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This is not a very good idea for several reasons. Naval reactors require fuel that is much more enriched than normal reactors. They also produce significantly l

This is not a very good idea for several reasons. Naval reactors require fuel that is much more enriched than normal reactors. They also produce significantly lower electricity. The Palo Verde facility produces 3GW of electricity and cost $11B in 2019 dollars. Each of the A1B reactors generates 125 MW. Life span of the reactor is not specified, but it's predecessor the A4W had a 23 year life span. By comparison, new nuclear plants are slated to last 50-80 years. The net cost per GWh of electricity of the naval reactor is significantly worse than commercial plants. This is to be expected, because naval reactors are built to be compact and withstand the rocking of a ship at sea. Commercial reactors can leverage the efficiency of larger scale, and are built to be much more long lasting.

credit_guy 6y ago
An A1B generates 125 MW electricity, but also 260 MW of additional thermal power used to power the propellers. If you convert the latter one to electricity at a 45% efficiency (typical efficiency for a generation IV nuclear power plant steam turbine), you get 117 MW, for a total of 242 MW. Two reactors could produce then about 0.5 GW. At a $1 BN cost, that's $2 BN / GW. Palo Verde was brought online more than 30 years ago. If you look at Vogtle 3-4 (to be brought online in the next 2 years... if we are lucky) or Hinkley Point C, you'll see projected costs of respectively $25 BN for 2.5 GW and $32 BN for 3.2 GW. In both cases that comes at $10 BN/ GW. That is 5 times more expensive than the naval reactor. Now, as you said, the cost of a naval reactor is very likely inflated by the exacting demands of its military usage. It needs to be compact, to work on a rocking ship, presumably it needs to be able to survive a certain amount of abuse that's to be expected if a ship/boat actually participates in combat, and I'm sure there are 100 other things that I'm missing here. All these factors make military devices absurdly expensive compared to the same devices intended for civilian use. The logical conclusion is that if DoE wants to repurpose naval reactors for civilian use, then it can achieve significant cost savings. What I'm saying is that even not factoring these savings in, you still end up 5 times cheaper than the civilian reactors that are currently being built. Edit: The lifespan of a Gerald Ford-class carrier is expected to be 50 years. The Nimitz aircraft carrier was launched 49 years ago. They do not replace their reactors. So, a naval reactor is designed to work for at least 50 years.
- sir_bearington 6y ago
  You also need to build a secondary containment vessel for the reactor, which is a significant expense. Because the cost of this containment is a function of surface area and generating capacity is a function of volume it's better to increase size. You also need to build steam turbines, heat exchangers, transformers, etc. The cost of the reactor is only a portion of the cost of the whole nuclear plant. > Palo Verde was brought online more than 30 years ago. If you look at Vogtle 3-4 (to be brought online in the next 2 years... if we are lucky) or Hinkley Point C, you'll see projected costs of respectively $25 BN for 2.5 GW and $32 BN for 3.2 GW. In both cases that comes at $10 BN/ GW. That is 5 times more expensive than the naval reactor. And by comparison you have the Taishan plant built for $7.5B with 3.5 GW generating capacity. If we want to go around cherry-picking examples we can also cherry-pick the cheap plants. We have already tried using maritime nuclear reactors for grid generation. The first nuclear plants brought online for grid generation were maritime reactors repurposed for grid production. Larger purpose-built reactors won out.
  - epistasis 6y ago
    Vogtle and Hinckley aren't cherry picking expensive plants, it's cherry picking middle of the road. VC Summer is expensive, many billions spent and nothing to come of it ever. Where do your cost numbers from Taishan come from? How do you come to costs that are believable from massive Chinese construction, or at least a cost that might be transferable at all to the rest of the world? The history of nuclear is very clear: keep on increasing costs throughout construction, just enough that, taking into account the sunk cost fallacy, it makes sense to soldier on. VC Summer overshot that, and had massive corruption in the auditing of all parts of the project. Somehow Vogtle continues. We literally do not know how to build nuclear in a cost effective manner any more. We can't structure contracts in the right way, we can't perform engineering to a high enough degree to make constructive plans. At Vogtle they literally poured the wrong concrete, and had to go back and get the design recertified with the NRC, because the original design was impossible to build, and on site they just plowed ahead with what they thought they could build. This is the level of incompetence, ball dropping, and bad contract structure. Perhaps this sort of thing is fixable, but not on any reasonable timeline. The management is rotten from the top, so there's nobody that we can even order a nuclear reactor from. Suppose you had $7.5B and wanted 3GW of nuclear at one of the many sites in the US that would welcome nuclear and its jobs. Who do you even bring that money to in order to build it? Rosatom? Are they going to meet NRC standards?
bob29 6y ago
Great by the same logic you should use a commercial reactor over a naval reactor, you should also just use a different power source over nuclear.
- sir_bearington 6y ago
  What other power source generates carbon-free energy without intermittency or geographic dependency?
  - bob29 6y ago
    So you can build nuclear in a tsunami zone? in a seismic zone? in an area without cooling? So you can mine and enrich uranium without carbon? Nuclear does none of the things you fantasize it to do really.
    - sir_bearington 6y ago
      > So you can build nuclear in a tsunami zone? in a seismic zone? in an area without cooling? Yes, you harden the structure against tsunamis and earthquakes. That's part of why nuclear plants are so expensive. Atmospheric cooling can indeed be done anywhere. It's typically easier and more efficient to use water cooling. And humans need water to survive, and thus population centers are built near sources of water, water cooling is almost always an option. Also nuclear plants can be cooled with seawater. This is in stark contrast to hydroelectricity which needs both a river and a valley to be viable. Geothermal power needs magma near enough to the surface to heat water into steam. > So you can mine and enrich uranium without carbon? I don't see why not. Use electricity produced by nuclear plants to drive centrifuges. Also use said electricity to power mining equipment. And you didn't answer my question: What other carbon-free sources provide energy 24/7, besides ones that need very specific geography like hydroelectricity and geothermal power?
      - bob29 6y ago
        Easy, there’s many: 1) Solar + transmission lines. It’s always sunny somewhere 2) wind + transmission lines, always windy somewhere 3) use some energy produced by hydro to manufacture some concrete river beds and reservoirs 4) use some of the energy produced by 1-3 to dig real deep for geothermal everywhere 5) Ocean thermal energy conversion Don’t get me wrong , I’m not anti nuclear , I’m a huge fan of the big reactor in the sky it produces all we need with perfect reliability there’s no reason to do something as dumb as trying to build terrestrial reactors

credit_guy 6y ago

An A1B generates 125 MW electricity, but also 260 MW of additional thermal power used to power the propellers. If you convert the latter one to electricity at a 45% efficiency (typical efficiency for a generation IV nuclear power plant steam turbine), you get 117 MW, for a total of 242 MW. Two reactors could produce then about 0.5 GW. At a $1 BN cost, that's $2 BN / GW. Palo Verde was brought online more than 30 years ago. If you look at Vogtle 3-4 (to be brought online in the next 2 years... if we are lucky) or Hinkley Point C, you'll see projected costs of respectively $25 BN for 2.5 GW and $32 BN for 3.2 GW. In both cases that comes at $10 BN/ GW. That is 5 times more expensive than the naval reactor. Now, as you said, the cost of a naval reactor is very likely inflated by the exacting demands of its military usage. It needs to be compact, to work on a rocking ship, presumably it needs to be able to survive a certain amount of abuse that's to be expected if a ship/boat actually participates in combat, and I'm sure there are 100 other things that I'm missing here. All these factors make military devices absurdly expensive compared to the same devices intended for civilian use. The logical conclusion is that if DoE wants to repurpose naval reactors for civilian use, then it can achieve significant cost savings. What I'm saying is that even not factoring these savings in, you still end up 5 times cheaper than the civilian reactors that are currently being built. Edit: The lifespan of a Gerald Ford-class carrier is expected to be 50 years. The Nimitz aircraft carrier was launched 49 years ago. They do not replace their reactors. So, a naval reactor is designed to work for at least 50 years.

sir_bearington 6y ago
You also need to build a secondary containment vessel for the reactor, which is a significant expense. Because the cost of this containment is a function of surface area and generating capacity is a function of volume it's better to increase size. You also need to build steam turbines, heat exchangers, transformers, etc. The cost of the reactor is only a portion of the cost of the whole nuclear plant. > Palo Verde was brought online more than 30 years ago. If you look at Vogtle 3-4 (to be brought online in the next 2 years... if we are lucky) or Hinkley Point C, you'll see projected costs of respectively $25 BN for 2.5 GW and $32 BN for 3.2 GW. In both cases that comes at $10 BN/ GW. That is 5 times more expensive than the naval reactor. And by comparison you have the Taishan plant built for $7.5B with 3.5 GW generating capacity. If we want to go around cherry-picking examples we can also cherry-pick the cheap plants. We have already tried using maritime nuclear reactors for grid generation. The first nuclear plants brought online for grid generation were maritime reactors repurposed for grid production. Larger purpose-built reactors won out.
- epistasis 6y ago
  Vogtle and Hinckley aren't cherry picking expensive plants, it's cherry picking middle of the road. VC Summer is expensive, many billions spent and nothing to come of it ever. Where do your cost numbers from Taishan come from? How do you come to costs that are believable from massive Chinese construction, or at least a cost that might be transferable at all to the rest of the world? The history of nuclear is very clear: keep on increasing costs throughout construction, just enough that, taking into account the sunk cost fallacy, it makes sense to soldier on. VC Summer overshot that, and had massive corruption in the auditing of all parts of the project. Somehow Vogtle continues. We literally do not know how to build nuclear in a cost effective manner any more. We can't structure contracts in the right way, we can't perform engineering to a high enough degree to make constructive plans. At Vogtle they literally poured the wrong concrete, and had to go back and get the design recertified with the NRC, because the original design was impossible to build, and on site they just plowed ahead with what they thought they could build. This is the level of incompetence, ball dropping, and bad contract structure. Perhaps this sort of thing is fixable, but not on any reasonable timeline. The management is rotten from the top, so there's nobody that we can even order a nuclear reactor from. Suppose you had $7.5B and wanted 3GW of nuclear at one of the many sites in the US that would welcome nuclear and its jobs. Who do you even bring that money to in order to build it? Rosatom? Are they going to meet NRC standards?

bob29 6y ago

Great by the same logic you should use a commercial reactor over a naval reactor, you should also just use a different power source over nuclear.

sir_bearington 6y ago
What other power source generates carbon-free energy without intermittency or geographic dependency?
- bob29 6y ago
  So you can build nuclear in a tsunami zone? in a seismic zone? in an area without cooling? So you can mine and enrich uranium without carbon? Nuclear does none of the things you fantasize it to do really.
  - sir_bearington 6y ago
    > So you can build nuclear in a tsunami zone? in a seismic zone? in an area without cooling? Yes, you harden the structure against tsunamis and earthquakes. That's part of why nuclear plants are so expensive. Atmospheric cooling can indeed be done anywhere. It's typically easier and more efficient to use water cooling. And humans need water to survive, and thus population centers are built near sources of water, water cooling is almost always an option. Also nuclear plants can be cooled with seawater. This is in stark contrast to hydroelectricity which needs both a river and a valley to be viable. Geothermal power needs magma near enough to the surface to heat water into steam. > So you can mine and enrich uranium without carbon? I don't see why not. Use electricity produced by nuclear plants to drive centrifuges. Also use said electricity to power mining equipment. And you didn't answer my question: What other carbon-free sources provide energy 24/7, besides ones that need very specific geography like hydroelectricity and geothermal power?
    - bob29 6y ago
      Easy, there’s many: 1) Solar + transmission lines. It’s always sunny somewhere 2) wind + transmission lines, always windy somewhere 3) use some energy produced by hydro to manufacture some concrete river beds and reservoirs 4) use some of the energy produced by 1-3 to dig real deep for geothermal everywhere 5) Ocean thermal energy conversion Don’t get me wrong , I’m not anti nuclear , I’m a huge fan of the big reactor in the sky it produces all we need with perfect reliability there’s no reason to do something as dumb as trying to build terrestrial reactors