The site continues to host a single international experiment measuring water leakage through a massive clay plug.
The fact that high-grade nuclear fuel was held in such formations for billions of years in nature was especially attractive; such deposits, like at Cigar Lake in northern Saskatchewan, were powerful evidence that this mode of storage was secure for geological time frames.
Organized by the Atomic Energy Control Board (AECB), AECL was tasked with developing the required technology, while Ontario Hydro would pay for the actual storage and be responsible for transport of the waste to and from a production site.
[2] Building the underground portion in the Canadian Shield eliminated concerns about geological events exposing the waste en masse; it is easy to find large batholiths that have been intact for billions of years.
However, these also include fractures of various sizes and the nature of water movement through these sorts of rock formation was a topic of limited research.
[4] Whiteshell, built on top of the 1400 km2 2.6 BYa Lac du Bonnet batholith,[5] was asked to find a suitable site.
The criterion was that there was at least one square kilometre of partially exposed rock on the surface, that it had not previously been used for excavation, that there was power available, and that it was within reasonable distance of Whiteshell.
Some of these involved measurements of the flow of water in the various rock formations, while others were concerned with the engineered seals and container technologies.
Although they found some concerns in the research, the AECB decided enough was known to move ahead to begin selecting a production repository site.
[8] The ultimate result of the URL was a ten-volume Environmental Impact Statement about the entire deep geologic repository concept.