design energy

The age of small modular nuclear?

There was something of a non-sequitur from Britain’s Chancellor Jeremy Hunt recently. “We don’t want to see high bills like this again,” he said of the country’s current energy costs. “It’s time for a clean energy reset. That is why we are fully committing to nuclear power in the UK, backing a new generation of small modular reactors.”

If I was hoping to bring down energy bills, then nuclear isn’t the first place I’d look. The cost of Hinkley Point C, Britain’s first new nuclear power plant in decades, was originally priced at £16 billion. That made it the most expensive building in the world, and that was before costs began to spiral upwards. The latest estimate is that it will cost £32 billion. So it really doesn’t make much sense for Jeremy Hunt to be promising lower bills with nuclear power.

But maybe it’s not about megaprojects like Hinkley. Maybe, as Hunt suggests, the future lies in the much vaunted Small Modular Reactors (SMRs). A number of agencies are looking to smaller reactors that can be standardised and therefore built quickly and cheaply – cheap being relative in the world of nuclear. It ought to be cheaper to install a chain of SMRs than to build one massive and bespoke power station.

The theory is that if they are small and they are modular, then SMRs would be closer to a manufactured product than a construction project. That would mean economies of scale, and potentially prompt the kind of decline in costs that we’ve seen in solar or in battery technologies.

But SMRs have been discussed for years. How close are we to seeing them as part of a low-carbon electricity grid?

Let’s start with who is working on the idea. A recent overview of the sector from the OECD includes this map of various projects. It’s not exhaustive, but it shows the major players.

Most of the action is in the US, with other projects in China, Britain, France, Russia and a handful of others. Some of these are private enterprises, particularly the American ones. Elsewhere a lot of the work is coming from state-owned nuclear companies such as EDF in France, or Argentina’s CNEA. Anyone who has invested in nuclear power and research in the past is likely to have an SMR project on a drawing board somewhere.

Is anyone actually building them? Sort of, but only China and Russia have working SMRs so far – a demonstration plant in China, and Russia’s pioneering floating nuclear power station, the Akademik Lomonosov. I wouldn’t consider either of those to be good examples of what SMRs are supposed to be, but they’re the ones that get mentioned. Construction on further plants is underway in both countries, along with Argentina. As the OECD notes, “there are currently no SMRs licensed to operate outside of China or Russia.” Everywhere else, SMRs are in various phases of research, design and planning.

This doesn’t tell us much about how long it’s going to take to bring SMRs into the energy mix. That’s because the big obstacle in nuclear power isn’t technology, but regulation. It’s incredibly difficult and slow to bring a new nuclear technology to market, and rightly so, given its dangers. Licensing a new nuclear design in the US takes five years and costs a billion dollars – and that’s before you even apply to build anything. That’s just to confirm that the design is safe.

Things move incredibly slowly in the nuclear world. The concepts for the European Pressurised Reactor that’s being built at Hinkley Point – and which is considered a new design, were being done in the mid-nineties. So of the long list of companies with concepts for SMRs, how many of those will ever get built, and in how many decades? From a climate change perspective, speed matters. We don’t want to accelerate nuclear power at the expense of safety, but at the moment it is going to take too long to bring any of these new reactors online.

Here in the UK, there is one firm that is synonymous with SMRs, and that’s Rolls Royce. Any article on the subject in the UK will mention Rolls Royce, and often illustrate the article with a glossy picture of their proposed design – as I’ve done above. What’s odd about this is that Rolls Royce’s design isn’t a small modular reactor. It’s being called that because it’s a buzzword, but it’s 470Mw in capacity. That’s smaller than Hinkley Point C at 3,300Mw, but it’s a whole lot larger than what is generally called an SMR.

Neither does it use modular reactors to achieve its larger power output. What Rolls Royce are doing is using modular construction techniques to build a traditional reactor a bit quicker. On Michael Liebriech’s Cleaning Up podcast, the CEO of Rolls Royce described it as “a Lego kit of parts” for building a nuclear reactor. So it’s not actually an SMR, but why not call it one if you can tap government funding by pretending it is?

Looking at where we are at the moment, I expect there will be a new generation of smaller nuclear power stations at some point in the future. I expect China will do it first, and that the economies of scale will happen there. If it ever reaches the UK, it will be a few years away.

A more urgent question is whether or not a new generation of nuclear power will happen in time to make a difference to climate change. That looks far less certain.


  1. I’ve always felt that anything nuclear is an appalling accident waiting to happen ( even decommissioned and under ground).
    Am I right to fear them?

    1. Yes, and it’s important to note that there are different kinds of nuclear power plants. The earlier ones could go disastrously wrong if they were mismanaged. More modern reactors are designed to be ‘walkaway safe’ – they just shut down by themselves if there’s a problem. We are a long way from the early days, and a lot has been learned.

      1. ” More modern reactors are designed to be ‘walkaway safe’ – they just shut down by themselves if there’s a problem. ”

        None exists.
        You are talking about fantasies.

        1. ‘Walkaway safe’ refers to the fact that in the early days of nuclear power, reactors would go into meltdown if they got out of control. There have been many iterations of nuclear reactors since the first generation, each improving on the safety aspects.

          To take a real world example, the reactors at Fukushima automatically shut down when they detected the earthquake – something early reactors couldn’t do. Where they failed is that they still needed diesel pumps to run cooling systems to vent heat out of the reactors, and these were hit by the tsunami. Small modular reactors do both – they shut down, and they don’t need additional cooling systems. So they are safer.

          Safe is relative of course, and the term ‘walkaway safe’ promises more than it can deliver. There is no such thing as ‘safe’ nuclear power – how could there be when dealing with radioactive materials? On that we agree. The question I’m interested in is whether it’s better than the alternatives. And coal power is utterly disastrous, for miners, for those breathing polluted air, and for the climate.

          I don’t like nuclear power, by the way. I’d very much like to do without it, and I’m an advocate for renewable energy, storage and a major focus on efficiency and demand management. But I’m not convinced we can do without nuclear power either.

      1. Good question. I believe it to be safe because of statements made by a friend who is a nuclear engineer working in the nuclear industry in the U.S. She (and others) have said that nuclear power is so well done now that many are not even aware when a nuclear plant provides them with energy. The big accidents (Fukushima, Tchernobyl) are what gets our attention, and they are spectacular and scary, but extremely rare.

    2. ” The majority of France’s power … ” is now imported or generated using non-atomic sources resp. we are seeing this coming. So does the French ‘ La Cour des Comtes’, the financial overseeing authority:

      Machine translation:

      I think you are mixing up “production” with “consumption”?
      France is since last year a net importer of electricity depending mainly on Germany/Belgium /Spain(atomic exit nations) and the UK.

      1. The link to the last report of the Cour des Comptes:

        Machine translation:

        The French government has given up ALL climate catastrophe targets and is preparing for 4 Kelvin temperature increase resulting in 40% less precipitation by 2100 (meaning no more cooling water for the reactors and no more hydropower):

        Machine translation:

        The war for water started some 5 years ago in the South-West when a protestor was shot dead by the police with a grenade in his back, now it is the new normality to shoot at people fighting for water:


        1. Yes, a protester was critically injured and as many as 26 police ended up in the hospital. Had not heard about this incident at all. The mainstream American media should cover climate change much more aggressively. Am grateful for The Earthbound Report’s excellent angle. It’s terribly sad and depressing that deadly conflicts over water have begun between farmers and environmentalists in France. Thanks for the links.

      2. First, thank you for bringing up this interesting debate. A few things. 1) I used “believe” as a synonym for “think.” We are not engaging in any religious debate, but I want to admit that my knowledge of these industries is mostly second hand, coming from sources I trust, but not based on in-depth research I can personally assure, as I’m not trained in physics. 2) I appreciate the passion you bring to this issue. I speak and read French, so I read that same article and came up with a different translation myself. In 2019, according to the IAEA, 71% of France’s power came from the nuclear sector. That is the highest percentage in Europe and it has not dropped much since 2019. The article you shared correctly points out that France’s nuclear power plants are aging. They will have to address this if they intend to continue generating energy from nuclear power. I appreciate the passion you bring to this issue and am sorry not to be able to continue debating this as I’m not capable of debating nuclear pro’s and con’s. I simply wanted to make a point that not everyone finds it to be an entirely negative thing. It has problems, but so do all energy sources, including the clean, renewable, non-nuclear ones. I hope you find a platform where you can debate this more vigorously, and thank you for bringing up some interesting points.

          1. Thanks. Yes, it looks as though French nuclear production sank to a record low in 2022 because some of the plants needed to be closed for repair. Thank you for offering to send links, but I’ll find them if I need to, am sure. Thanks again for the insights!

            1. re. ” … French nuclear production sank to a record low in 2022 … ”

              Nearly every year shows a new record low in output.
              No other nation is quitting atom power as fast as France (in terms of reduced output):



              Not only because of repairs but also due to failed engineering (Astrid,EPR … ) and also due to collapse of reactors called ‘retiring’ (Fessenheim).

              I think French peak atom power production was in in the 90s?


              France en detail:


              It does not look as if there will be an uptake in 2023:


              Quarterly Futures at the EEX are rocketing for the coming winter,again.

              Europe’s energy crisis was caused by the failing French reactors due to mechanical faults and not because of human error or the gas boycott of Russia as some ill informed commenters have stated:


              Heavy industry in France closed en masse this winter, schools closed because they couldn’t afford to keep machines and people warm enough to function ( links on demand).
              Without these closures (pinked-up: ‘energy saving measures’) the share of atom power in total power consumption would have been officially under 50% since November 2022. For the mainland.
              Including all islands and colonies the atom power share in France is probably <50% since 2021 ….. .

        1. Here we go:
          “Avec 279 TWh produits (soit 63% de la production totale en France) … ”

          63% of atom power share in the production.


          You are indeed mixing up ‘production’ with ‘consumption’. France was a net importer of electric energy in 2022, see the link from RTE.
          From the ‘production’ a few percentage points have to be deducted for transmission losses and on spot consumption by the generator itself before we get to ‘consumption’ of the final consumer.
          The higher the output of a centralised generator the larger the loss.Ball park figure for atom power plants is 5% plus.

    1. @Juri Hertel – your link goes to ‘page not found’. Can you search for it again please, I’d like to have read it.

      1. Hi, here again:

        ( in the first link the last 3 numbers were missing, my excuses)

        If the link is still not directing use the head line of the article in the each engine:

        “NuScale Power, the canary in the small modular reactor market”

        The company has lost over 40% of it’s value, burned money and produced nothing but emissions.

        Since economical facts are very short here in the ‘discussion’ (any numbers as such) I link again to the Russian disaster using first hand experience with the Akademic Lomonosov:

        Machine translation:

        Other grid connected mini reactors do not exist.Despite being available from the shelf since more than 50 years.

        1. Yes, at the moment there’s a lot of buzz about small modular reactors, and lots of start-ups hyping their particular designs. I would expect most of them to fail. As I said in the article, it is big nationalised nuclear authoritities that are driving this forwards, using the deep pockets of the state.

          1. Indeed,atom bomb states have no moral problem to drain the blood from the people before burning them.
            Capitalism commercialises everything.
            Even it’s own end.

  2. Re . China
    The author writes that he believes in China building mini atom power plants but states no sources to this economic madness.
    Chinese shipyards are getting orders from Russia for a second Akademic Lomonosov it seems but not for the reactors themself.

    A correction to the map the author has presented:
    Urenco (owned by Germany,Netherlands,UK) has left the mini atom power plant circus:

      1. Thanks for the back-up.It seems to be an experimental reactor,no need to have it built in the vicinity of several other reactors which by far outsize it,certainly not “commercial”.
        See the electricity costs of the Akademic Lomonosov linked further above.

        Here a bit more on the demonstration project:

        Some errors (200 Watt households?) in the article but here is more:

        Thanks again.

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