In this particular case, what is this quote supposed to imply?
I don't know that it's supposed to imply anything but rather shine a light on the different acceptance criteria for a study reactor v. one that generates power for, in his case, mission critical needs (though power for homes and businesses would be life-critical, so it's up there).
If a study reactor breaks, even though there's a possible risk to life depending on how it fails, you can endure the downtime for a bit while bringing it back up. If a practical reactor breaks, people are far more likely to die.
Anything $M you have to fix in N of them costs Nx$M.
(1) It is simple -> nobody said NuScale's reactor is simple. It took NRC about 6 years to approve it, and in the process NuScale had to produce about half a million pages of documentation
(2) It is small -> not really. It is smaller than full size reactors, but then it delivers only 50 MW, not 1GW. Per unit of electricity delivered, it is most likely somewhat larger than a full size nuclear power plant
(3) It is cheap -> relative to what? it's not that cheap. If anything, see the comments in this thread, it appears to be expensive
(4) It is light -> this does not apply here. Rickover was concerned with submarines, where weight was important. This is not a reactor designed for submarines. I don't know how light it is, but nobody cares about this
(5) It can be built very quickly -> well, if the first one is supposed to get online in 2029, that does not seem to be very quick, does it?
(6) It is very flexible in purpose (’omnibus reactor’) -> NuScale's reactor is designed to generate electricity. That's it. What is flexibility in purpose?
(7) Very little development is required -> NuScale has already worked for one decade on this. It will take until the end of this decade to see one come online. Nobody claimed "very little development is required" It will use mostly off-the-shelf components -> not really. NuScale will use a Korean manufacturer that is accredited by NRC to manufacture componenets for nuclear reactors. There's nothing off-the-shelf about this.
(8) The reactor is in the study phase. It is not being built now. -> it depends what "being built now" means. NuScale can't start building before it has all the approvals. It is working on getting these approvals, if this counts as "being built now", then it's being built now.
More to the point. Rickover was talking about a completely different context. People venturing cheap ideas, while he needed concrete reactors for his submarines. We are in a different world. NRC is extraordinarily stringent. The fact that NuScale got their approval is a phenomenal achievement. This should not be dismissed with the same tired old quote from Rickover that gets posted on HN almost every time we talk about nuclear reactors.
Reactors can generate electricity, generate fission products (for biomedical uses, for physics uses, for weapons, etc), or both
Not really applicable here though
* Base-load vs turn on during peaks
* Simplicity vs shorter bring-up time
* Maximization of generation capacity vs efficiency, for a given volume of the plant
etc.
"In theory there is no difference between theory and practice, in practice there is."
It does reflect on me. It reflects the fact that I can't read minds.
You gave a widely known quote, and in your mind it was crystal clear what you meant. But to other people, who can't read your mind, it just sound flippant.
It sounds like you think NuScale is a bunch of theoreticians. And that with your remark you are trying to put down their decade-long quest to achieve something.
Maybe it does not sound flippant to you, but I assure you, it is flippant.
So by the time it is done it will be more expensive, likely heavier, likely way late, more complex and narrower in its possible range of applications. It's not a law, it is an observation made over many nuclear deployments and to the best of my knowledge there isn't a single project that was an exception so I expect it to be true this time around as well. Which is why you can safely ignore any of the touted advantages until the product is ready to be fielded in quantity. Assuming it ever will be fielded in quantity, plenty of designs were slated for large numbers of deployment and ended up being one-offs or at best single digit runs because of unforeseen issues with the design.
But although the most dangerous words in history are "this time is different", there are reasons to believe things could be different this time:
1. the Nuclear Regulatory Commission. NuScale got the design approval from them. That means this design is as good as frozen. The NRC is an extraordinarily conservative organization. If NuScale, or anyone who licenses their technology, will try to diverge from the approved design by a bit, ..., well that's not even a possibility, why should we think of consequences. So this design, by the time is in production, won't be heavier, more complex, or narrower in scope, because it will be this exact design. It may be more expensive, late, in fewer numbers than expected, however.
2. Conservativeness of the design. This reactor is just a pressurized water reactor design. The most widely used today. It's in a small form factor and modular, but otherwise there's nothing revolutionary or radical about it.
3. History. After about 70 years of reactor operation, the NRC has seen lots and lots of failure modes. The number of new failure modes to be discovered is not zero for sure, but it asymptotically approaches zero. The reason for a lot of past construction delays was the moving of the goalposts by the NRC, but that was due to the discovery of new failure modes, not to any malicious intent. The goalposts may still move between now and 2029, but much less.
4. Politics. In the past few decades, at least in the US, the left was against nuclear power, and the right was for it. Now it appears a large number on the left have embraced nuclear power, so some form of bipartisanship has been achieved. This is quite unprecedented. Will it last? Probably not forever, but it might last a few election cycles, and this could be enough for this SMR design to achieve some escape velocity.
And as you tacitly admit modular is revolutionary and there are a whole pile of challenges right there, having a single (large) point of failure may well be much easier to manage than several smaller ones, I never saw the modularity as the problem to solve, because existing (large) reactors are more often than not also created in sets to deal with downtime due to maintenance and overhauls.
Your third point is accurate, but also may end up being this projects downfall: by changing some core design parameters (such as size) new failure modes may well pop up. MTBF is mostly a function of the number of components, if you increase the number of components, even if the components are smaller you will probably still see more failures.
Four is true, but: here in NL we currently have the same situation and a new reactor was just greenlit (two, actually if I understood all of the material right). But this is a decade+ project and I suspect that given the fickle nature of these projects that there is a fair chance that it will eventually never see the light of day because of the dark horse of economics: a typical nuclear plant will generate power, but it will never generate any money. Without subsidies these are essentially dead ends.
A (previous generation) terrestrial plant already has systems that can dump ludicrous amounts of water onto the core, but they all rely on there being power to operate pumps. A nuclear submarine that can dump in sea water does not need this - the body of water it is in is cold enough (relative to the heat in the core) that it will naturally carry heat away.
I'm not sure there we currently have the supply chain, security and ability to deal with geopolitical fallout of using the same fuel for mass domestic use.
The French K15 reactor runs on 7% enriched fuel.