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Why don't they build sites with many small productised nuclear sub propulsion type reactors, as opposed to a single monstrous and pretty much bespoke reactor? I

Why don't they build sites with many small productised nuclear sub propulsion type reactors, as opposed to a single monstrous and pretty much bespoke reactor? I'm sure there's a good reason but on the surface it seems like commodity reactors would be a far cheaper approach in the end.

yourapostasy 8y ago
> ...commodity reactors would be a far cheaper approach in the end. I've read claims that in the US, unfortunately there are no commodity reactors, with commensurately commodity costs in licensing, environmental and regulatory approvals. Each reactor is effectively a one-off effort, with a minority of transferable capital equipment, skills, etc. I've also read that France's reactors are far more uniform, and they reap many benefits from it. I wish more research and engineering could be justified into ultra-small reactors like described in this Quora response [1]. Not really sure what he meant by a magneto-hydrodynamic power conversion because I didn't picture a conductive fluid involved from his description, but I wonder if the reaction can be scaled down even smaller than the proposed 100 GJ burst (I somehow suspect battery chemistries don't take kindly to those scales of bursts). [1] https://www.quora.com/Is-there-a-micro-nuclear-reactor-that-can-power-up-a-house-for-entire-life-time https://www.quora.com/Is-there-a-micro-nuclear-reactor-that-...
- greglindahl 8y ago
  The whole point of the new generation of both Westinghouse and EDF reactors is that each would be a commodity. And both are stumbling at the start.
brandmeyer 8y ago
Because there are natural economies of scale in building larger nuclear reactors. Submarine propulsion reactors are several times more expensive than commercial reactors on a per-unit-power basis, even after accounting for the overruns.
- growlist 8y ago
  I was being lazy in my post I suppose: work on this idea is well underway. Whether it proves successful or not still seems unclear: https://en.wikipedia.org/wiki/Small_modular_reactor https://en.wikipedia.org/wiki/Small_modular_reactor
  - brandmeyer 8y ago
    The wikipedia article doesn't do a good job of selling it. Lets take a statement like this: "Nuclear reactor fuel can be low-enriched uranium, with a concentration of less than 20% of fissile 235 U. This low quantity, non-weapons-grade uranium makes the fuel less desirable for weapons production." 20% enrichment is far higher than what is typically used in commercial power reactors. Because of the exponential behavior of uranium enrichment, 20% is almost all the way up to weapon's-grade material. Its part of why Iran's stockpile of 20-40% material was so concerning - they could have very quickly converted that into bombs. If you have the technology to crank out 20% U-235 in quantity, then you also have the technology to make weapons in quantity. Here's another concerning statement, "Many SMRs are fast reactors..." Fast reactors are inherently capable of being used for mass-production of plutonium. Plutonium production from fast breeder reactors is far less expensive than uranium enrichment, and an even higher proliferation risk. Honestly, I think that the only reason small modular reactors have some traction because they appear to require less capital investment than full-scale reactors, thus drawing VC slush money.
- Reason077 8y ago
  The large size of nuclear reactors is often one of the factors blamed for their high cost. Small Modular Reactors (SMRs), which could be manufactured in factories rather than in bespoke, on-site builds, are regarded as a technology that could bring down the cost of nuclear builds in future. I suspect submarine reactors are expensive because of their unique design constraints, relatively small production runs, and the fact that they are contracted/built on military budgets rather than in competitive commercial environments.

yourapostasy 8y ago

> ...commodity reactors would be a far cheaper approach in the end. I've read claims that in the US, unfortunately there are no commodity reactors, with commensurately commodity costs in licensing, environmental and regulatory approvals. Each reactor is effectively a one-off effort, with a minority of transferable capital equipment, skills, etc. I've also read that France's reactors are far more uniform, and they reap many benefits from it. I wish more research and engineering could be justified into ultra-small reactors like described in this Quora response [1]. Not really sure what he meant by a magneto-hydrodynamic power conversion because I didn't picture a conductive fluid involved from his description, but I wonder if the reaction can be scaled down even smaller than the proposed 100 GJ burst (I somehow suspect battery chemistries don't take kindly to those scales of bursts). [1] https://www.quora.com/Is-there-a-micro-nuclear-reactor-that-can-power-up-a-house-for-entire-life-time https://www.quora.com/Is-there-a-micro-nuclear-reactor-that-...

greglindahl 8y ago
The whole point of the new generation of both Westinghouse and EDF reactors is that each would be a commodity. And both are stumbling at the start.

brandmeyer 8y ago

Because there are natural economies of scale in building larger nuclear reactors. Submarine propulsion reactors are several times more expensive than commercial reactors on a per-unit-power basis, even after accounting for the overruns.

growlist 8y ago
I was being lazy in my post I suppose: work on this idea is well underway. Whether it proves successful or not still seems unclear: https://en.wikipedia.org/wiki/Small_modular_reactor https://en.wikipedia.org/wiki/Small_modular_reactor
- brandmeyer 8y ago
  The wikipedia article doesn't do a good job of selling it. Lets take a statement like this: "Nuclear reactor fuel can be low-enriched uranium, with a concentration of less than 20% of fissile 235 U. This low quantity, non-weapons-grade uranium makes the fuel less desirable for weapons production." 20% enrichment is far higher than what is typically used in commercial power reactors. Because of the exponential behavior of uranium enrichment, 20% is almost all the way up to weapon's-grade material. Its part of why Iran's stockpile of 20-40% material was so concerning - they could have very quickly converted that into bombs. If you have the technology to crank out 20% U-235 in quantity, then you also have the technology to make weapons in quantity. Here's another concerning statement, "Many SMRs are fast reactors..." Fast reactors are inherently capable of being used for mass-production of plutonium. Plutonium production from fast breeder reactors is far less expensive than uranium enrichment, and an even higher proliferation risk. Honestly, I think that the only reason small modular reactors have some traction because they appear to require less capital investment than full-scale reactors, thus drawing VC slush money.
Reason077 8y ago
The large size of nuclear reactors is often one of the factors blamed for their high cost. Small Modular Reactors (SMRs), which could be manufactured in factories rather than in bespoke, on-site builds, are regarded as a technology that could bring down the cost of nuclear builds in future. I suspect submarine reactors are expensive because of their unique design constraints, relatively small production runs, and the fact that they are contracted/built on military budgets rather than in competitive commercial environments.