Canada’s Ontario Power Generation (OPG) said on 5 January that relocating a proposed deep geologic repository for low- and intermediate-level radioactive waste from the Bruce NPP site in Ontario to an alternative location would probably have a greater environmental effect including increased impact on air quality, land use, vegetation and wildlife.

In documents submitted to the Canadian Environmental Assessment Agency, OPG said it would entail an estimated 22,000-24,000 road shipments over 30 years at an estimated incremental cost of up to CAD$1.4bn ( $1bn). There would also be incremental radiological and conventional transportation risks, OPG said. Other incremental project costs of up to $2.1bn would include   site characterisation of an alternative location, regulatory approvals, and site preparation and infrastructure development.

OPG noted that there would be considerable uncertainties associated with a repository at an alternative location, including the time required to develop and implement a consent-based site selection process and achieve a willing and supportive host community.

The two alternative locations are in crystalline rock of the Canadian Shield in central to northern Ontario, and in a sedimentary rock formation in southern Ontario. Since the early 1970s the low- and intermediate-level radioactive waste produced as a result of the operation of OPG’s Darlington, Bruce and Pickering nuclear power stations has been stored centrally at the Bruce site. OPG said the existing storage practices are safe and could be continued for many decades. However, given that the waste remains radioactive for thousands of years, long-term management is needed.

Canada's Nuclear Waste Management Organization (NWMO) is in the process of selecting a site for a repository for used nuclear fuel, through a long-term programme called Adaptive Phased Management. Nine of an original 21 communities that expressed an interest in the NWMO repository are still involved in the process, but no site has yet been selected. OPG said the conclusions on cumulative effects presented in its environmental impact statement for the Bruce repository remained valid. The updated analysis showed no potential for likely adverse cumulative effects, and also showed cumulative effects as a result of malfunctions, accidents, and malevolent acts related to both repository projects would be unlikely, it added.

The Canadian Environmental Assessment Agency is now expected to review OPG's submission, including a public comment period, although the decision on the environmental assessment for the repository will ultimately be made at the ministerial level. The next step would be a decision on the approval of an application for a site preparation and construction licence.

Environmental groups have expressed concern that the planned Bruce repository could endanger Lake Huron, which is less than a kilometre away. The proposal calls for burying the waste some 2230 feet underground. It would be encased in a limestone formation that OPG says has been stable for 450 million years. The storage chamber would be much deeper than Lake Huron and the corporation says there is virtually no chance of radioactive pollution reaching the lake.