5 ms·

>scale This is so funny to see, and great to see said, because for decades I ran into nuclear proponents (not engineers or workers, just people into the politi

>scale This is so funny to see, and great to see said, because for decades I ran into nuclear proponents (not engineers or workers, just people into the politics) that said that nuclear was the "only" way to combat climate change (Edit: forgot a crucial clause: because "only" nuclear could scale). I would counter that nuclear does not scale in that it can't get small, and it takes forever to build or expand. Whereas solar can go small, go big, go medium, and the same with storage these days. Many in the nuclear world are currently hoping to scale to "modular" size, because it's become clear that with 1GW scale, in advanced economies, construction is too expensive (IMHO due to the high cost of labor compared to less advanced economies). So shifting to a more "factory" model like airplanes is the investment pitch: scale smaller and make each reactor like factory parts so that it gets cheap to build. We will see! It's got enough hype that even non-small non-modular designs are calling themselves SMRs in order to try to garner interest. And there is some interest in new nuclear these days, despite the extremely high cost, and its going towards the more expensive SMRs rather than 1GW scale reactors, because the risk of failure is on a smaller overall quantity of money.

JumpCrisscross 2y ago
> nuclear proponents (not engineers or workers, just people into the politics) that said that nuclear was the "only" way to combat climate change You’re seeing the same nonsense with armchair solar + battery advocates today. The mistake is in assuming marginal advantages persist across scale, i.e. in ignoring the law of diminishing returns. If we could have deployed nuclear immediately and infinitely when those folks were talking, they would have been right. We could t. If we could solar and batteries immediately and infinitely (without increasing prices), going all in on it would be right. We can’t. Most markets optimise heterogenously because that’s what makes sense.
- epistasis 2y ago
  > If we could have deployed nuclear immediately and infinitely when those folks were talking, they would have been right. We could t. If we are talking about the US, the reason we couldn't deploy nuclear was that we vastly over-ordered the amount of reactors we needed, going into the 1980s, causing a glut then a drought. And then too many of them were financially disastrous construction projects. Some people say that we had too many different reactor designs, but I would point to France where they used the same reactor design but also did not see falling prices, and did not build nearly as many reactors as they had planned. Certainly France has been much better off in terms of carbon emissions from electricity since the 1980s than most places in the world, but they were also going nuclear due to lack of cheap fossil fuels. > If we could solar and batteries immediately and infinitely (without increasing prices), going all in on it would be right. We can’t. If I'm understanding you correctly, you're saying we aren't going all in on solar and storage, but I would argue that we are. Nearly all new generation capacity getting installed is solar, storage, and wind. THere's a few legacy projects for other technologies, but those natural gas plants will see little use, unless solar/storage/batteries are blocked from being deployed in the same area. EIA: https://www.eia.gov/todayinenergy/detail.php?id=62864 https://www.eia.gov/todayinenergy/detail.php?id=62864 This is happening in China too. They build coal plants, but they barely use them as they are just backups. Last I heard they are on track for 160GW of solar deployed this year alone, and it goes up every year. So maybe put me into the bucket of people spouting nonsense about solar + batteries today, I could be wrong, but I really think it's the only tech stack that can and will make a big change in energy over the next 10 years.
  - robertlagrant 2y ago
    > Certainly France has been much better off in terms of carbon emissions from electricity since the 1980s than most places in the world, but they were also going nuclear due to lack of cheap fossil fuels. That's the point: 2024's solar is better than 1980's nuclear, but in the meantime we've pumped a lot of CO2 into the atmosphere we didn't have to.
    - pfdietz 2y ago
      It's difficult to see the relevance of your point. Are you saying we should build nuclear now because we didn't then? That would make no sense. This isn't some sort of arena where we have to be fair to inanimate objects.
      - JumpCrisscross 2y ago
        > difficult to see the relevance of your point. Are you saying we should build nuclear now because we didn't then The same statement will be true in twenty years. We’re not building gas generators because they’re pretty. We have power demand growth well ahead of our solar and wind deployment potential, even assuming the rosiest production growth forecasts for the next ten years. That gap is being filled with natural gas, based on infrastructure with 20 to 40-year financing timelines. Not building a nuclear plant today means more gas generators burning through the 2060s. (I’m assuming we build and deploy solar and wind as quickly as possible, too.)
        pfdietz 2y ago
        > We have power demand growth well ahead of our solar and wind deployment potential Justify that statement, please. What is preventing us from installing that much wind and solar? If anything, nuclear's deployment potential is much more limited.
      - robertlagrant 2y ago
        > Are you saying we should build nuclear now because we didn't then? No, that would be a large comprehension error. I'm making the point because people seem to use what solar and wind can finally do now to justify us not having built nuclear 40 years ago.
- bruce511 2y ago
  Solar and batteries are exploding in production, and prices are falling (not increasing.) I mean, sure, there's a point of diminishing returns, but even at last year's prices I'm getting a 17.5% return on investment. Every year that goes by the investment gets cheaper, and the price of electricity goes up, so the savings just get better and better. And this for a capital spend on equipment with no moving parts, no lubricants, no maintenance schedule (apart from a window-washer a couple times a year.) It's a no brainer if you live anywhere the sun shines well - and LOTS of people have figured this out, so the amounts being installed are moving the needle.
  - interactivecode 2y ago
    plus with every advancement in cost and efficiency the amount of sun needed reduces. If you're a bit more north you might just need a couple extra panels compared to really sunny places. Even if it's just to offset instead of completely replace other fuels
    - haccount 2y ago
      The viability of solar panels in the north depends on eye watering grid prices, which isn't the case everywhere or all of the year. Whenever it occurs it is generally during winter time when a roof worth of panels provides a mere trickle of energy. I considered some small-medium batteries and panels but the calculation came out massively in favor of putting the same bundle of cash into a financial investment portfolio instead.
      - bruce511 2y ago
        I'm 100% with you here (see my comment above about fusion economics.) But solar doesn't have to be local. Upgrading the grid to move large volumes of electricity from mid to high latitudes changes your equation somewhat.
  - JumpCrisscross 2y ago
    > Solar and batteries are exploding in production, and prices are falling Sure. Now look at the baseline. We’d need to 10x the growth rate for the numbers to rival the expected growth in power demand. The folks at the tech majors aren’t idiots. If they could buy this cheapest power at scale, they would. Everybody would. One can’t. The panels are easy, but the batteries are back ordered and getting the land and permitting takes years. I’m in Wyoming. I have seen people spend more time and paperwork getting a wind farm and HVDC line up than an experimental (totally non-economic) nuclear reactor. That doesn’t apply if you’re putting up one windmill to power your off-grid house. But the economics present at that scale diminish when you’re building a fleet of data centre.
deegles 2y ago
I think a few hundred purpose-built nuclear powered CO2 scrubbing plants could be an option. At 1,500 kWh/ton, a 1 GW nuclear plant could capture 5.8 million tons of CO₂ per year which is about 0.015% of global emissions. It would have to be coupled with emissions reductions and so on though.
- epistasis 2y ago
  Is there some advantage to powering this with nuclear rather than other cheaper energy sources? Using waste heat for desorption of amine scrubbers, perhaps?
- idunnoman1222 2y ago
  Or hear me out use the 100 GW of clean energy so that you don’t have to use 100 GW of dirty energy
bruce511 2y ago
I'd add in that my solar panels aren't really all that valuable in themselves. They're bolted to my roof with little more than some bolts and nuts. If I have a "Residential scale" nuclear plant in the basement, there are lots of people who would like to re-purpose my nuclear fuel in other ways. (And that's before we talk about how I purchase, and renew, that fuel to begin with.) Ultimately even "small scale" nuclear comes with massive bureaucratic and security overheads that can't simply be wished away. In closing I'll point out that my solar system _is_ nuclear. It uses fusion nuclear energy as it's fuel. But I've cunningly hidden the radioactive elements far far away....
- blacksmith_tb 2y ago
  It's a good line, but our sun is making nice clean helium out of hydrogen fusion, those nasty radioactive elements are associated with fission (of big unstable isotopes of uranium, plutonium, thorium etc.)
  - bruce511 2y ago
    Yeah I know, but you should never let the facts get in the way of a good story. (And to be fair, all the heavy elements came from the sun (or other suns) to begin with :) More seriously, solar is the closest we'll ever get to fusion power. Assuming we ever get the tech right, it'll simply be too expensive to roll out significant amounts of fusion production. It would require capital that will always give a better return elsewhere. To put it another way, would you rather invest $100 billion in a fusion plant, that'll take 5 years to get permitted and 5 years to build, and require staffing by well trained expensive staff, or spend $10 billion on a solar farm in Africa selling electricity to the US at night which can be up and running in 2 years? Would you be happy to commit your 100 billion today betting that when it comes online 10 to 15 years from now it'll make energy at prices comparable to the solar and storage tech available then? Fusion may indeed be the future. But who's gonna spend the capital to find out?
    - AnthonyMouse 2y ago
      The implicit assumption is that ginormous prototype/research reactors are the only possible way for fusion to work. But if you fund the research, people come up with better lasers and magnets and things. Then you a) have better lasers and magnets and things, which are useful for more than just fusion in the same way that NASA inventions are useful for more than just space exploration; and b) allow the reactors to get smaller: https://www.iflscience.com/baby-fusion-reactor-less-than-a-meter-wide-tops-100-millionc-69216 https://www.iflscience.com/baby-fusion-reactor-less-than-a-m...
hooli42 2y ago
>I would counter that nuclear does not scale in that it can't get small Nuclear can't get small because of social and political reasons, not technical or economics reasons. If you could put a small nuclear reactor in your backyard and it was assured to be safe, would you?
- epistasis 2y ago
  I've never heard that before. I don't think politics would stop a fleet of small 50-100MW replacing a 1GW reactor, and that's certainly not the opposition to SMRs now. It's actually both economic and technical: the technical side makes smaller reactors less economic in terms of efficiency. Thermal generation benefits massively from being really really big.
- philipkglass 2y ago
  It's also due to technical and economic reasons. Tiny reactors require highly enriched fuel and have worse neutron economy and thermal efficiency. You can't use the same low-enriched fuel in a tiny reactor that you can in a typical (hundreds of megawatts or larger) commercial power reactor. In a big commercial power reactor, fuel costs are tiny relative to the total system costs. If you used a tiny reactor like the Kilopower [1] to power a single home, the cost of the highly enriched fuel alone (upward of $50,000 per kilogram, 28 kg in a unit) would be orders of magnitude more expensive than grid-supplied electricity. [1] https://en.wikipedia.org/wiki/Kilopower https://en.wikipedia.org/wiki/Kilopower
- themaninthedark 2y ago
  Yes, especially if I could get heating(winter + hot water) out of the exchange loop.
pfdietz 2y ago
SMRs still require construction, not just manufacturing. NuScale's abortive effort required 1/3rd more labor hours to build per MW than conventional large reactors. You can't pour large concrete structures in a factory.
cameldrv 2y ago
I’d like to understand the economics of size in nuclear reactors better. It seems like there are almost irresistible forces pushing towards bigger reactors. I’m looking particularly at the newish Westinghouse designs. Back in the early 2000s, Westinghouse designed the AP600, 600 megawatts, and it was supposed to have a lot of modularity and factory construction. No one bought one though and so they came out with the AP1000, of which a number have been built. China has now extended the design to the CAP1400 and they’re working on a CAP1700, almost triple the original power.
- JumpCrisscross 2y ago
  > seems like there are almost irresistible forces pushing towards bigger reactors Those advantages go down when you include construction and permitting time (billions of dollars) and transmission costs (billions more over the plant’s lifetime). On SMRs: we don’t know their economics because they don’t practically exist yet. Certainly not in a mass-manufactured flavour.
deleted 2y ago
[deleted]
AnthonyMouse 2y ago
> This is so funny to see, and great to see said, because for decades I ran into nuclear proponents (not engineers or workers, just people into the politics) that said that nuclear was the "only" way to combat climate change The argument that the grid should be 100% nuclear was never really viable. To make it work you would need nuclear to be cheap, so it could be overbuilt to cover hourly and seasonal variation in load. That's theoretically possible, a nuclear reactor is basically a box of hot rocks used to make steam. Large reactors use turbines because they're more efficient, but you can also use steam to run a piston engine and then your cost is approximately the same as a diesel generator only you don't have to buy diesel, just exchange the box of hot rocks for a new one every decade or two. The regulatory environment is not such that this is a thing, however, and then overbuilding nuclear is too expensive. But that's assuming you want to replace the whole grid with nuclear. Any proposal to replace the whole grid with a single generation technology is naive, because the premise would have to be that it's better than all other forms of generation in all contexts. Which isn't true for anything. The big advantage of solar is that it's cheap, if you don't care about consistency -- and sometimes you don't. Solar is great for charging electric cars because they have built-in batteries and then the intermittency doesn't matter. It's pretty good for air conditioning load because that tracks solar output pretty closely. Nuclear is not going to be competitive for those things. But the reverse is true as well. You want to use solar to drive heat pumps at night in winter in regions far from the equator? That's a bad fit, and so is anything else with intermittent power output because if the power goes out people freeze to death. The answer is to build nuclear reactors to power heat pumps and provide cogeneration and build solar to charge electric cars and run air conditioners, instead of trying to do everything with one technology.
- epistasis 2y ago
  Even France didn't get to full replacement of the grid with nuclear, but they got 90% of the way their. Our current mix of tech, even without new nuclear, will get us to 90% decarbonized easily. What we have now that we didn't have 50 years ago is super cheap storage. That's a complete revolution in how to manage grids, and I don't think that the current grid planners and ops know what to do with it yet. You can use storage to avoid transmission congestion, you can use it to time shift, you can use it to avoid distribution node upgrades when you deploy it behind the meter. There are soooooo many ways that storage can reduce grid costs and make it more economically efficient. The challenge is that nearly all grid decisions are made by people that have incentive to keep grid costs as high as possible. We need a new economic and regulatory framework in order to see the benefits of this new technology.
xbmcuser 2y ago
At today’s prices, a Tesla Megapack is estimated to cost about $1 million for 3.9 MWh, or $1 billion for 3.9 GWh. Based on that, my back-of-the-napkin math says the cost of charging and discharging the pack every day for 7+ years would be about $0.10/kWh. That’s at today’s prices, but prices are still falling an average of 12-15% per year. And I’m not convinced that even small-scale nuclear will be cost-competitive in the future, but time will tell.
Gud 2y ago
Sorry, but the “nuclear is too expensive “ argument doesn’t hold up, considering cheap, modern reactors are being built as we speak in countries without a strong political resistance(EU, US). Take the UAE for example, who are experts at large scale energy projects, they have constructed and commissioned 4 nuclear reactors, on time, on budget. To say that it’s not possible, is not true. https://en.wikipedia.org/wiki/Barakah_nuclear_power_plant https://en.wikipedia.org/wiki/Barakah_nuclear_power_plant Full disclosure, I work in the energy sector, world wide, including the UAE. I am also a proponent of solar. Cheap energy replaces the need for manpower.
- philipkglass 2y ago
  Take the UAE for example, who are experts at large scale energy projects, they have constructed and commissioned 4 nuclear reactors, on time, on budget. Your own link says that the first reactor was originally scheduled to start supplying electricity in 2017 but actually entered operation in 2020. It also says "As of 22 March 2018, the project's total cost was refined to $24.4 billion to complete. However, by April 9, 2020, Power Technology reported that the project cost was $32 billion." 3 years late and 30% over budget is OK by nuclear project standards, considering much greater delays and budget blowouts in recent US/EU projects. But it's not on time and on budget.
  - bruce511 2y ago
    It's a huge power plant. 5.6 giga watts. And they did ok with tineline and budget. It did take 12 years of construction, and 32 billion in funding. And they project would have been in development long before construction started. All in a regulatory environment which priorities "getting stuff done" and where there's plenty of capital to invest. (And investors who play a very long game.) There might be conditions somewhere that are more favorable, but its not the US. could it be done? Obviously yes. Will it be done in the US? Not a chance.
  - Gud 2y ago
    Ok, still, the plant now provides a substantial amount of energy to the region. I suspect the pandemic might have provided a cause for the delay. I was myself involved in a large energy project in the UAE and remember the challenges caused by the lockdowns happening. But probably with a 30% over budget bill, that is only partially an explanation. Additionally, the UAE is big users of solar, also having been early adopters of the technology. And like solar, you can build nuclear in small and large scale plants. But my favourite contender for future, base energy source is fusion power, https://www.technologyreview.com/2024/10/31/1106384/inside-a-fusion-energy-facility https://www.technologyreview.com/2024/10/31/1106384/inside-a...

JumpCrisscross 2y ago

> nuclear proponents (not engineers or workers, just people into the politics) that said that nuclear was the "only" way to combat climate change You’re seeing the same nonsense with armchair solar + battery advocates today. The mistake is in assuming marginal advantages persist across scale, i.e. in ignoring the law of diminishing returns. If we could have deployed nuclear immediately and infinitely when those folks were talking, they would have been right. We could t. If we could solar and batteries immediately and infinitely (without increasing prices), going all in on it would be right. We can’t. Most markets optimise heterogenously because that’s what makes sense.

epistasis 2y ago
> If we could have deployed nuclear immediately and infinitely when those folks were talking, they would have been right. We could t. If we are talking about the US, the reason we couldn't deploy nuclear was that we vastly over-ordered the amount of reactors we needed, going into the 1980s, causing a glut then a drought. And then too many of them were financially disastrous construction projects. Some people say that we had too many different reactor designs, but I would point to France where they used the same reactor design but also did not see falling prices, and did not build nearly as many reactors as they had planned. Certainly France has been much better off in terms of carbon emissions from electricity since the 1980s than most places in the world, but they were also going nuclear due to lack of cheap fossil fuels. > If we could solar and batteries immediately and infinitely (without increasing prices), going all in on it would be right. We can’t. If I'm understanding you correctly, you're saying we aren't going all in on solar and storage, but I would argue that we are. Nearly all new generation capacity getting installed is solar, storage, and wind. THere's a few legacy projects for other technologies, but those natural gas plants will see little use, unless solar/storage/batteries are blocked from being deployed in the same area. EIA: https://www.eia.gov/todayinenergy/detail.php?id=62864 https://www.eia.gov/todayinenergy/detail.php?id=62864 This is happening in China too. They build coal plants, but they barely use them as they are just backups. Last I heard they are on track for 160GW of solar deployed this year alone, and it goes up every year. So maybe put me into the bucket of people spouting nonsense about solar + batteries today, I could be wrong, but I really think it's the only tech stack that can and will make a big change in energy over the next 10 years.
- robertlagrant 2y ago
  > Certainly France has been much better off in terms of carbon emissions from electricity since the 1980s than most places in the world, but they were also going nuclear due to lack of cheap fossil fuels. That's the point: 2024's solar is better than 1980's nuclear, but in the meantime we've pumped a lot of CO2 into the atmosphere we didn't have to.
  - pfdietz 2y ago
    It's difficult to see the relevance of your point. Are you saying we should build nuclear now because we didn't then? That would make no sense. This isn't some sort of arena where we have to be fair to inanimate objects.
    - JumpCrisscross 2y ago
      > difficult to see the relevance of your point. Are you saying we should build nuclear now because we didn't then The same statement will be true in twenty years. We’re not building gas generators because they’re pretty. We have power demand growth well ahead of our solar and wind deployment potential, even assuming the rosiest production growth forecasts for the next ten years. That gap is being filled with natural gas, based on infrastructure with 20 to 40-year financing timelines. Not building a nuclear plant today means more gas generators burning through the 2060s. (I’m assuming we build and deploy solar and wind as quickly as possible, too.)
      - pfdietz 2y ago
        > We have power demand growth well ahead of our solar and wind deployment potential Justify that statement, please. What is preventing us from installing that much wind and solar? If anything, nuclear's deployment potential is much more limited.
    - robertlagrant 2y ago
      > Are you saying we should build nuclear now because we didn't then? No, that would be a large comprehension error. I'm making the point because people seem to use what solar and wind can finally do now to justify us not having built nuclear 40 years ago.
bruce511 2y ago
Solar and batteries are exploding in production, and prices are falling (not increasing.) I mean, sure, there's a point of diminishing returns, but even at last year's prices I'm getting a 17.5% return on investment. Every year that goes by the investment gets cheaper, and the price of electricity goes up, so the savings just get better and better. And this for a capital spend on equipment with no moving parts, no lubricants, no maintenance schedule (apart from a window-washer a couple times a year.) It's a no brainer if you live anywhere the sun shines well - and LOTS of people have figured this out, so the amounts being installed are moving the needle.
- interactivecode 2y ago
  plus with every advancement in cost and efficiency the amount of sun needed reduces. If you're a bit more north you might just need a couple extra panels compared to really sunny places. Even if it's just to offset instead of completely replace other fuels
  - haccount 2y ago
    The viability of solar panels in the north depends on eye watering grid prices, which isn't the case everywhere or all of the year. Whenever it occurs it is generally during winter time when a roof worth of panels provides a mere trickle of energy. I considered some small-medium batteries and panels but the calculation came out massively in favor of putting the same bundle of cash into a financial investment portfolio instead.
    - bruce511 2y ago
      I'm 100% with you here (see my comment above about fusion economics.) But solar doesn't have to be local. Upgrading the grid to move large volumes of electricity from mid to high latitudes changes your equation somewhat.
- JumpCrisscross 2y ago
  > Solar and batteries are exploding in production, and prices are falling Sure. Now look at the baseline. We’d need to 10x the growth rate for the numbers to rival the expected growth in power demand. The folks at the tech majors aren’t idiots. If they could buy this cheapest power at scale, they would. Everybody would. One can’t. The panels are easy, but the batteries are back ordered and getting the land and permitting takes years. I’m in Wyoming. I have seen people spend more time and paperwork getting a wind farm and HVDC line up than an experimental (totally non-economic) nuclear reactor. That doesn’t apply if you’re putting up one windmill to power your off-grid house. But the economics present at that scale diminish when you’re building a fleet of data centre.

deegles 2y ago

I think a few hundred purpose-built nuclear powered CO2 scrubbing plants could be an option. At 1,500 kWh/ton, a 1 GW nuclear plant could capture 5.8 million tons of CO₂ per year which is about 0.015% of global emissions. It would have to be coupled with emissions reductions and so on though.

epistasis 2y ago
Is there some advantage to powering this with nuclear rather than other cheaper energy sources? Using waste heat for desorption of amine scrubbers, perhaps?
idunnoman1222 2y ago
Or hear me out use the 100 GW of clean energy so that you don’t have to use 100 GW of dirty energy

bruce511 2y ago

I'd add in that my solar panels aren't really all that valuable in themselves. They're bolted to my roof with little more than some bolts and nuts. If I have a "Residential scale" nuclear plant in the basement, there are lots of people who would like to re-purpose my nuclear fuel in other ways. (And that's before we talk about how I purchase, and renew, that fuel to begin with.) Ultimately even "small scale" nuclear comes with massive bureaucratic and security overheads that can't simply be wished away. In closing I'll point out that my solar system _is_ nuclear. It uses fusion nuclear energy as it's fuel. But I've cunningly hidden the radioactive elements far far away....

blacksmith_tb 2y ago
It's a good line, but our sun is making nice clean helium out of hydrogen fusion, those nasty radioactive elements are associated with fission (of big unstable isotopes of uranium, plutonium, thorium etc.)
- bruce511 2y ago
  Yeah I know, but you should never let the facts get in the way of a good story. (And to be fair, all the heavy elements came from the sun (or other suns) to begin with :) More seriously, solar is the closest we'll ever get to fusion power. Assuming we ever get the tech right, it'll simply be too expensive to roll out significant amounts of fusion production. It would require capital that will always give a better return elsewhere. To put it another way, would you rather invest $100 billion in a fusion plant, that'll take 5 years to get permitted and 5 years to build, and require staffing by well trained expensive staff, or spend $10 billion on a solar farm in Africa selling electricity to the US at night which can be up and running in 2 years? Would you be happy to commit your 100 billion today betting that when it comes online 10 to 15 years from now it'll make energy at prices comparable to the solar and storage tech available then? Fusion may indeed be the future. But who's gonna spend the capital to find out?
  - AnthonyMouse 2y ago
    The implicit assumption is that ginormous prototype/research reactors are the only possible way for fusion to work. But if you fund the research, people come up with better lasers and magnets and things. Then you a) have better lasers and magnets and things, which are useful for more than just fusion in the same way that NASA inventions are useful for more than just space exploration; and b) allow the reactors to get smaller: https://www.iflscience.com/baby-fusion-reactor-less-than-a-meter-wide-tops-100-millionc-69216 https://www.iflscience.com/baby-fusion-reactor-less-than-a-m...

hooli42 2y ago

>I would counter that nuclear does not scale in that it can't get small Nuclear can't get small because of social and political reasons, not technical or economics reasons. If you could put a small nuclear reactor in your backyard and it was assured to be safe, would you?

epistasis 2y ago
I've never heard that before. I don't think politics would stop a fleet of small 50-100MW replacing a 1GW reactor, and that's certainly not the opposition to SMRs now. It's actually both economic and technical: the technical side makes smaller reactors less economic in terms of efficiency. Thermal generation benefits massively from being really really big.
philipkglass 2y ago
It's also due to technical and economic reasons. Tiny reactors require highly enriched fuel and have worse neutron economy and thermal efficiency. You can't use the same low-enriched fuel in a tiny reactor that you can in a typical (hundreds of megawatts or larger) commercial power reactor. In a big commercial power reactor, fuel costs are tiny relative to the total system costs. If you used a tiny reactor like the Kilopower [1] to power a single home, the cost of the highly enriched fuel alone (upward of $50,000 per kilogram, 28 kg in a unit) would be orders of magnitude more expensive than grid-supplied electricity. [1] https://en.wikipedia.org/wiki/Kilopower https://en.wikipedia.org/wiki/Kilopower
themaninthedark 2y ago
Yes, especially if I could get heating(winter + hot water) out of the exchange loop.

pfdietz 2y ago

SMRs still require construction, not just manufacturing. NuScale's abortive effort required 1/3rd more labor hours to build per MW than conventional large reactors. You can't pour large concrete structures in a factory.

cameldrv 2y ago

I’d like to understand the economics of size in nuclear reactors better. It seems like there are almost irresistible forces pushing towards bigger reactors. I’m looking particularly at the newish Westinghouse designs. Back in the early 2000s, Westinghouse designed the AP600, 600 megawatts, and it was supposed to have a lot of modularity and factory construction. No one bought one though and so they came out with the AP1000, of which a number have been built. China has now extended the design to the CAP1400 and they’re working on a CAP1700, almost triple the original power.

JumpCrisscross 2y ago
> seems like there are almost irresistible forces pushing towards bigger reactors Those advantages go down when you include construction and permitting time (billions of dollars) and transmission costs (billions more over the plant’s lifetime). On SMRs: we don’t know their economics because they don’t practically exist yet. Certainly not in a mass-manufactured flavour.

deleted 2y ago

[deleted]

AnthonyMouse 2y ago

> This is so funny to see, and great to see said, because for decades I ran into nuclear proponents (not engineers or workers, just people into the politics) that said that nuclear was the "only" way to combat climate change The argument that the grid should be 100% nuclear was never really viable. To make it work you would need nuclear to be cheap, so it could be overbuilt to cover hourly and seasonal variation in load. That's theoretically possible, a nuclear reactor is basically a box of hot rocks used to make steam. Large reactors use turbines because they're more efficient, but you can also use steam to run a piston engine and then your cost is approximately the same as a diesel generator only you don't have to buy diesel, just exchange the box of hot rocks for a new one every decade or two. The regulatory environment is not such that this is a thing, however, and then overbuilding nuclear is too expensive. But that's assuming you want to replace the whole grid with nuclear. Any proposal to replace the whole grid with a single generation technology is naive, because the premise would have to be that it's better than all other forms of generation in all contexts. Which isn't true for anything. The big advantage of solar is that it's cheap, if you don't care about consistency -- and sometimes you don't. Solar is great for charging electric cars because they have built-in batteries and then the intermittency doesn't matter. It's pretty good for air conditioning load because that tracks solar output pretty closely. Nuclear is not going to be competitive for those things. But the reverse is true as well. You want to use solar to drive heat pumps at night in winter in regions far from the equator? That's a bad fit, and so is anything else with intermittent power output because if the power goes out people freeze to death. The answer is to build nuclear reactors to power heat pumps and provide cogeneration and build solar to charge electric cars and run air conditioners, instead of trying to do everything with one technology.

epistasis 2y ago
Even France didn't get to full replacement of the grid with nuclear, but they got 90% of the way their. Our current mix of tech, even without new nuclear, will get us to 90% decarbonized easily. What we have now that we didn't have 50 years ago is super cheap storage. That's a complete revolution in how to manage grids, and I don't think that the current grid planners and ops know what to do with it yet. You can use storage to avoid transmission congestion, you can use it to time shift, you can use it to avoid distribution node upgrades when you deploy it behind the meter. There are soooooo many ways that storage can reduce grid costs and make it more economically efficient. The challenge is that nearly all grid decisions are made by people that have incentive to keep grid costs as high as possible. We need a new economic and regulatory framework in order to see the benefits of this new technology.

xbmcuser 2y ago

At today’s prices, a Tesla Megapack is estimated to cost about $1 million for 3.9 MWh, or $1 billion for 3.9 GWh. Based on that, my back-of-the-napkin math says the cost of charging and discharging the pack every day for 7+ years would be about $0.10/kWh. That’s at today’s prices, but prices are still falling an average of 12-15% per year. And I’m not convinced that even small-scale nuclear will be cost-competitive in the future, but time will tell.

Gud 2y ago

Sorry, but the “nuclear is too expensive “ argument doesn’t hold up, considering cheap, modern reactors are being built as we speak in countries without a strong political resistance(EU, US). Take the UAE for example, who are experts at large scale energy projects, they have constructed and commissioned 4 nuclear reactors, on time, on budget. To say that it’s not possible, is not true. https://en.wikipedia.org/wiki/Barakah_nuclear_power_plant https://en.wikipedia.org/wiki/Barakah_nuclear_power_plant Full disclosure, I work in the energy sector, world wide, including the UAE. I am also a proponent of solar. Cheap energy replaces the need for manpower.

philipkglass 2y ago
Take the UAE for example, who are experts at large scale energy projects, they have constructed and commissioned 4 nuclear reactors, on time, on budget. Your own link says that the first reactor was originally scheduled to start supplying electricity in 2017 but actually entered operation in 2020. It also says "As of 22 March 2018, the project's total cost was refined to $24.4 billion to complete. However, by April 9, 2020, Power Technology reported that the project cost was $32 billion." 3 years late and 30% over budget is OK by nuclear project standards, considering much greater delays and budget blowouts in recent US/EU projects. But it's not on time and on budget.
- bruce511 2y ago
  It's a huge power plant. 5.6 giga watts. And they did ok with tineline and budget. It did take 12 years of construction, and 32 billion in funding. And they project would have been in development long before construction started. All in a regulatory environment which priorities "getting stuff done" and where there's plenty of capital to invest. (And investors who play a very long game.) There might be conditions somewhere that are more favorable, but its not the US. could it be done? Obviously yes. Will it be done in the US? Not a chance.
- Gud 2y ago
  Ok, still, the plant now provides a substantial amount of energy to the region. I suspect the pandemic might have provided a cause for the delay. I was myself involved in a large energy project in the UAE and remember the challenges caused by the lockdowns happening. But probably with a 30% over budget bill, that is only partially an explanation. Additionally, the UAE is big users of solar, also having been early adopters of the technology. And like solar, you can build nuclear in small and large scale plants. But my favourite contender for future, base energy source is fusion power, https://www.technologyreview.com/2024/10/31/1106384/inside-a-fusion-energy-facility https://www.technologyreview.com/2024/10/31/1106384/inside-a...