3 ms·

Oh, it's the NuScale guy again. NuScale got far enough to get approval to build a test reactor at the Idaho Reactor Testing Station, which is in Outer Nowhere

Oh, it's the NuScale guy again. NuScale got far enough to get approval to build a test reactor at the Idaho Reactor Testing Station, which is in Outer Nowhere for good reasons. But they never got enough funding to build it. The trouble with most of these small modular reactor schemes is that their big pitch is mostly "we don't need a big, strong, containment vessel because ... reasons." There's no inherent problem in building a small nuclear reactor. Here's one from 1957, near Oakland, CA.[1] It's safety if something goes badly wrong that's a problem. History: - Chernobyl - meltdown and fire, no containment vessel, major disaster. - Fukushima - meltdown, too-small containment vessel, large disaster. - Three Mile Island - meltdown, big strong containment vessel, plant lost but no disaster. Alternative reactor history: - Fort St. Vrain - high temperature gas-cooled, subject to helium plumbing leaks in radioactive zone, shut down and plant converted to natural gas. - AVR reactor, Germany - pebble bed reactor, had pebble jam, had to be shut down, extremely difficult to decommission. - Sodium reactors - prone to fires.[3] - Molten salt reactors [4] - require an attached chemical plant that reprocesses radioactive molten salt. Most of the problems of nuclear reactors in practice involve plumbing. Everything in the radioactive zone has to last half a century or so without maintenance. That's possible with distilled water as the working fluid, but everything else tried has not worked well. [1] https://www.youtube.com/watch?v=A1O8xAB_FDI https://www.youtube.com/watch?v=A1O8xAB_FDI [2] https://en.wikipedia.org/wiki/AVR_reactor https://en.wikipedia.org/wiki/AVR_reactor [3] https://www.nuclearsafety.gc.ca/eng/resources/research/technical-papers-and-articles/2019/overview-of-liquid-sodium-fires/ https://www.nuclearsafety.gc.ca/eng/resources/research/techn... [4] https://en.wikipedia.org/wiki/Molten-salt_reactor https://en.wikipedia.org/wiki/Molten-salt_reactor

concordDance 2y ago
> Fukushima - meltdown, too-small containment vessel, large disaster. Probably overselling the "large" there... at least on the scale of global power production.
- lostlogin 2y ago
  You wouldn’t call Fukushima a large disaster? The financial cost is at $180 billion US. That seems large.
  - jenadine 2y ago
    According to https://en.m.wikipedia.org/wiki/Nuclear_power_in_Japan https://en.m.wikipedia.org/wiki/Nuclear_power_in_Japan , Japan had about 300 TWh of nuclear for a year at the time of the accident. So $180 billion amount to $0.6/kWh over a year if I'm not mistaken. Not cheap. But if you spread over a few decades then that's reasonable.
    - lostlogin 2y ago
      > $0.6/kWh I must be messing something up, as that’s about 3-4x what I pay for electricity and seems a lot?
  - concordDance 2y ago
    Sadly I don't have time to go into it now, but they're massively overpaying due to miscallibrated risk tolerance. (Paying tens of millions per QALY is not a good use of money, 1 milliSv per year is an utterly insane goal) The actual disaster had noticably bad short term effects on only a small area and long term effects on a tiny area.
  - natmaka 2y ago
    Nobody knows for sure, but the sole nuclear accident cleanup operations may cost $470 to $660 billion. https://en.wikipedia.org/wiki/Fukushima_nuclear_accident_cleanup#Costs_of_the_cleanup_operations https://en.wikipedia.org/wiki/Fukushima_nuclear_accident_cle...
perihelions 2y ago
- "That's possible with distilled water as the working fluid" Distilled water is pretty corrosive at high temperatures, isn't it? I'm no engineer but I've read that the water-chemistry management of nuclear reactors is a highly finicky topic. Here's a crazy fact I can't get out of my head: the PWR types of reactors rely on lithium hydroxide in their nuclear water pipes, as a critical corrosion inhibitor. But the US can't make this (meaning, the isotopically enriched lithium of the correct flavor for nuclear reactors); it imports 100% of this key ingredient from foreign countries— currently, exclusively, China and Russia. Our top geopolitical adversaries could kneecap most of our nuclear power fleet, if they wanted, because of the difficult engineering minutae of "water is corrosive". True story. https://www.gao.gov/products/gao-13-716 https://www.gao.gov/products/gao-13-716
themaninthedark 2y ago
Where did you see that the containment at Fukushima was too small? I thought that most of the release was done because there was not enough storage of contaminated water.
- Animats 2y ago
  Fukishima containment.[1] The top of the containment vessel is shown in yellow, just above the red cylinder containing the reactor. The containment vessel was a heavy shell, but not much larger than the reactor. It had to contain any steam overpressure resulting from an accident, and didn't have enough volume that the steam pressure would decrease, and maybe condense. The surrounding building wasn't a pressure vessel and couldn't contain anything. Building panels blew out, leaving visible holes in the walls. Three Mile Island containment.[2] The entire huge concrete and steel building around the reactor and support equipment is the containment vessel. When the reactor failed, radioactive steam escaped into the large containment vessel, where it was contained. [1] https://world-nuclear.org/information-library/appendices/fukushima-reactor-background https://world-nuclear.org/information-library/appendices/fuk... [2] https://www.ans.org/news/article-3916/the-three-mile-island-special-report/ https://www.ans.org/news/article-3916/the-three-mile-island-...
  - themaninthedark 2y ago
    Thanks!
AlotOfReading 2y ago
The vallecitos reactor site is still there to look for anyone in the bay area, at least for the next few years. It's along the 680 corridor just south of Pleasanton and it's been quietly producing medical isotopes since the 70s. They shut down the power factors after they discovered that the entire Pleasanton valley is a gigantic active fault zone called the calaveras fault, and the site itself is in a rift from from another, smaller fault called the positas fault. Probably not the greatest placement in hindsight.
- Animats 2y ago
  The long de-fueled reactor vessel was removed just last year.[1] Sent to Texas as a final resting place. The containment dome was still in place then. The next step is to restore the Vallecitos complex to "conditions suitable for productive reuse for other commercial or industrial purposes."[2] So that's the aftermath of the first commercial small nuclear power reactor. [1] https://www.world-nuclear-news.org/Articles/Vallecitos-reactor-removal-complete https://www.world-nuclear-news.org/Articles/Vallecitos-react... [2] https://www.northstar.com/northstar-closes-ge-hitachi-vallecitos-nuclear-center-decommissioning-deal/ https://www.northstar.com/northstar-closes-ge-hitachi-vallec...
epistasis 2y ago
> But they never got enough funding to build it. It's worth examining why they never went forward with builds. In 2023 their cost estimates for power went from a manageable $55/MWh to a barely-managable $93/MWh. And that was before all the additional cost increases that are typical for first projects. They were unable to paint a story that was financially compelling. Nuclear's problems are not TMI, it's Summer, and other failed builds. The government will insure catastrophic damages. It will not insure against construction cost overruns, and those may not kill people but they kill companies dead.

concordDance 2y ago

> Fukushima - meltdown, too-small containment vessel, large disaster. Probably overselling the "large" there... at least on the scale of global power production.

lostlogin 2y ago
You wouldn’t call Fukushima a large disaster? The financial cost is at $180 billion US. That seems large.
- jenadine 2y ago
  According to https://en.m.wikipedia.org/wiki/Nuclear_power_in_Japan https://en.m.wikipedia.org/wiki/Nuclear_power_in_Japan , Japan had about 300 TWh of nuclear for a year at the time of the accident. So $180 billion amount to $0.6/kWh over a year if I'm not mistaken. Not cheap. But if you spread over a few decades then that's reasonable.
  - lostlogin 2y ago
    > $0.6/kWh I must be messing something up, as that’s about 3-4x what I pay for electricity and seems a lot?
- concordDance 2y ago
  Sadly I don't have time to go into it now, but they're massively overpaying due to miscallibrated risk tolerance. (Paying tens of millions per QALY is not a good use of money, 1 milliSv per year is an utterly insane goal) The actual disaster had noticably bad short term effects on only a small area and long term effects on a tiny area.
- natmaka 2y ago
  Nobody knows for sure, but the sole nuclear accident cleanup operations may cost $470 to $660 billion. https://en.wikipedia.org/wiki/Fukushima_nuclear_accident_cleanup#Costs_of_the_cleanup_operations https://en.wikipedia.org/wiki/Fukushima_nuclear_accident_cle...

perihelions 2y ago

- "That's possible with distilled water as the working fluid" Distilled water is pretty corrosive at high temperatures, isn't it? I'm no engineer but I've read that the water-chemistry management of nuclear reactors is a highly finicky topic. Here's a crazy fact I can't get out of my head: the PWR types of reactors rely on lithium hydroxide in their nuclear water pipes, as a critical corrosion inhibitor. But the US can't make this (meaning, the isotopically enriched lithium of the correct flavor for nuclear reactors); it imports 100% of this key ingredient from foreign countries— currently, exclusively, China and Russia. Our top geopolitical adversaries could kneecap most of our nuclear power fleet, if they wanted, because of the difficult engineering minutae of "water is corrosive". True story. https://www.gao.gov/products/gao-13-716 https://www.gao.gov/products/gao-13-716

themaninthedark 2y ago

Where did you see that the containment at Fukushima was too small? I thought that most of the release was done because there was not enough storage of contaminated water.

Animats 2y ago
Fukishima containment.[1] The top of the containment vessel is shown in yellow, just above the red cylinder containing the reactor. The containment vessel was a heavy shell, but not much larger than the reactor. It had to contain any steam overpressure resulting from an accident, and didn't have enough volume that the steam pressure would decrease, and maybe condense. The surrounding building wasn't a pressure vessel and couldn't contain anything. Building panels blew out, leaving visible holes in the walls. Three Mile Island containment.[2] The entire huge concrete and steel building around the reactor and support equipment is the containment vessel. When the reactor failed, radioactive steam escaped into the large containment vessel, where it was contained. [1] https://world-nuclear.org/information-library/appendices/fukushima-reactor-background https://world-nuclear.org/information-library/appendices/fuk... [2] https://www.ans.org/news/article-3916/the-three-mile-island-special-report/ https://www.ans.org/news/article-3916/the-three-mile-island-...
- themaninthedark 2y ago
  Thanks!

AlotOfReading 2y ago

The vallecitos reactor site is still there to look for anyone in the bay area, at least for the next few years. It's along the 680 corridor just south of Pleasanton and it's been quietly producing medical isotopes since the 70s. They shut down the power factors after they discovered that the entire Pleasanton valley is a gigantic active fault zone called the calaveras fault, and the site itself is in a rift from from another, smaller fault called the positas fault. Probably not the greatest placement in hindsight.

Animats 2y ago
The long de-fueled reactor vessel was removed just last year.[1] Sent to Texas as a final resting place. The containment dome was still in place then. The next step is to restore the Vallecitos complex to "conditions suitable for productive reuse for other commercial or industrial purposes."[2] So that's the aftermath of the first commercial small nuclear power reactor. [1] https://www.world-nuclear-news.org/Articles/Vallecitos-reactor-removal-complete https://www.world-nuclear-news.org/Articles/Vallecitos-react... [2] https://www.northstar.com/northstar-closes-ge-hitachi-vallecitos-nuclear-center-decommissioning-deal/ https://www.northstar.com/northstar-closes-ge-hitachi-vallec...

epistasis 2y ago

> But they never got enough funding to build it. It's worth examining why they never went forward with builds. In 2023 their cost estimates for power went from a manageable $55/MWh to a barely-managable $93/MWh. And that was before all the additional cost increases that are typical for first projects. They were unable to paint a story that was financially compelling. Nuclear's problems are not TMI, it's Summer, and other failed builds. The government will insure catastrophic damages. It will not insure against construction cost overruns, and those may not kill people but they kill companies dead.