Underground Research Laboratory (URL)
The Underground Research Laboratory (URL) is a research facility owned and operated by Atomic Energy of Canada Ltd (AECL), a branch of Ontario Hydro. The purpose of the URL is to study the feasibility of safe disposal of nuclear fuel in a stable excavation in a low permeability rock mass.
The URL is located in the Lac du Bonnet granite batholith located in Pinawa, Manitoba, Canada. Tunnels at the URL extend to depths of 440 m below the surface. The major stress at this depth is sub-horizontal and the ratio of maximum to minumum stress is about 5:1. This high stress ratio demands intelligent engineering solutions to prevent major damage in areas of high stress concentration around deep excavations. Microseismic and acoustic emission monitoring as well as ultrasonic velocity measurements made by the Applied Seismology Laboratory help delineate and quanitfy the damage, which is important for observing possible routes for the transport of radionucleides into the surrounding groundwater.
Two major experiments at the URL are:
1. Mine-by Experiment
A project to examine the excavation induced damage around a cylindrical tunnel.
2. Tunnel Sealing Experiment
A project to observe the integrity of different sealing technologies in a tunnel subjected to high hydraulic pressures.