4 ms·

It will be interesting to see a modern design, rather that the something based on 1930s physics, 1940s construction methods, built in the 1950s and put into use

It will be interesting to see a modern design, rather that the something based on 1930s physics, 1940s construction methods, built in the 1950s and put into use in the 1960s like some of these military reactors they used for remote bases.

aynyc 4y ago
No matter the design, it’ll be built by lowest bidders around the world. /s
- throwaway4aday 4y ago
  Any evidence that high bidders do a better job?
- simonh 4y ago
  Clearly you have never heard of cost plus contracts.
wongarsu 4y ago
"Rolls-Royce plan to have a reactor ready to send to the Moon by 2029". With that deadline I would expect something closer to a proven submarine reactor adapted for an environment without abundant water and fewer convenient ways to get rid of heat.
- bayesian_horse 4y ago
  I'd think a similar design, or at least at a similar scale, would get ruled out by the necessary shielding. That would be quite a lot of mass to land on the moon. Some innovation is in order. Mass reduction and radiation safety are among the highest design priorities I'd say.
  - imglorp 4y ago
    In flight, it can be shielded with water and polyethylene, which would be needed anyway by colonists. On the surface, as someone else noted, you want good ground contact for heat dissipation so you might as well throw it into a hole and bury it, dirt being plentiful.
- mikepurvis 4y ago
  Once you're on the surface you can sink a fair bit of heat into the ground. The issue in space is that you can't do convection, and there's nothing to conduct to, so you're really just left with giant, inefficient radiators.
  - ambicapter 4y ago
    Nitpick: Are radiators very inefficient? I assume they're 100% efficient, just not very effective due to the limits of physics.
    - brokencode 4y ago
      Depends on what you mean by efficient. I assume the previous commenter meant it isn’t efficient in terms of cost and space to build large radiators that aren’t very effective.
      - mikepurvis 4y ago
        Yes, efficiency here is in the sense of the mass and volume of device required to dissipate X amount of heat energy, particularly in an environment where getting a lot of mass and volume up there is fabulously expensive.
    - go_elmo 4y ago
      Not a physicist, but I'd say it depends on what you define as parameter optimized against. For space, Id be interested in heat energy dissipated per unit time per kimogram per cargospace for exanple, where radiators suck compared to convection coolers
    - deleted 4y ago
      [deleted]
  - helsinkiandrew 4y ago
    On the moon, wouldn’t heat be a useful byproduct? (At least during the night) so a combined heat and power station would put those radiators where the people are
- huijzer 4y ago
  NuScale also still plans on a first reactor by 2027 even though are ahead in the small nuclear reactor space
  - akvadrako 4y ago
    Small nuclear reactors are not proven though and are quite a risky idea since nuclear benefits significantly from scale. If your goal is to produce something that's useful in a short time span, it's better to use proven tech.
    - pvaldes 4y ago
      The moon is being bombed routinely with space debris so technically is an interesting engineering problem. The same meteorites that create craters in the moon would fall over a nuclear plant so I assume that would need to be put in the face of the moon that is closer to Earth. Otherwise this would mean having several local areas of the moon contaminated and forbidden forever in a few years. Not wind, animals or water in the moon, so apart of the ejected dust, radioactivity should remain in the same place at least
      - evgen 4y ago
        Given the complete lack of shielding that we get from the magnetosphere and atmosphere I am guessing that a few kg of scattered enriched uranium is going to be background noise on the moon. The target is small, the moon is (relatively) big and we can bury the reactor; a meteor strike on the reactor is probably less of a concern than a similar strike on any habitat to which the reactor it meant to provide power. A recent Chinese probe has shown that lunar regolith is radioactive just from cosmic ray bombardment, so as a general rule I am guessing that future lunar operations will treat the entire lunar environment the same way we treat places like Chernobyl. Shield everything, watch your dosage and exposure, and do everything possible to prevent inhalation/ingestion of particles from the external environment.
  - Gwypaas 4y ago
    At incredibly high cost. https://www.wired.com/story/the-dream-of-mini-nuclear-plants-hangs-in-the-balance/amp https://www.wired.com/story/the-dream-of-mini-nuclear-plants...
- simonh 4y ago
  Since RR make submarine nuclear reactors for the UK's fleet already, yes.
- hulitu 4y ago
  Heat , what heat ? I've heard that the moon is cold.
helsinkiandrew 4y ago
Presumably this will be a version of Rolls Royces PWR based modular reactors, which are versions of their reactors used in U.K. (and soon AUS) submarines https://www.rolls-royce.com/innovation/net-zero/decarbonising-complex-critical-systems/small-nuclear-power-stations.aspx https://www.rolls-royce.com/innovation/net-zero/decarbonisin...

aynyc 4y ago

No matter the design, it’ll be built by lowest bidders around the world. /s

throwaway4aday 4y ago
Any evidence that high bidders do a better job?
simonh 4y ago
Clearly you have never heard of cost plus contracts.

wongarsu 4y ago

"Rolls-Royce plan to have a reactor ready to send to the Moon by 2029". With that deadline I would expect something closer to a proven submarine reactor adapted for an environment without abundant water and fewer convenient ways to get rid of heat.

bayesian_horse 4y ago
I'd think a similar design, or at least at a similar scale, would get ruled out by the necessary shielding. That would be quite a lot of mass to land on the moon. Some innovation is in order. Mass reduction and radiation safety are among the highest design priorities I'd say.
- imglorp 4y ago
  In flight, it can be shielded with water and polyethylene, which would be needed anyway by colonists. On the surface, as someone else noted, you want good ground contact for heat dissipation so you might as well throw it into a hole and bury it, dirt being plentiful.
mikepurvis 4y ago
Once you're on the surface you can sink a fair bit of heat into the ground. The issue in space is that you can't do convection, and there's nothing to conduct to, so you're really just left with giant, inefficient radiators.
- ambicapter 4y ago
  Nitpick: Are radiators very inefficient? I assume they're 100% efficient, just not very effective due to the limits of physics.
  - brokencode 4y ago
    Depends on what you mean by efficient. I assume the previous commenter meant it isn’t efficient in terms of cost and space to build large radiators that aren’t very effective.
    - mikepurvis 4y ago
      Yes, efficiency here is in the sense of the mass and volume of device required to dissipate X amount of heat energy, particularly in an environment where getting a lot of mass and volume up there is fabulously expensive.
  - go_elmo 4y ago
    Not a physicist, but I'd say it depends on what you define as parameter optimized against. For space, Id be interested in heat energy dissipated per unit time per kimogram per cargospace for exanple, where radiators suck compared to convection coolers
  - deleted 4y ago
    [deleted]
- helsinkiandrew 4y ago
  On the moon, wouldn’t heat be a useful byproduct? (At least during the night) so a combined heat and power station would put those radiators where the people are
huijzer 4y ago
NuScale also still plans on a first reactor by 2027 even though are ahead in the small nuclear reactor space
- akvadrako 4y ago
  Small nuclear reactors are not proven though and are quite a risky idea since nuclear benefits significantly from scale. If your goal is to produce something that's useful in a short time span, it's better to use proven tech.
  - pvaldes 4y ago
    The moon is being bombed routinely with space debris so technically is an interesting engineering problem. The same meteorites that create craters in the moon would fall over a nuclear plant so I assume that would need to be put in the face of the moon that is closer to Earth. Otherwise this would mean having several local areas of the moon contaminated and forbidden forever in a few years. Not wind, animals or water in the moon, so apart of the ejected dust, radioactivity should remain in the same place at least
    - evgen 4y ago
      Given the complete lack of shielding that we get from the magnetosphere and atmosphere I am guessing that a few kg of scattered enriched uranium is going to be background noise on the moon. The target is small, the moon is (relatively) big and we can bury the reactor; a meteor strike on the reactor is probably less of a concern than a similar strike on any habitat to which the reactor it meant to provide power. A recent Chinese probe has shown that lunar regolith is radioactive just from cosmic ray bombardment, so as a general rule I am guessing that future lunar operations will treat the entire lunar environment the same way we treat places like Chernobyl. Shield everything, watch your dosage and exposure, and do everything possible to prevent inhalation/ingestion of particles from the external environment.
- Gwypaas 4y ago
  At incredibly high cost. https://www.wired.com/story/the-dream-of-mini-nuclear-plants-hangs-in-the-balance/amp https://www.wired.com/story/the-dream-of-mini-nuclear-plants...
simonh 4y ago
Since RR make submarine nuclear reactors for the UK's fleet already, yes.
hulitu 4y ago
Heat , what heat ? I've heard that the moon is cold.

helsinkiandrew 4y ago

Presumably this will be a version of Rolls Royces PWR based modular reactors, which are versions of their reactors used in U.K. (and soon AUS) submarines https://www.rolls-royce.com/innovation/net-zero/decarbonising-complex-critical-systems/small-nuclear-power-stations.aspx https://www.rolls-royce.com/innovation/net-zero/decarbonisin...