Conceptual uncertainties in modelling the interaction between engineered and natural barriers of nuclear waste repositories in crystalline rocks
Artikel i vetenskaplig tidskrift, 2019

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.

Författare

S. Finsterle

Finsterle GeoConsulting

B. Lanyon

Fracture Systems Ltd

M. Åkesson

Clay Technology AB

S. Baxter

Wood Group

M. Bergström

Golder Associates AB

N. Bockgård

Golder Associates AB

W. Dershowitz

Golder Associates Inc, USA

B. Dessirier

Stockholms universitet

Uppsala universitet

A. Frampton

Stockholms universitet

Åsa Fransson

Chalmers, Arkitektur och samhällsbyggnadsteknik, Geologi och geoteknik

A. Gens

Universitat Politecnica de Catalunya

Björn Gylling

Svensk Kärnbränslehantering (SKB)

I. Hancǐlová

Technická univerzita v Liberci

D. Holton

Wood Group

Jerker Jarsjö

Stockholms universitet

J. S. Kim

Korea Atomic Energy Research Institute

K. P. Kröhn

Gesellschaft fur Anlagen- und Reaktorsicherheit mbH

D. Malmberg

Clay Technology AB

V. M. Pulkkanen

Teknologian Tutkimuskeskus (VTT)

A. Sawada

Japan Atomic Energy Agency

A. Sjöland

Svensk Kärnbränslehantering (SKB)

U. Svensson

Computer-aided Fluid Engineering AB

P. Vidstrand

Svensk Kärnbränslehantering (SKB)

H. Viswanathan

Los Alamos National Laboratory

Geological Society Special Publication

0305-8719 (ISSN)

Vol. 482 1 261-283

Ämneskategorier

Geofysisk teknik

Rymd- och flygteknik

Geoteknik

DOI

10.1144/SP482.12

Mer information

Senast uppdaterat

2020-01-09