We have established that a low-level repository could be constructed at reasonable cost, provide you have tight rock. Going to Paleocollapse rock, will cost you billions more. One of the best places to locate this would be Waterloo, where you could also bury the radioactive remains of RIM. :)
High level waste requires granite because of the heat. Only loonies would try to put this in soft rock, but I expect this attempt soon. As a result of my studies, it has become clear that you cannot use exposed Precambrian granite (or even the older stuff). This rock has been exposed to numerous glaciations, and hydrofracking has nothing on the water pressures associated with kilometres of ice. This water has been injected into the rock, causing huge sub-horizontal fractures that are as open as Miley's dress.
The best rock is granite that has been overlain by tight, impermeable limestones and shales. This is the type of rock that we drilled at Darlington, but it can be found anywhere, even Waterloo! It is important not to be right on the hanging wall of the megathrusts. I think London, Ontario would be perfect, as I could never figure out why anybody would want to live there. :)
Strong, tight granites most likely have enormous horizontal stresses. When they were playing around with a mock-up repository up in Manitoba, they encountered this type of rock, which explosively fractures into disks when you drill it. Normally you might think to stay away from this rock, but there is sufficient mining experience to know how to handle it.
-to be continued.