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There are two ways of achieving economies of scale: making things bigger or making more of them.

For small quantities, the former is usually more effective -- making things bigger lets you make fewer of them, reducing costs.

For large quantities, a factory can enable insane economies of scale.

SMR proponents are talking about building dozens of reactors. That fits very firmly in the "small quantity" column where economies of scale almost always favor building things bigger.

by Arodex3 hours ago|

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If you need 500 MW, you build one 500 MW reactor, not five 100 MW reactors. They will take more space.

As for speed, a 100 MW reactor is not commissioned in 1/5 of the time a 500 MW reactor is.

by Jolter1 hours ago|

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I think the promise of SMR is that the 1/5th reactor can be built in 1/2 the time. And you build five of them in parallell. And you have your power sources gradually online over about the same time as one ”big bang” build would take.

I don’t think it’s going to work out that way, but that’s how it’s being sold.

by cauch38 minutes ago|

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Even like that, it is not clear-cut. 1/5 in 1/2 the time is still 2.5 shorter per worker, and building in parallel require multiplying expert builders, which is not easy (as it takes time to acquire the expertise and you don't want to learn a trade to build one project and have nothing to do next).

But, yes, I get it is how it is sold. Just that even sold like that, people with common sense should say "wait a minute, that's obviously not that simple".

by cauch3 hours ago|

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Just a guess (I'm not the previous user), but I guess you need to look at the space _per GWh_?

If a big nuclear reactor takes 10x more space but has 20x more capacity, then it means not having much space favors the big nuclear reactor rather than building 10 small ones that will take twice more space.

(and same for the time)

by john_strinlai3 hours ago|

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its probably my fault for not making myself clear. i mean when the available space is constrained to a specific amount of space that cannot be exceeded.

just picking random numbers:

i have 1 square mile available. a big reactor takes 4 square miles. i cannot fit a big reactor, despite the bigger reactor being more efficient.

by cauch43 minutes ago|

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well, I don't think that there is a real problem of "1 square mile is available but not 4 square miles" (this is a different sentence than "there is not enough space"). Especially as small reactor also need to be placed very specifically. So even then, it is still possible that the advantage is for big nuclear plant, as they are still more compact per GWh.

by john_strinlai34 minutes ago|

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>"1 square mile is available but not 4 square miles" (this is a different sentence than "there is not enough space").

how are these different? one is an example, one is general, but they communicate the exact same point. if you have something that requires 4 sq. miles, you cannot fit it into a place that is 1 sq. mile in size because there is not enough space to fit it.

>as they are still more compact per GWh.

i am really struggling here... if i cannot fit something large, whether the large thing is "more compact per GWh" does not matter. i only have so much physical space to work with. if its too big, its too big.

for a more easily visualized example, you cannot fit a reactor from three mile island into a submarine. efficiency doesnt come into the equation, because physical space constraints get in the way first.