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The Navy spends uses lots of people to run reactors on ships and spends tons of money training them. Small reactors won't be economical if they take that many

The Navy spends uses lots of people to run reactors on ships and spends tons of money training them. Small reactors won't be economical if they take that many people to run. Also, naval reactors aren't small. Aircraft carriers have two 250 MW (700 MW thermal) reactors. That is a respectable power plant and much larger than proposed modular reactors.

adolph 3y ago
> Small reactors won't be economical if they take that many people to run. What are the numbers? What’s the TCO difference to similar systems without atmospheric carbon emissions?
- kibwen 3y ago
  The US Navy doesn't use nuclear reactors because of economics (they're quite expensive) or environmental concern. They use nukes because of the operational advantages of having a ship that only needs refueling once per decade. Any comparison to the naval use case is mostly useless when it comes to commercial power production.
  - Alupis 3y ago
    *Once per ~30 years[1], to be pedantic. The reasons are not simply refueling concerns, although that is a factor. The boats still need to refuel the humans onboard, ie. food supplies and occasionally munitions. The reactor powers the boat using less mass than a typical diesel-electric, is more quiet, and can remain underwater for an entire deployment if necessary - something that's simply not possible with other power generation methods. [1] https://en.wikipedia.org/wiki/Virginia-class_submarine#:~:text=Specifications,-Lead%20boat%20Virginia&text=Propulsion%3A%20S9G%20nuclear%20reactor%20delivering,fuel%20manufactured%20by%20BWX%20Technologies https://en.wikipedia.org/wiki/Virginia-class_submarine#:~:te....
    - krisoft 3y ago
      > and can remain underwater for an entire deployment if necessary To be absolutely pedantic not all US navy reactors are on submarines. They also power surface ships with them.
  - adolph 3y ago
    The claim is “Small reactors won't be economical if they take that many people [as the US Navy] to run.” The question is “What are the numbers?” Clearly the navy uses nukes due to advantageous performance characteristics. What are the numbers that a civilian small nuke must make to be viable?
    - nukeman 3y ago
      Quantity. One of the big issues with nuclear power is that we aren’t building frequently enough, and therefore lose expertise and capability, which drives up costs, both from screw-ups and from not being able to amortize over a large production run. To give an analogy, imagine if Boeing only made one 737 every five years. That aircraft would be insanely expensive. Personally, I’m bullish on the companies in the micro reactor space that have minimal site construction. I’m less bullish on Oklo, given that their application had some glaring omissions and got denied an NRC license.
Alupis 3y ago
> Also, naval reactors aren't small. Aircraft carriers have two 250 MW (700 MW thermal) reactors. Everything is relative - but there's vastly more nuclear powered submarines than aircraft carriers. The Virginia Class, for example, is powered by a single 30MW reactor[1]. The article states these "microreactors" will range from 15MW to 100MW. The "Nukes" in the Navy are highly trained, yes, but a military environment is going to be far rougher than anything privately managed for land-side power generation. [1] https://en.wikipedia.org/wiki/Virginia-class_submarine#:~:text=Specifications,-Lead%20boat%20Virginia&text=Propulsion%3A%20S9G%20nuclear%20reactor%20delivering,fuel%20manufactured%20by%20BWX%20Technologies https://en.wikipedia.org/wiki/Virginia-class_submarine#:~:te....
connicpu 3y ago
Don't forget about nuclear submarines, those are quite a bit smaller e.g. the S6G model at around 165MW thermal with two 26MW steam turbines
deleted 3y ago
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mike_d 3y ago
> Small reactors won't be economical if they take that many people to run. The military has demonstrated you can easily maintain and operate them with a handful of 18 to 22 year olds.
- dragonwriter 3y ago
  > The military has demonstrated you can easily maintain and operate them with a handful of 18 to 22 year olds. No, they haven’t. Military reactors aren’t run by relatively junior enlisted personnel alone.
  - connicpu 3y ago
    Indeed, the navy sent my dad to go get his PhD before they had him as an engineering officer on a nuclear submarine. Sure some young enlisted might do some of the physical labor, but they're being supervised by someone who knows what they're doing.

adolph 3y ago

> Small reactors won't be economical if they take that many people to run. What are the numbers? What’s the TCO difference to similar systems without atmospheric carbon emissions?

kibwen 3y ago
The US Navy doesn't use nuclear reactors because of economics (they're quite expensive) or environmental concern. They use nukes because of the operational advantages of having a ship that only needs refueling once per decade. Any comparison to the naval use case is mostly useless when it comes to commercial power production.
- Alupis 3y ago
  *Once per ~30 years[1], to be pedantic. The reasons are not simply refueling concerns, although that is a factor. The boats still need to refuel the humans onboard, ie. food supplies and occasionally munitions. The reactor powers the boat using less mass than a typical diesel-electric, is more quiet, and can remain underwater for an entire deployment if necessary - something that's simply not possible with other power generation methods. [1] https://en.wikipedia.org/wiki/Virginia-class_submarine#:~:text=Specifications,-Lead%20boat%20Virginia&text=Propulsion%3A%20S9G%20nuclear%20reactor%20delivering,fuel%20manufactured%20by%20BWX%20Technologies https://en.wikipedia.org/wiki/Virginia-class_submarine#:~:te....
  - krisoft 3y ago
    > and can remain underwater for an entire deployment if necessary To be absolutely pedantic not all US navy reactors are on submarines. They also power surface ships with them.
- adolph 3y ago
  The claim is “Small reactors won't be economical if they take that many people [as the US Navy] to run.” The question is “What are the numbers?” Clearly the navy uses nukes due to advantageous performance characteristics. What are the numbers that a civilian small nuke must make to be viable?
  - nukeman 3y ago
    Quantity. One of the big issues with nuclear power is that we aren’t building frequently enough, and therefore lose expertise and capability, which drives up costs, both from screw-ups and from not being able to amortize over a large production run. To give an analogy, imagine if Boeing only made one 737 every five years. That aircraft would be insanely expensive. Personally, I’m bullish on the companies in the micro reactor space that have minimal site construction. I’m less bullish on Oklo, given that their application had some glaring omissions and got denied an NRC license.

Alupis 3y ago

> Also, naval reactors aren't small. Aircraft carriers have two 250 MW (700 MW thermal) reactors. Everything is relative - but there's vastly more nuclear powered submarines than aircraft carriers. The Virginia Class, for example, is powered by a single 30MW reactor[1]. The article states these "microreactors" will range from 15MW to 100MW. The "Nukes" in the Navy are highly trained, yes, but a military environment is going to be far rougher than anything privately managed for land-side power generation. [1] https://en.wikipedia.org/wiki/Virginia-class_submarine#:~:text=Specifications,-Lead%20boat%20Virginia&text=Propulsion%3A%20S9G%20nuclear%20reactor%20delivering,fuel%20manufactured%20by%20BWX%20Technologies https://en.wikipedia.org/wiki/Virginia-class_submarine#:~:te....

connicpu 3y ago

Don't forget about nuclear submarines, those are quite a bit smaller e.g. the S6G model at around 165MW thermal with two 26MW steam turbines

deleted 3y ago

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mike_d 3y ago

> Small reactors won't be economical if they take that many people to run. The military has demonstrated you can easily maintain and operate them with a handful of 18 to 22 year olds.

dragonwriter 3y ago
> The military has demonstrated you can easily maintain and operate them with a handful of 18 to 22 year olds. No, they haven’t. Military reactors aren’t run by relatively junior enlisted personnel alone.
- connicpu 3y ago
  Indeed, the navy sent my dad to go get his PhD before they had him as an engineering officer on a nuclear submarine. Sure some young enlisted might do some of the physical labor, but they're being supervised by someone who knows what they're doing.