That sort of funding is usually directed towards a research group, which is led by a supervisor, and the supervisors will then allocate those funds as they can. Unlike general graduate scholarships, however, those funds, at least in my experience and to the best of my knowledge, are very often used directly for research purposes. They can't be allocated to graduate students for general spending or personal spending.
The NWMO is very active with my research group because a big part of our research looks at nuclear waste. Much of our funding comes from them, but none of it is allocated to the students outside of research-related purposes.