Simulation of hydraulic disturbances caused by the underground rock characterization facility in Olkiluoto, Finland

Jari Löfman, Ferenc Mészáros

    Research output: Chapter in Book/Report/Conference proceedingChapter or book articleProfessional

    1 Citation (Scopus)

    Abstract

    A final repository for spent nuclear fuel is sought in Finland by Posiva (a company responsible for the construction and operation of the final nuclear-waste disposal facility in Finland, http://www.posiva.fi). A part of this project involves an underground rock characterization facility (ONKALO), which will consist of an 8,500 m long and 520 m deep system of tunnels, to be potentially extended with the drifts of the repository. The maximum hydraulic disturbance (water table drawdown, deep saline-water upconing and tunnel inflow) that might result from the construction and operation of the ONKALO facility were assessed by site-scale finite-element simulations. The drawdown was calculated by employing the free-surface approach. Tunnel inflows were obtained from the state of equilibrium, while the evolution of the salinity distribution was simulated using a time-dependent and coupled flow and salt transport model. The simulations showed that without engineering measures to limit inflow of groundwater into the ONKALO facility, the hydraulic disturbances would be significantly greater than with these measures implemented. Most of the inflow (330-1,100 L/min) would come from the conductive subhorizontal fracture zones intersected by the drifts. The water table could sink to a depth of about 200 m, and the depressed area could extend over the Olkiluoto Island. Groundwater salinity (expressed as total dissolved solids [TDS]) could locally rise from 22 g/L to over 50 g/L at the tunnel depth of 520 m. With tight grouting, the simulations showed that the depression in the water table can be confined to the immediate vicinity of the ONKALO, the maximum drawdown of the water table remained around 10 m, and the total inflow to the tunnels was about 20 L/min. Moreover, upconing of the saline water remained moderate.
    Original languageEnglish
    Title of host publicationDynamics of Fluids and Transport in Fractured Rock
    EditorsBoris Faybishenko, John Gale, Paul A. Witherspoon
    Place of PublicationWashington, DC
    Pages129-149
    Volume162
    DOIs
    Publication statusPublished - 2005
    MoE publication typeD2 Article in professional manuals or guides or professional information systems or text book material

    Fingerprint

    inflow
    tunnel
    water table
    hydraulics
    disturbance
    drawdown
    rock
    simulation
    repository
    salinity
    groundwater
    grouting
    fracture zone
    waste disposal
    radioactive waste
    salt
    engineering
    water

    Cite this

    Löfman, J., & Mészáros, F. (2005). Simulation of hydraulic disturbances caused by the underground rock characterization facility in Olkiluoto, Finland. In B. Faybishenko, J. Gale, & P. A. Witherspoon (Eds.), Dynamics of Fluids and Transport in Fractured Rock (Vol. 162, pp. 129-149). Washington, DC. https://doi.org/10.1029/162GM13
    Löfman, Jari ; Mészáros, Ferenc. / Simulation of hydraulic disturbances caused by the underground rock characterization facility in Olkiluoto, Finland. Dynamics of Fluids and Transport in Fractured Rock. editor / Boris Faybishenko ; John Gale ; Paul A. Witherspoon. Vol. 162 Washington, DC, 2005. pp. 129-149
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    abstract = "A final repository for spent nuclear fuel is sought in Finland by Posiva (a company responsible for the construction and operation of the final nuclear-waste disposal facility in Finland, http://www.posiva.fi). A part of this project involves an underground rock characterization facility (ONKALO), which will consist of an 8,500 m long and 520 m deep system of tunnels, to be potentially extended with the drifts of the repository. The maximum hydraulic disturbance (water table drawdown, deep saline-water upconing and tunnel inflow) that might result from the construction and operation of the ONKALO facility were assessed by site-scale finite-element simulations. The drawdown was calculated by employing the free-surface approach. Tunnel inflows were obtained from the state of equilibrium, while the evolution of the salinity distribution was simulated using a time-dependent and coupled flow and salt transport model. The simulations showed that without engineering measures to limit inflow of groundwater into the ONKALO facility, the hydraulic disturbances would be significantly greater than with these measures implemented. Most of the inflow (330-1,100 L/min) would come from the conductive subhorizontal fracture zones intersected by the drifts. The water table could sink to a depth of about 200 m, and the depressed area could extend over the Olkiluoto Island. Groundwater salinity (expressed as total dissolved solids [TDS]) could locally rise from 22 g/L to over 50 g/L at the tunnel depth of 520 m. With tight grouting, the simulations showed that the depression in the water table can be confined to the immediate vicinity of the ONKALO, the maximum drawdown of the water table remained around 10 m, and the total inflow to the tunnels was about 20 L/min. Moreover, upconing of the saline water remained moderate.",
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    Löfman, J & Mészáros, F 2005, Simulation of hydraulic disturbances caused by the underground rock characterization facility in Olkiluoto, Finland. in B Faybishenko, J Gale & PA Witherspoon (eds), Dynamics of Fluids and Transport in Fractured Rock. vol. 162, Washington, DC, pp. 129-149. https://doi.org/10.1029/162GM13

    Simulation of hydraulic disturbances caused by the underground rock characterization facility in Olkiluoto, Finland. / Löfman, Jari; Mészáros, Ferenc.

    Dynamics of Fluids and Transport in Fractured Rock. ed. / Boris Faybishenko; John Gale; Paul A. Witherspoon. Vol. 162 Washington, DC, 2005. p. 129-149.

    Research output: Chapter in Book/Report/Conference proceedingChapter or book articleProfessional

    TY - CHAP

    T1 - Simulation of hydraulic disturbances caused by the underground rock characterization facility in Olkiluoto, Finland

    AU - Löfman, Jari

    AU - Mészáros, Ferenc

    PY - 2005

    Y1 - 2005

    N2 - A final repository for spent nuclear fuel is sought in Finland by Posiva (a company responsible for the construction and operation of the final nuclear-waste disposal facility in Finland, http://www.posiva.fi). A part of this project involves an underground rock characterization facility (ONKALO), which will consist of an 8,500 m long and 520 m deep system of tunnels, to be potentially extended with the drifts of the repository. The maximum hydraulic disturbance (water table drawdown, deep saline-water upconing and tunnel inflow) that might result from the construction and operation of the ONKALO facility were assessed by site-scale finite-element simulations. The drawdown was calculated by employing the free-surface approach. Tunnel inflows were obtained from the state of equilibrium, while the evolution of the salinity distribution was simulated using a time-dependent and coupled flow and salt transport model. The simulations showed that without engineering measures to limit inflow of groundwater into the ONKALO facility, the hydraulic disturbances would be significantly greater than with these measures implemented. Most of the inflow (330-1,100 L/min) would come from the conductive subhorizontal fracture zones intersected by the drifts. The water table could sink to a depth of about 200 m, and the depressed area could extend over the Olkiluoto Island. Groundwater salinity (expressed as total dissolved solids [TDS]) could locally rise from 22 g/L to over 50 g/L at the tunnel depth of 520 m. With tight grouting, the simulations showed that the depression in the water table can be confined to the immediate vicinity of the ONKALO, the maximum drawdown of the water table remained around 10 m, and the total inflow to the tunnels was about 20 L/min. Moreover, upconing of the saline water remained moderate.

    AB - A final repository for spent nuclear fuel is sought in Finland by Posiva (a company responsible for the construction and operation of the final nuclear-waste disposal facility in Finland, http://www.posiva.fi). A part of this project involves an underground rock characterization facility (ONKALO), which will consist of an 8,500 m long and 520 m deep system of tunnels, to be potentially extended with the drifts of the repository. The maximum hydraulic disturbance (water table drawdown, deep saline-water upconing and tunnel inflow) that might result from the construction and operation of the ONKALO facility were assessed by site-scale finite-element simulations. The drawdown was calculated by employing the free-surface approach. Tunnel inflows were obtained from the state of equilibrium, while the evolution of the salinity distribution was simulated using a time-dependent and coupled flow and salt transport model. The simulations showed that without engineering measures to limit inflow of groundwater into the ONKALO facility, the hydraulic disturbances would be significantly greater than with these measures implemented. Most of the inflow (330-1,100 L/min) would come from the conductive subhorizontal fracture zones intersected by the drifts. The water table could sink to a depth of about 200 m, and the depressed area could extend over the Olkiluoto Island. Groundwater salinity (expressed as total dissolved solids [TDS]) could locally rise from 22 g/L to over 50 g/L at the tunnel depth of 520 m. With tight grouting, the simulations showed that the depression in the water table can be confined to the immediate vicinity of the ONKALO, the maximum drawdown of the water table remained around 10 m, and the total inflow to the tunnels was about 20 L/min. Moreover, upconing of the saline water remained moderate.

    U2 - 10.1029/162GM13

    DO - 10.1029/162GM13

    M3 - Chapter or book article

    SN - 0-87590-427-0

    SN - 978-0-875-90427-6

    VL - 162

    SP - 129

    EP - 149

    BT - Dynamics of Fluids and Transport in Fractured Rock

    A2 - Faybishenko, Boris

    A2 - Gale, John

    A2 - Witherspoon, Paul A.

    CY - Washington, DC

    ER -

    Löfman J, Mészáros F. Simulation of hydraulic disturbances caused by the underground rock characterization facility in Olkiluoto, Finland. In Faybishenko B, Gale J, Witherspoon PA, editors, Dynamics of Fluids and Transport in Fractured Rock. Vol. 162. Washington, DC. 2005. p. 129-149 https://doi.org/10.1029/162GM13