Conceptual uncertainties in modelling the interaction between engineered and natural barriers of nuclear waste repositories in crystalline rocks

S. Finsterle, B. Lanyon, M. Åkesson, S. Baxter, M. Bergström, N. Bockgård, W. Dershowitz, B. Dessirier, A. Frampton, Å. Fransson, A. Gens, B. Gylling, I. Hančilová, D. Holton, J. Jarsjö, J.-S. Kim, K.-P. Kröhn, D. Malmberg, Veli-Matti Pulkkanen, A. Sawada & 4 others A. Sjöland, U. Svensson, P. Vidstrand, H. Viswanathan

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Nuclear waste disposal in geological formations relies on a multi-barrier concept that includes engineered components – which, in many cases, include a bentonite buffer surrounding waste packages – and the host rock. Contrasts in materials, together with gradients across the interface between the engineered and natural barriers, lead to complex interactions between these two subsystems. Numerical modelling, combined with monitoring and testing data, can be used to improve our overall understanding of rock–bentonite interactions and to predict the performance of this coupled system. Although established methods exist to examine the prediction uncertainties due to uncertainties in the input parameters, the impact of conceptual model decisions on the quantitative and qualitative modelling results is more difficult to assess. A Swedish Nuclear Fuel and Waste Management Company Task Force project facilitated such an assessment. In this project, 11 teams used different conceptualizations and modelling tools to analyse the Bentonite Rock Interaction Experiment (BRIE) conducted at the Äspö Hard Rock Laboratory in Sweden. The exercise showed that prior system understanding along with the features implemented in the available simulators affect the processes included in the conceptual model. For some of these features, sufficient characterization data are available to obtain defensible results and interpretations, whereas others are less supported. The exercise also helped to identify the conceptual uncertainties that led to different assessments of the relative importance of the engineered and natural barrier subsystems. The range of predicted bentonite wetting times encompassed by the ensemble results were considerably larger than the ranges derived from individual models. This is a consequence of conceptual uncertainties, demonstrating the relevance of using a multi-model approach involving alternative conceptualizations.
Original languageEnglish
JournalGeological Society Special Publication
Issue number482
DOIs
Publication statusPublished - 7 Dec 2018
MoE publication typeNot Eligible

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Crystalline rocks
natural barrier
crystalline rock
Radioactive wastes
repository
radioactive waste
Bentonite
bentonite
Rocks
modeling
Nuclear fuels
hard rock
Waste management
Waste disposal
wetting
waste disposal
host rock
waste management
simulator
Wetting

Cite this

Finsterle, S. ; Lanyon, B. ; Åkesson, M. ; Baxter, S. ; Bergström, M. ; Bockgård, N. ; Dershowitz, W. ; Dessirier, B. ; Frampton, A. ; Fransson, Å. ; Gens, A. ; Gylling, B. ; Hančilová, I. ; Holton, D. ; Jarsjö, J. ; Kim, J.-S. ; Kröhn, K.-P. ; Malmberg, D. ; Pulkkanen, Veli-Matti ; Sawada, A. ; Sjöland, A. ; Svensson, U. ; Vidstrand, P. ; Viswanathan, H. / Conceptual uncertainties in modelling the interaction between engineered and natural barriers of nuclear waste repositories in crystalline rocks. In: Geological Society Special Publication. 2018 ; No. 482.
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abstract = "Nuclear waste disposal in geological formations relies on a multi-barrier concept that includes engineered components – which, in many cases, include a bentonite buffer surrounding waste packages – and the host rock. Contrasts in materials, together with gradients across the interface between the engineered and natural barriers, lead to complex interactions between these two subsystems. Numerical modelling, combined with monitoring and testing data, can be used to improve our overall understanding of rock–bentonite interactions and to predict the performance of this coupled system. Although established methods exist to examine the prediction uncertainties due to uncertainties in the input parameters, the impact of conceptual model decisions on the quantitative and qualitative modelling results is more difficult to assess. A Swedish Nuclear Fuel and Waste Management Company Task Force project facilitated such an assessment. In this project, 11 teams used different conceptualizations and modelling tools to analyse the Bentonite Rock Interaction Experiment (BRIE) conducted at the {\"A}sp{\"o} Hard Rock Laboratory in Sweden. The exercise showed that prior system understanding along with the features implemented in the available simulators affect the processes included in the conceptual model. For some of these features, sufficient characterization data are available to obtain defensible results and interpretations, whereas others are less supported. The exercise also helped to identify the conceptual uncertainties that led to different assessments of the relative importance of the engineered and natural barrier subsystems. The range of predicted bentonite wetting times encompassed by the ensemble results were considerably larger than the ranges derived from individual models. This is a consequence of conceptual uncertainties, demonstrating the relevance of using a multi-model approach involving alternative conceptualizations.",
author = "S. Finsterle and B. Lanyon and M. {\AA}kesson and S. Baxter and M. Bergstr{\"o}m and N. Bockg{\aa}rd and W. Dershowitz and B. Dessirier and A. Frampton and {\AA}. Fransson and A. Gens and B. Gylling and I. Hančilov{\'a} and D. Holton and J. Jarsj{\"o} and J.-S. Kim and K.-P. Kr{\"o}hn and D. Malmberg and Veli-Matti Pulkkanen and A. Sawada and A. Sj{\"o}land and U. Svensson and P. Vidstrand and H. Viswanathan",
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Finsterle, S, Lanyon, B, Åkesson, M, Baxter, S, Bergström, M, Bockgård, N, Dershowitz, W, Dessirier, B, Frampton, A, Fransson, Å, Gens, A, Gylling, B, Hančilová, I, Holton, D, Jarsjö, J, Kim, J-S, Kröhn, K-P, Malmberg, D, Pulkkanen, V-M, Sawada, A, Sjöland, A, Svensson, U, Vidstrand, P & Viswanathan, H 2018, 'Conceptual uncertainties in modelling the interaction between engineered and natural barriers of nuclear waste repositories in crystalline rocks', Geological Society Special Publication, no. 482. https://doi.org/10.1144/SP482.12

Conceptual uncertainties in modelling the interaction between engineered and natural barriers of nuclear waste repositories in crystalline rocks. / Finsterle, S.; Lanyon, B.; Åkesson, M.; Baxter, S.; Bergström, M.; Bockgård, N.; Dershowitz, W.; Dessirier, B.; Frampton, A.; Fransson, Å.; Gens, A.; Gylling, B.; Hančilová, I.; Holton, D.; Jarsjö, J.; Kim, J.-S.; Kröhn, K.-P.; Malmberg, D.; Pulkkanen, Veli-Matti; Sawada, A.; Sjöland, A.; Svensson, U.; Vidstrand, P.; Viswanathan, H.

In: Geological Society Special Publication, No. 482, 07.12.2018.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Conceptual uncertainties in modelling the interaction between engineered and natural barriers of nuclear waste repositories in crystalline rocks

AU - Finsterle, S.

AU - Lanyon, B.

AU - Åkesson, M.

AU - Baxter, S.

AU - Bergström, M.

AU - Bockgård, N.

AU - Dershowitz, W.

AU - Dessirier, B.

AU - Frampton, A.

AU - Fransson, Å.

AU - Gens, A.

AU - Gylling, B.

AU - Hančilová, I.

AU - Holton, D.

AU - Jarsjö, J.

AU - Kim, J.-S.

AU - Kröhn, K.-P.

AU - Malmberg, D.

AU - Pulkkanen, Veli-Matti

AU - Sawada, A.

AU - Sjöland, A.

AU - Svensson, U.

AU - Vidstrand, P.

AU - Viswanathan, H.

PY - 2018/12/7

Y1 - 2018/12/7

N2 - Nuclear waste disposal in geological formations relies on a multi-barrier concept that includes engineered components – which, in many cases, include a bentonite buffer surrounding waste packages – and the host rock. Contrasts in materials, together with gradients across the interface between the engineered and natural barriers, lead to complex interactions between these two subsystems. Numerical modelling, combined with monitoring and testing data, can be used to improve our overall understanding of rock–bentonite interactions and to predict the performance of this coupled system. Although established methods exist to examine the prediction uncertainties due to uncertainties in the input parameters, the impact of conceptual model decisions on the quantitative and qualitative modelling results is more difficult to assess. A Swedish Nuclear Fuel and Waste Management Company Task Force project facilitated such an assessment. In this project, 11 teams used different conceptualizations and modelling tools to analyse the Bentonite Rock Interaction Experiment (BRIE) conducted at the Äspö Hard Rock Laboratory in Sweden. The exercise showed that prior system understanding along with the features implemented in the available simulators affect the processes included in the conceptual model. For some of these features, sufficient characterization data are available to obtain defensible results and interpretations, whereas others are less supported. The exercise also helped to identify the conceptual uncertainties that led to different assessments of the relative importance of the engineered and natural barrier subsystems. The range of predicted bentonite wetting times encompassed by the ensemble results were considerably larger than the ranges derived from individual models. This is a consequence of conceptual uncertainties, demonstrating the relevance of using a multi-model approach involving alternative conceptualizations.

AB - Nuclear waste disposal in geological formations relies on a multi-barrier concept that includes engineered components – which, in many cases, include a bentonite buffer surrounding waste packages – and the host rock. Contrasts in materials, together with gradients across the interface between the engineered and natural barriers, lead to complex interactions between these two subsystems. Numerical modelling, combined with monitoring and testing data, can be used to improve our overall understanding of rock–bentonite interactions and to predict the performance of this coupled system. Although established methods exist to examine the prediction uncertainties due to uncertainties in the input parameters, the impact of conceptual model decisions on the quantitative and qualitative modelling results is more difficult to assess. A Swedish Nuclear Fuel and Waste Management Company Task Force project facilitated such an assessment. In this project, 11 teams used different conceptualizations and modelling tools to analyse the Bentonite Rock Interaction Experiment (BRIE) conducted at the Äspö Hard Rock Laboratory in Sweden. The exercise showed that prior system understanding along with the features implemented in the available simulators affect the processes included in the conceptual model. For some of these features, sufficient characterization data are available to obtain defensible results and interpretations, whereas others are less supported. The exercise also helped to identify the conceptual uncertainties that led to different assessments of the relative importance of the engineered and natural barrier subsystems. The range of predicted bentonite wetting times encompassed by the ensemble results were considerably larger than the ranges derived from individual models. This is a consequence of conceptual uncertainties, demonstrating the relevance of using a multi-model approach involving alternative conceptualizations.

U2 - 10.1144/SP482.12

DO - 10.1144/SP482.12

M3 - Article

JO - Geological Society Special Publication

JF - Geological Society Special Publication

SN - 0305-8719

IS - 482

ER -