Ontario Power Generation — which said it would pay for the reactors by relying on debt and funds raised from the utility rate instead of major government funding — is planning to build the first reactor at Darlington Nuclear Generating Station.
In total, OPG said it expects to spend $20.9 billion across the four small nuclear reactors. (Emphasis mine)

The first reactor, which is set to begin work this year, is priced at around $6.1 billion, while a further $1 billion is being spent on studies and other groundwork to get all four underway.

"This nation-building project being built right here in Ontario will be led by Canadian workers using Canadian steel, concrete and materials to help deliver the extraordinary amount of reliable and clean power we will need to deliver on our ambitious plan to protect Ontario and unleash our economy.”