TORONTO -- This material first appeared in The Climate Barometer, our weekly email newsletter covering climate and environmental issues.

Four provinces are pondering the nuclear option.

Nuclear power is already a major part of Canada's energy arsenal. According to Natural Resources Canada, nuclear is the source of approximately 15 per cent of Canada's electricity. There are 19 nuclear reactors in operation at six power plants, all but one of which are located in Ontario.

Now, Alberta has joined Saskatchewan, Ontario and New Brunswick -- yes, the same quartet that most strongly opposed the federal carbon tax -- in studying small modular nuclear reactors, or SMRs.

Heralded by their proponents as a powerful, cheap and adaptable form of clean energy, these reactors are much simpler to set up than traditional power plants -- making them potentially advantageous for settings such as remote communities and temporary work sites.

They received their first approvals in the United States last fall, and the four provinces announced last month that they want to move forward with them here. An initial project, built at a nuclear site in Ontario, could be live by 2026.

But while the premiers of those four provinces sound optimistic about the future of SMRs in Canada, and business leaders seem equally convinced that these reactors can truly be a sustainable part of Canada's energy future, they'll face significant opposition in getting any sort of wider adoption off the ground.

Dozens of environmental and public advocacy groups signed a letter denouncing SMRs last year, arguing that they are more expensive to build than wind or solar power sources, create fewer jobs, and do less to address the climate crisis.

Another major issue with nuclear power, at any scale, is what happens to the surrounding area if something goes wrong. Think of Japan, where in 2011 a tsunami and earthquake prompted a major accident at the Fukushima nuclear plant. Anyone living within 20 kilometres of the plant was ordered out of their home, and adverse health effects have been reported in nearby wildlife.

That disaster was back in the news recently, when the Japanese government announced that it will start sending contaminated water from Fukushima to the sea in 2023, in the process downplaying the concerns of environmental groups and fishery operators, among others.

Theoretically, something like this can happen in any country that produces nuclear power. But there's a much more tangible concern that affects all nuclear nations: its waste.

Unlike hydroelectric or coal power, nuclear energy does not produce greenhouse gas emissions. It does, however, create radioactive waste that can remain toxic for thousands of years.

Government regulations require this waste to be stored in ways that minimize the risk it could ever pose to the health of Canadians or the environment. It is kept in a pool for up to a decade, then transferred to dry containers and buried deep underground.

Understandably, though, nuclear waste isn't exactly something many Canadians want near their homes or their drinking water.

And that brings us to South Bruce, a rural community bordering Lake Huron in western Ontario. It's located two municipalities over from the Bruce Nuclear Power Plant, which is the largest nuclear facility in Canada and was once the biggest in the world.

In other words, Bruce Nuclear generates a lot of nuclear waste -- and it all has to go somewhere. That's where South Bruce comes in. Nuclear waste officials say they've narrowed their search for a new depository down to two locations: there, or a 1,700-kilometre drive northwest in Ignace, Ont. No decision is expected until 2023, but exploratory work is underway.

In South Bruce, there is both support for and opposition to the idea. Proponents note that the project would bring thousands of jobs to the municipality, which is three-quarters the size of Toronto but has a population of less than 6,000. Opponents are concerned about even the remote possibility of a leak, especially given the proximity of Lake Huron, and the possibility that opening their land to Bruce Nuclear's waste might encourage other nuclear plants to try their luck in South Bruce as well.

If this all sounds a little bit familiar, it may be because you're thinking of a completely separate 15-year battle over a nuclear waste depository even closer to the Bruce Nuclear plant. That plan, which was vociferously opposed by Indigenous groups, environmentalists and literally hundreds of communities in Canada and the U.S., was pulled off the table last year.

However, there is no direct connection between that plan failing and this one popping up. The previous proposal came from Ontario Power Generation (OPG), and involved low- and intermediate-level radioactive waste. South Bruce and Ignace, on the other hand, are in the running for a federal facility to hold waste with a higher level of radioactivity.

Some of those opposed to OPG's plan have also come out against the idea of building the federal facility in South Bruce, suggesting officials may also have a hard time selling the public on this proposal.

Whatever happens, though, all sides can agree on a few things: Canada will keep producing nuclear waste, it will remain highly toxic, and it will have to go somewhere.