Uncertainty in numerical models of borehole heat exchangers

Rühaak, W.; Steiner, Sarah; Welsch, Bastian; Sass, Ingo

doi:10.1007/s00767-015-0305-9

Cited by 4 publications

(2 citation statements)

References 11 publications

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“…Since this knowledge about the subsurface is based on different data, e.g., data from mapping, drillings or seismic explorations, it involves uncertainties due to resolution, measurement errors, etc. These uncertainties have been addressed in different studies by, e.g., Rühaak et al (2015), Wellmann and Caumon (2018) or Wellmann et al (2010). With a view to the disposal of nuclear waste, this leads to the following questions: How do uncertainties in geometry affect the respective TM behavior of the rock?…”

Section: Introductionmentioning

confidence: 99%

The role of geological models and uncertainties in safety assessments

Bjorge¹,

Kreye²,

Heim

et al. 2022

Environ Earth Sci

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Safety assessments in nuclear waste management typically include the analysis of thermo-mechanical (TM)-coupled processes. The TM behavior of the host rock is, among other aspects, dependent on the prevalent geological geometry. This study aims to evaluate the impact of uncertainties in geometry on the TM rock behavior. It is one of the very first studies aiming to bring uncertainties of structural geological models and numerical simulations together. To analyze the influence of geological geometries, a simplified model of the region around the Mont Terri rock laboratory was created. A 3D structural geological model was set up and uncertainties of the lithological contacts were quantified by means of stochastic simulations, resulting in an ensemble of 89 model realizations. These realizations were transformed to a 2D numerical model. In this numerical model, TM simulations were computed over a simulation time of 500 years, employing the Finite Element Method. To simulate a heat source of nuclear waste, the lower edge of the model was set to 100 °C. The results of these simulations show mean temperature variations of 90.89 and 92.70 °C after 500 years, with a maximum stress varying between 0.02 and 0.16 MPa of elastic shear energy density and according mean cumulative displacements ranging from 30 to 38 cm. The presented results indicate that different model geometries and differences in material properties lead to noticeable variabilities of the TM behavior of claystone. However, in this case, these variabilities would not significantly affect the integrity of the rock.

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Section: Introductionmentioning

confidence: 99%

The role of geological models and uncertainties in safety assessments

Bjorge¹,

Kreye²,

Heim

et al. 2022

Environ Earth Sci

Self Cite

View full text Add to dashboard Cite

show abstract

“…These uncertainties have been addressed in different studies by e.g. Rühaak et al (2015), Wellmann & Caumon (2018) or Wellmann et al (2010). With a view to the disposal of nuclear waste this leads to the following questions: How do uncertainties in geometry affect the respective TM-behavior of the rock?…”

Section: Introductionmentioning

confidence: 99%

The Role of Geological Models and Uncertainties in Safety Assessments

Bjorge¹,

Kreye²,

Heim

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Safety assessments in nuclear waste management typically include the analysis of thermo-mechanical (TM) coupled processes. The TM behavior of the host rock is, amongst other aspects, dependent on the prevalent geological geometry. This study aims to evaluate the impact of uncertainties in geometry on the TM rock behavior. It is one of the very first studies aiming to bring uncertainties of structural geological models and numerical simulations together.To analyze the influence of geological geometries, a simplified model of the region around the Mont Terri rock laboratory was created. A 3-D structural geological model was set up and uncertainties of the lithological contacts were quantified by means of stochastic simulations, resulting in an ensemble of 89 model realizations. These realizations were transformed to a 2-D numerical model. In this numerical model, TM simulations were computed over a simulation time of 500 years, employing the Finite Element Method. To simulate a heat source of nuclear waste the lower edge of the model was set to 100°C.The results of these simulations show mean temperature variations of 90.89 °C and 92.70 ° after 500 years, with a maximum stress varying between 0.02 MPa and 0.16 MPa of elastic shear energy density and according mean cumulative displacements ranging from 30 cm to 38 cm. The presented results indicate that different model geometries and differences in material properties lead to noticeable variabilities of the TM behavior of claystone. However in this case, these variabilities would not significantly affect the integrity of the rock.

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Numerische Modelle in Sicherheitsuntersuchungen für die Endlagersuche: Möglichkeiten und Grenzen

Behrens,

Bjorge,

Renz

et al. 2024

Grundwasser - Zeitschrift der Fachsektion Hydrogeologie

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ZusammenfassungFür die Durchführung von Sicherheitsuntersuchungen im Rahmen des deutschen Standortauswahlverfahrens zur Suche nach einem Endlager für hochradioaktive Abfälle sind numerische Modelle ein wichtiges Instrument. Ihr Anwendungsbereich ist vielfältig und umfasst zum Beispiel Fragestellungen zur thermischen Auslegung des Endlagers und des potenziellen Austrags radioaktiver Stoffe aus der Geosphäre.Numerische Modelle werden in vielen Branchen nutzbringend eingesetzt. Allerdings hat die Aussagekraft von Modellen immer auch Grenzen. Von entscheidender Bedeutung ist es daher, die grundsätzlichen Möglichkeiten und Grenzen des Einsatzes von Modellen zu verstehen und zu berücksichtigen.Die Auswahl und das Design geeigneter, aussagekräftiger Modelle sind komplexe Aufgaben und können immer nur bezugnehmend auf den konkreten Fall erfolgen: Ein „Patentrezept“ gibt es nicht. Dennoch gibt es grundlegende Leitsätze, die in der Praxis eine große Rolle spielen. Wir erläutern einige dieser Grundsätze und untersuchen kritisch, inwieweit sie anwendbar sind und wo ihre Limitationen liegen.

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Uncertainty in numerical models of borehole heat exchangers

Cited by 4 publications

References 11 publications

The role of geological models and uncertainties in safety assessments

The role of geological models and uncertainties in safety assessments

The Role of Geological Models and Uncertainties in Safety Assessments

Numerische Modelle in Sicherheitsuntersuchungen für die Endlagersuche: Möglichkeiten und Grenzen

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