While reactor vessels themselves are most expensive single piece in the nuclear power station, they are not going to save much on them by making them smaller, and they would not get any cheaper from mass manufacturing.
If you said something like "mass manufacturing wont make them cheap enough to be economical", that seems believable, but I'm not sure how you can blanket declare it wont make them any cheaper.
The "something" to be manufactured isn't nuclear power plants.
If we made a few 5 MW plants at a certain price but then decided to scale that up and produce huge amounts of 5 MW plants then we could obviously produce those plants at a significantly lower per-unit cost. Everyone agrees. But our goal with electricity isn't to make plants, it's to make watt-hours of electricity.
So what is cheaper? Manufacturing, setting up, operating, and securing 1000 5 MW plants or one 5 GW plant? It seems like the 5 GW one might be cheaper.
Wrong, actually. Whenever multiple nuclear plants for submarines in a given class are manufactured, the fact that multiples are being built does lower the cost, although most of that is just from having a complete design to use rather than any kind of mass production. Navy reactors aren't really SMRs since they're also old technology, but they're a good example of how much easier/cheaper/greener it is to build small reactors instead of large ones.
> It seems like the 5 GW one might be cheaper.
Small modular reactors typically run up to 300MW in size. There are very few applications for a 5GW reactor. Besides, the costs of the small reactors in terms of time, money, operating expense, security and other things are so much less than for the large plants that the math really doesn't work anyway, even for your extreme example of 1000 5MW reactors.
It's not 1000 5MW plants vs 1 5GW plant, each SMR plant would have dozens of smaller cores. Most of the plans I see are in the 300MW - 1100MW range.
> Everyone agrees. But our goal with electricity isn't to make plants, it's to make watt-hours of electricity.
If the goal is to create carbon free electricity then making as many carbon free power plants is exactly how you'd get more watt-hours.
But for me the biggest issue is, if fighting climate change is so important, why wouldn't we try everything possible? Why do so many people insist on only renewables?