ultrasonic system is optimised to reliably detect objects at a depth exceeding 9 m while still obtaining a good resolution. Modelling studies show the potential of further increasing the distance between individual transducer arrays. Additionally, a new ultrasonic borehole probe using phased arrays allowing for beam focussing is constructed and tested. Laboratory measurements at a halfcylindrical concrete specimen coincide well with the previous modelling. In total, the presented safe materials, detailed monitoring approaches and ultrasonic quality assurance methods will help to obtain safe sealing structures within salt as a host rock. The concepts can partly be transferred to sealing structures in alternative host rocks and will also be valuable for non-nuclear waste repositories.…
MetadatenAutor*innen: | Vera LayORCiD, Frank Mielentz, Prathik Prabhakara, Franziska BaenschORCiD, Sergej Johann, Detlef Hofmann, Patrick Sturm, Michael Stamm, Ernst NiederleithingerORCiD |
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Dokumenttyp: | Beitrag zu einem Tagungsband |
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Veröffentlichungsform: | Graue Literatur |
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Sprache: | Englisch |
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Titel des übergeordneten Werkes (Englisch): | Proceedings of the International Conference on Non-destructive Evaluation of Concrete in Nuclear Applications |
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Jahr der Erstveröffentlichung: | 2023 |
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Organisationseinheit der BAM: | 7 Bauwerkssicherheit |
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| 7 Bauwerkssicherheit / 7.4 Baustofftechnologie |
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| 8 Zerstörungsfreie Prüfung |
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| 8 Zerstörungsfreie Prüfung / 8.1 Sensorik, mess- und prüftechnische Verfahren |
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| 8 Zerstörungsfreie Prüfung / 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen |
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| 8 Zerstörungsfreie Prüfung / 8.3 Thermografische Verfahren |
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| 8 Zerstörungsfreie Prüfung / 8.6 Faseroptische Sensorik |
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Erste Seite: | 2 |
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Letzte Seite: | 10 |
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DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik |
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Freie Schlagwörter: | Embedded sensors; Engineered barriers; Monitoring; SealWasteSafe; Ultrasonic imaging |
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Themenfelder/Aktivitätsfelder der BAM: | Energie |
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| Energie / Kerntechnische Entsorgung |
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Veranstaltung: | NDE NucCon |
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Veranstaltungsort: | Espoo, Finland |
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Beginndatum der Veranstaltung: | 25.01.2023 |
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Enddatum der Veranstaltung: | 27.01.2023 |
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Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
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Datum der Freischaltung: | 01.02.2023 |
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Referierte Publikation: | Nein |
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