[bryanlarsen]

SMR's make absolutely no sense to me.

Any engineer knows that one-offs are way easier & cheaper to design & build than production-ready designs & the factory to build them. Building a prototype car is an undergrad project. Taking it to production costs billions. You need significant volume before factories make sense, and it's not clear that SMR's will cross that threshold.

But let's say that SMR's do cross that threshold. Then what? A power plant incorporating one or more SMR's is still a mega-project with all the problems that mega-projects and especially nuclear mega-projects have. You still have all the planning & permitting costs, the large building with special design needs, the cooling infrastructure, the massive expensive turbines, et cetera. SMR's only target a very small fraction of the cost of a nuclear project. Halving 10% of the cost is not going to make nuclear competitive in a world where it has to compete with other power sources being at least an order of magnitude cheaper.

Coal plants and fission plants have a similar principle: they heat water to turn turbines. So you're highly unlikely to get their cost below that of a coal plant. A new build 600MW coal plant was estimated to cost $2B in 2008.[1]

1: https://schlissel-technical.com/docs/reports_35.pdf

[LargoLasskhyfv]

Maybe it's about the ability to build the reactor vessel itself smaller, more like 'common of the shelf', utilizing shipyards, or their supply chains.

I think I've read something about that being a choke point in the way of envisioned mass production.

The capacity to build large reactor vessels en masse isn't there, and probably won't be, for economic reasons.

[Arnt]

All this makes sense, but Rolls Royce surely has heard all of it and yet decided to invest. I do wonder what arguments made RR decide to invest.

[bryanlarsen]

It doesn't need to make sense, you just need to have a market to sell it into. And that market is massive, it's basically any government worldwide that has bought the rhetoric that renewables don't work. Ontario, Saskatchewan and Poland are 3 examples off the top of my head, there are many others.