Both China and Russia have built operational SMRs. (Not to mention the fact that the nuclear reactors we’ve had for decades in military submarines and ship are SMRs). They exist.

We don’t have enough data about the economics or SMRs to say for sure, most (but not all) economic models put LCOE for SMRs at half the cost of traditional PWR nuclear reactors.

It’s hard to judge from the current smr projects what the costs will be. The largest cost in building nuclear power is all the regulatory oversight. Every PWR plant is different and needs to go through the entire process from scratch. But once we have some successful and proven SMR designs. They can be mass produced from the same vetted and approved designs without needing to go through the massively expensive design process again.

SMRs are simpler too. Which makes them cheaper. They don’t need as many layers of redundant safety systems like traditional reactors do. Even in the worst case scenario, an SMR can meltdown and a person living next door would be perfectly safe.

All of that adds up to the a lot of potential cost savings if we mass produce them.

If we can build enough solar or other renewable power to replace fossil fuels without nuclear, great.

But most people have no idea just how much it’s going to take. We need to not only replace all the fossil fuels on the grid today. Plus have extra capacity to charge storage for use when its night and cover the added demand of all the electric cars, trucks, furnaces, everything else that needs to become electric.

We need to be building nuclear too. We can’t build enough solar and wind fast enough.