While we shouldn't be shutting down existing nuclear, unless there are special circumstances it's a bad idea to be building more.

Don't get me wrong, I'd rather see new nuclear than new gas, and obviously no new coal should be built anywhere under any circumstances, it doesn't make any sense to add nuclear when solar or wind plus storage is cheaper - and it is.

The report sounds suspiciously like an industry hit piece TBH. The arguments given, while possibly true, have been touted around by opposition groups to all of the other options being developed:

- wind (too expensive, only generates when the wind blows, too far away from users to be useful, ugly),

- solar (too expensive, only generates when there is sun, ugly),

- large-scale nuclear (unbelievably expensive, ugly, still we don't really know what to do with the waste),

- coal/gas (now expensive, bad for the environment, will run out at some point so we need alternatives anyway).

And now we have SMRs: expensive, still generates waste that we don't really know what to do with.

You need to pick your poison(s). They all have problems. New tech is always expensive to develop otherwise we would have been doing it years ago.

What we probably need is a comprehensive mix so that issues with supply don't cause us major problems. So we don't really need people saying that one technology is taking too much of the limelight. Limelight isn't a limited commodity, and we certainly would not benefit from putting all our eggs in one basket yet again.

It was fashionable to tout "too expensive" against wind and solar for a while, but awkward reality has mostly put the kibosh on those, since they both turn out to be *ridiculously* cheap.

Now the somewhat-sensible con is intermittency (which is why sensible folks are putting a lot of effort into storage tech) and the Ludicrous Orange Guy con (for wind) is "won't somebody, please, think about the birds?"

Another area where they're not so rosy is in carbon emissions. They're better than fossil fuels but the spreading out of generation means that they're more carbon-intensive than nuclear, thanks to everything from the concrete (especially for those giant offshore ones) to the increased number of substations (made drastically worse by SF6). Hydroelectric can compete but only under specific circumstances, namely, where you're not flooding fertile land and belching methane into the air.

While there is some truth in that, reactors a qualitatively different. SMRs have only one thing going for them: The unproven theory that they could be made much cheaper.

- When anything else proves uneconomic, it can be abandoned. You have to avoid the disintegrating old wind farms, but they can be ignored. When a reactor becomes uneconomic, it can't be ignored, and the taxpayer will have to pay to deal with it after a few decades as eventually corrosion will make it .

- The end-of-life radioactive waste vs MW ratio is very likely to be far worse than large reactors because of the usual volumetric scaling effect.

- A small nuclear installation has 100% of the siting and permitting costs and problems of a big reactor. i.e. the per MW costs are much higher. Lots of small industrial sites seem like a fantasy.

- "Problems" probably scale with the number of units more than the size of the unit. Lots of SMR's are probably more problems than the same MW of big reactors

- A small reactor just doesn't produce that many dollars. It's not clear that anyone would ever want the grief of siting a reactor for the amount of value it produces.

- I don't think any private company has every decommissioned a reactor at it's own cost. Ever. As soon as the number of old SMRs becomes a flood, the manufacturers will just demand the state pays them to clean up the mess. In the absence of a massive prepayment escrow system, which would be such a rich target it would be raided, there won't be money to clean them up.

The reality is that the nuclear industry left it's run at an acceptable modern reactor 20 years too late. There are some promising ideas underway like Moltex which looks like it could be an economic upgrade on existing nuclear sites, but they are probably still 20 years away from being rolled out at scale. It simply began too late.

"still we don't really know what to do with the waste"

We used to do something with the waste but thanks to Jimmy Carter it was made near enough impossible so the switch was made to a once through and very expensive fuel cycle. When you are throwing away 95% of your usable fuel then nuclear looks like a very bad option... and that was the point.

I personally don't like SMRs as it is perpetuating a very old and not very good design of reactor. If we'd spent the last 40 years looking at GEN4 reactors and beyond rather than dragging our heels and listening to the doom mongers we'd be in a much happier place AND we'd have something to do with the current 'waste' stockpiles.

Why the obsession with tiny reactors everywhere? You're just increasing the sets of risk and upside/downside on novel reactor ideas with new fuel formats. Just asking for problems, costly problems.

Meanwhile no one is bothering to follow through on latest generation reactors with passive safety features. Strange that.

The politics around nuclear energy are a disaster. (Take Lake Anna for example, a nuclear cooling lagoon where the locals stopped construction of another reactor because after all, they're entitled to cooling lagoon-front property and a third reactor may endanger that)

(Specifically the Economic simplified reactor by GEH)

On the contrary the UK knows a great deal about small, very reliable nuclear reactors. We use them on submarines and have done for decades.

Limited numbers, low power output, and even less planning than usual about how to decommission them.

I'm a big fan of nuclear power, but I'm not going to cite those reactors as role models.

And the price per MWh ever generated is truly eye watering.

I was a bit surprised the Russian nuke barge was so slow and problematic.

If submarine reactor are so easy, why** do we not have nuke barges already? Britain, France, US, Russia (not to mention Australia), all have the reactors as well established, proven designs.

(**They use high enrichment fuel for starters.)

Technically we could reuse spent fuel, (MOX) build incredibly safe and effective reactors, store waste securely and safely.

Politically? No. (Technically we could be colonizing the stars, its the political garbage what makes everything a nightmare mess)

"Technically we could be colonizing the stars"

Could you fill in the detail a little, please. I'm sure a lot of us would like to know about this startling news.

The local right wing government in my province has embraced SMRs as an alternative to doing anything to reduce reliance on gas / coal. Toss in some token research dollars and sign onto a coalition, and they get to kick the can down the road 15-20 years when it will be someone else's problem. The magical promises of SMRs has surprisingly broad support across the political spectrum.

One of the several objections to fission power is that it's a very poor use of capital. Glad to see some authoritative backing.

This kind of article irritates energy engineers. Thinking that nuclear is just a 'stop-gap until renewables fully mature and see widespread adoption' is a fantasy rooted in ignorance. There is no single correct technology family that we just need to back exclusively. We will need to do lots of everything. Energy is a whole-system problem, involving the availability and use of land, raw materials etc, as well as the issue of intermittency.

For example:

https://www.oecd.org/publications/the-costs-of-decarbonisation-9789264312180-en.htm

Renewables are fine up to a point (having used a lot of copper, rare earths etc to build) but become an expensive problem to fully rely on. Therefore, nuclear, while having costs and downsides, fills that piece of the puzzle. Already the price of electricity goes negative on the European grid when there is too much sun or wind (storage at serious scale and duration is hard and far off). Therefore the LCOE of the generating plant is irrelevant, since the *value* of the product is almost nil during these periods.

This is also just taking about electricity - there is the rest of the energy sector to decarbonise too, and it's a lot bigger...

Hi -- we've reviewed the piece and, yes, stop gap wasn't the right word for the reasons you've given.

For one thing, as a publication, our editorial line is that nuclear is not a stop gap - we should be in it for the long haul, and the nuclear by its very nature is a long-haul undertaking. There's no stop gap to it.

We've tweaked the piece accordingly. Thanks for the feedback.

C.

I've always wondered about the viability of the concept. Nuclear reactors require that the loss of neutrons be kept small enough to allow a nuclear chain reaction to be maintained. That is hard to do with a small reactor unless you use highly enriched fuel. That in turn raises questions about economics and possibly nuclear proliferation.

...but if their data points are designs primarily in Russia and China that were apparently initiated some 15 years ago, this research is not analysing current western technology.

Further, some corners of the renewable industry has been doing all it can to mobilise against Nuclear (see the recent controversies in Germany, which are in some cases quite shocking), whilst carefully ignoring the issues with intermittency and reliability that remain unsolved problems that seriously limit the capabilities of wind and solar. Demands that all investment is only in renewables has choked development of Nuclear - so pointing out that no serious developments have been made in the west is probably more a symptom of a distorted market than an indication that the technology is not capable. This should be a sign of a problem to be solved, not a case for dismissal. Unfortunately admitting as such risks loosing critical subsidies... and we get reports like this.

Not that renewables don't have an important place in a multi-modal energy grid, but *some* of the recent development work has only been made possible by artificially supressing work on serious alternatives. The risk here is that we end up with an energy grid that is unreliable, intermittently expensive and unable to support long term investment. Few people fully understand that the current occasions of negative energy prices are a warning sign not an outcome to be celebrated.

That was exactly what I was thinking too - evaluating 4 devices that are based on technology that's over 10 years old is ridiculous. At the time those projects were starting, the only extant technology was naval propulsion systems. Previous commentors have correctly spotted the weaknesses of adapting those technologies for civilian power production. It's far too soon in the life cycle of SMRs to do this kind of "hit job" based such a small number of devices. At this point there's no way to evaluate the possible scaling factors that might be evolved.

Also, I would not grant any credibility for results from any of the 3 countries mentioned.

One of the original attractions of SMR was the short build time. Why has it turned out they take so long to build?