The key point with small modular reactors vs. reactors like this is that construction happens in factories rather than on site. Theoretically, you might get some economies of scale from series production in a factory that is much harder to get doing bespoke construction projects. Which is why historically, nuclear projects tend to blow through their cost estimates and why having larger reactors makes that a bit more tolerable. Of course until somebody actually does this and scales to hundreds/thousands of reactors production, this is all theoretical.

This particular reactor is already estimated at over 5 billion $ I think. That's a lot of money for just 300MW and it probably could end up being a wildly optimistic estimate as well. I think effectively much of the construction is still on site and not in a factory. Hence the need for a construction permit. So, you get all of the downsides of complex on site construction such as including high cost, permitting overhead, lots of bureaucracy, associated delays & uncertainty, etc. without the upside of actually delivering a lot of power like you would with a larger reaction. Calling it "modular" might be overstating things a bit.

Probably cheaper, faster, and easier to just plonk down 5GW of solar, wind, or battery (or combinations of those). Especially if you calculate in the 200-300% time and dollar budget that many nuclear projects seem to end up having. Maybe this one will be different. A lot of people have a lot riding on Nuclear projects breaking this trend. But then that has been the case for decades.

> A large reactor may have a better cost per kWh, averaged over decades of its lifetime, but a smaller reactor likely has a more affordable upfront cost.

What are the civil works costs for a small(er) reactor versus a large(r) reactor?

The label SMR applies to a wide range of reactors.

The BWRX-300 is at the upper end of that range and I don't think claims of factory-production of the whole unit were ever made for this reactor.

That said, even the much larger AP-1000 had fairly large modules made in a factory. In fact as far as I understand that was one of the problems with the Vogtle builds, because doing that only really makes sense for a larger number of units, not for just two unites.

Going by the last table at

https://www.icetransport.com/blog/what-are-the-maximum-overs...

("Oversize/Overweight Permit Limits by State (Standard Freight Loads") that should be deliverable by truck with a permit.

I think that when people casually pronounce a bet like that, they generally mean even odds. If they meant something else they'd likely say so explicitly.

Sadly, the ABWR has also proven to be unreliable and uneconomic.

Hitachi spent most of the 2010s trying to get a couple of them underway in the UK (which has a generally favourable regulatory environment) but eventually pulled out after 12 years with £2bn spent and nothing built.

Maybe the BWRX will have better luck - but I'd not want to stake any money on it myself.

Smaller reactors = more reactors.

More reactors = riding the cost curve more quickly.

Nuclear reactors are highly profitable:

https://www.youtube.com/watch?v=cbeJIwF1pVY

Lowest LCOE by far is "nuclear LTO (Long Term Operation)".

https://www.iea.org/reports/projected-costs-of-generating-el...

Yes, the plants are big and expensive, but once built, they are cheap to run and last pretty much forever.

SMRs lower the up-front cost, the time to build, the risk, and the financing costs, which are the biggest component of the construction costs.

Initially at somewhat higher cost per kWh, but there is plenty of headroom there. And the various nuclear startups have cost projections that range from 2-3 cents to below 1 cent / kWh.