4 ms·

I suspect a large portion of it is how to make those components sufficiently silent to be useful on a military submarine, where sonar is your enemy's primary wa

I suspect a large portion of it is how to make those components sufficiently silent to be useful on a military submarine, where sonar is your enemy's primary way of finding you. how to build a nuclear reactor is relatively well-known. but, how do you make a silent nuclear reactor? that's really only useful for a submarine. it wouldn't surprise me if existing commercial reactor designs would need to be completely redesigned for submarine use. for an example of how much research goes into making subs silent, there is a very deep lake in Idaho the US Navy has used for acoustic testing since World War 2 [0] the navy also has almost 70 years [1] of operational experience with nuclear reactors on subs. I imagine there's a enormous pile of "minor" things they've figured out as they chase down every last source of uncontrolled noise on the boat. 0: https://jalopnik.com/the-navys-most-vital-and-secretive-submarine-base-is-in-1590794426 https://jalopnik.com/the-navys-most-vital-and-secretive-subm... 1: https://en.wikipedia.org/wiki/USS_Nautilus_(SSN-571) https://en.wikipedia.org/wiki/USS_Nautilus_(SSN-571)

antognini 5y ago
And a silent nuclear submarine can run without needing to resurface for far longer than a conventional diesel sub. This is why AUKUS was such a big deal. With diesel subs, Australia could venture out into the South China Sea for 11 days. Once they have nuclear submarines they can remain there for 77. With diesel subs they couldn't reach the East China Sea, but with nuclear subs they can stay there for up to 73 days. https://www.economist.com/img/b/640/724/90/sites/default/files/images/print-edition/20210925_FBM960.png https://www.economist.com/img/b/640/724/90/sites/default/fil...
- sofixa 5y ago
  It would have been nice from Australia to realise that from the start and not start a procurement program for a diesel-electric sub, and pick the diesel-electric version of a nuclear sub to boot.
  - WastingMyTime89 5y ago
    Diesel-electric sub have advantage if you want sub to do costs protection. They are more silent and can remain in position for a long time as they don't need to move to cool their reactor. It means they can stay in pockets of silence longer if they need to(sub exploit variation of pressure, salt density and temperature underwater to find place where their sound waves diffuse poorly). Honestly Australia doesn't need nuclear sub. The only things they can do that diesel-electric sub couldn't is offensive missions in water further for the Australian costs. That might be useful if Australia decides to go fight in an hypothetical war against China but that would mostly serve the interest of the USA. Diesel-electric was probably a better choice because Australia would have been able to service them. As is, they will be bound to the USA.
    - kryogen1c 5y ago
      > need to move to cool their reactor why do you think nuclear subs have to be moving to cool the reactor?
      - WastingMyTime89 5y ago
        They can pump water but it's noisy and when they don't move all the warm water they generate stay above them and they become easy to spot from the surface. Meanwhile a diesel-electric sub can just stay on batteries and is then close to entierely silent.

antognini 5y ago

And a silent nuclear submarine can run without needing to resurface for far longer than a conventional diesel sub. This is why AUKUS was such a big deal. With diesel subs, Australia could venture out into the South China Sea for 11 days. Once they have nuclear submarines they can remain there for 77. With diesel subs they couldn't reach the East China Sea, but with nuclear subs they can stay there for up to 73 days. https://www.economist.com/img/b/640/724/90/sites/default/files/images/print-edition/20210925_FBM960.png https://www.economist.com/img/b/640/724/90/sites/default/fil...

sofixa 5y ago
It would have been nice from Australia to realise that from the start and not start a procurement program for a diesel-electric sub, and pick the diesel-electric version of a nuclear sub to boot.
- WastingMyTime89 5y ago
  Diesel-electric sub have advantage if you want sub to do costs protection. They are more silent and can remain in position for a long time as they don't need to move to cool their reactor. It means they can stay in pockets of silence longer if they need to(sub exploit variation of pressure, salt density and temperature underwater to find place where their sound waves diffuse poorly). Honestly Australia doesn't need nuclear sub. The only things they can do that diesel-electric sub couldn't is offensive missions in water further for the Australian costs. That might be useful if Australia decides to go fight in an hypothetical war against China but that would mostly serve the interest of the USA. Diesel-electric was probably a better choice because Australia would have been able to service them. As is, they will be bound to the USA.
  - kryogen1c 5y ago
    > need to move to cool their reactor why do you think nuclear subs have to be moving to cool the reactor?
    - WastingMyTime89 5y ago
      They can pump water but it's noisy and when they don't move all the warm water they generate stay above them and they become easy to spot from the surface. Meanwhile a diesel-electric sub can just stay on batteries and is then close to entierely silent.