Investigation of potential water inflow into a ventilated tunnel of the proposed low/intermediate-level waste repository in Switzerland
- Swiss Federal Institute of Technology, Zurich (Switzerland)
- INTERA Inc., Austin, TX (United States)
Design calculations of two-phase flow phenomena associated with the construction and ventilation of a tunnel were investigated to estimate the potential water inflow through discrete water-conducting features (WCFs) into the tunnel. The physical processes that were considered in numerical simulations include the transient propagation of the pressure decline into the formation (Valanginian Marl, initially fully saturated, no dissolved gas) as a result of the tunnel construction. Ventilation of the tunnel results in a reduction in relative humidity of the tunnel air which, in turn, causes evaporation of water at the tunnel wall and the potential development of an unsaturated zone into the formation. The objective of this study is to investigate under what conditions the tunnel wall appears wet or dry, i.e. whether WCFs can be identified in a ventilated tunnel by mapping water inflow patterns. The simulation results indicate that inflow to the tunnel decreases with time approaching steady state flow rates under single-phase flow conditions, which is lower than the evaporation rate. The water inflow rate decreased more rapidly for a first model scenario (WCF parallel to the tunnel axis), caused by linear flow through the WCF, than for a second model scenario (WCF perpendicular to the tunnel axis), characterized by radial flow toward the tunnel. Similarly, the desaturation zone extends farther into the WCF under linear flow than under radial flow.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 107162
- Report Number(s):
- LBL-37200; CONF-9503110-; ON: DE95014788; TRN: 95:006737-0002
- Resource Relation:
- Conference: TOUGH 95: transport of unsaturated ground water and heat workshop, Berkeley, CA (United States), 20-22 Mar 1995; Other Information: PBD: Mar 1995; Related Information: Is Part Of Proceedings of the TOUGH Workshop `95 Lawrence Berkeley Laboratory, Berkeley, California, March 20--22, 1995; Pruess, K. [ed.]; PB: 380 p.
- Country of Publication:
- United States
- Language:
- English
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