7 ms·

I would say it must be a cost issue. The US Navy now has 65 years of experience running portable, robust, self-contained nuclear reactors, yet because of cost

by JackFr 5y ago

I would say it must be a cost issue. The US Navy now has 65 years of experience running portable, robust, self-contained nuclear reactors, yet because of cost (and presumably safety) they only put them in submarines and aircraft carriers, where there are compelling use cases that can't be satisfied by fossil fuel power plants.

devoutsalsa 5y ago
We can build small reactors if we really want them. Here’s a recent by the Illinois Energy Prof explaining one such case: “SMR - Small Module Nuclear Reactors — Gas Cooled” => https://youtu.be/TYnqJ4VnRM8 https://youtu.be/TYnqJ4VnRM8
- Animats 5y ago
  Hopefully better than last time. - Fort St. Vrain, US[1]. High temperature gas cooled reactor. Operated for 12 years. Corrosion problems. Converted to natural gas. - AVR reactor, Germany.[2] Pebble bed reactor. Had a pebble jam. Not repairable. Most fuel removed. Pressure vessel remains on site, with hope of full decommissioning in a century or so. There's a small reactor of this design working at a university in China, and a medium sized one one (200MW electrical output) is supposed to come on line this year. We'll see how that works out. Boring old boiling water and pressurized water reactors have simplicity in the radioactive part, and water is easy to handle. Designs that involve moving pellets or chemical processing of radioactive fluids add much complexity to a system that is very hard if not impossible to repair. The track record of such reactors is not good. [1] https://en.wikipedia.org/wiki/Fort_St._Vrain_Generating_Station https://en.wikipedia.org/wiki/Fort_St._Vrain_Generating_Stat... [2] https://en.wikipedia.org/wiki/AVR_reactor https://en.wikipedia.org/wiki/AVR_reactor
  - p_l 5y ago
    Boring old water cooled reactors (both boiling and pressured) are comparatively dangerous compared to quite well tested lead-bismuth cooled small modular reactors, which not only loadable on train car as self-contained part that needs no internal access, but are self-sealing in case of failure. Of course it's not as exotic as pebble bed reactor, or helium-cooled uranium-thorium reactor.
xoa 5y ago
For the USN (and other military's) ones at least there are many other differing issues and design goals that are divergent enough from civilian usage that it's definitely more then just cost. For example on the most basic issue of fuel, the A4W reactors (found on current USN super carriers) run on highly enriched U235, designed around 93% and as high as 97%. In other words, the fuel is flat out weapons grade by itself. A typical civilian plant is more like 3-5%. Very high enrichment allows more density and very long times between refueling, they can go something like 10 years vs 1-2 years for civilian. But obviously that would be a big proliferation concern even ignoring cost, nor are there many places to get that kind of fuel. For the military that is irrelevant, it's not a limiting problem since the vessels these reactors live on tend to also carry literal nuclear weapons. But it means it won't just transfer to other usage. There are plenty of other differences in naval reactors, like they also formulate with high burn up fuels (metal ceramics, u-al/u-zr) rather then uranium dioxide. Military vessels also have ample trained personnel to throw at maintenance and operations, they can make tradeoffs for things that are more finicky but provide higher performance. They're anything but "self-contained" really, and even the Navy wanted to simplify that. A major goal for the new A1B reactor in the Gerald R. Ford-class supercarriers, as well as normal stuff like "more power, weighs less" was to cut the number of people needed to run the reactors and propulsion. I mean, yeah, all this certainly does add to the cost too. But it's not just about the cost, or rather the design goals and missions are divergent enough that they necessitate costs for military reactors that would be a waste, dangerous, or both elsewhere. Where the Naval reactors might well carry over to I think would be future space usage, a lot of what the navy is worried about with sending a reactor out on a carrier or sub for years seems to overlap with challenges and goals faced by a reactor on a spaceship sent to the outer solar system.
- nickelpro 5y ago
  Can't put a traditional naval reactor or anything that resembles one on a spacecraft. 1) If it explodes on takeoff you're fucked 2) Naval reactors (and all reactors) require massive heatsinks to dissipate entropy. There's no ocean in space. Space-based nuclear energy is all based around RTGs, reactors have no place in space
  - 5y ago
briffle 5y ago
With an almost unlimited heat-sink available right next to the reactor, plus, nuclear technician training in the Navy is very, very difficult to pass.
- tbihl 5y ago
  >nuclear technician training in the Navy is very, very difficult to pass. Rigorous, yes, but not "very, very difficult to pass". The Navy needs a consistent stream of replacement operators, and their preferred way of getting them is to take reasonably capable volunteers and tutor/coach/remediate as many people as needed once they're in that group.
  - indymike 5y ago
    As someone who was a reactor opreator in the US Navy I'm laughing my ass off at this: "very, very difficult to pass". 90% of the people I started training with were gone in the first two years!
    - MurMan 5y ago
      > 90% of the people I started training with were gone in the first two years! My experience too. Do you remember the "skyhook"? We'd return to the barracks after class and find that the guy next to you had vanished without a trace.
merpnderp 5y ago
A lot of the cost is regulatory. Starting a project where 3/4ths of your time will be your construction crews idling while waiting on your army of lawyers to get injunctions lifted, makes the idea incredibly unattractive to investors. Which is the whole point of people who use the court system as a strategic barrier to new construction, even when they realize they'll likely ultimately lose.
njarboe 5y ago
The problem is that it is insanely costly and cumbersome to get regularly approval to build an experimental reactor in the US (and elsewhere I presume) so nuclear tech is stuck in the 1970's, just 20 years after the first commercial reactor was built. Imagine still using cars, or trains, or computers after only 20 years of development. One has to design the whole reactor on paper before building it and get it approved by the Nuclear Regulatory Commission (NRC). If, when you build it, you find you need to make changes to the design that are above a certain threshold, you have to recertify (not sure of the details. Can't find a good link about this). Imagine trying to build something as complicated as a nuclear reactor and you can't make iterative improvements. NuScales design approval process, the approval to be able to build the first reactor, cost $500 million dollars, took 2 million man hours, included over 2 million pages of documents, and after submitting in Jan of 2017 did not get approval until around 4 years later in August of 2020[1]. This is just to be able to build the first design. No wonder nuclear power has seen no progress in the last 50 years. Fortunately this company did persevere and now is planning to build the first power plant in Utah, hoping to be operational in 2030. The people/governments stating that climate change is a crisis, and I do believe there is way too much CO2 in the atmosphere, should be fast tracking this approved tech with as much money as usable to build thousands of these reactors as quickly as possible. [1]https://www.nuscalepower.com/technology/licensing https://www.nuscalepower.com/technology/licensing
- beisner 5y ago
  There should be pretty strict regulation for fission reactor development, simply because radioactive materials in runaway reactions can have totally uncontrollable, millennia-spanning consequences. Very few other technologies have this potential - even a regular chemical explosion poses little risk to future generations in a large radius. Certain materials (plutonium, for instance) can reach criticality very quickly and in tiny quantities, and plutonium is a byproduct of fission. (I’m not a nuclear physicist, so my understanding of the real potential here might be wrong, because I have no sense of the quantities that might be experienced). This isn’t a defense of the current regulatory process. The time frames, in particular, sound pretty egregious (4 years to approve a prototype, and 2m pages of documentation feels like a lot, too, but again I don’t know how these things are designed). But I would be extremely uncomfortable with lax regulatory oversight, given that nuclear accidents have permanent, irreversible impacts on society and geography. Now, small-scale reactors may be a different beast entirely. If the quantity of materials is pretty much guaranteed not to have potential to cause problems for anyone but the operators for a short period of time…. Then there certainly seems to be a case for a shorter regulatory cycle. But I would be shocked if scale isn’t already taken into account for the current regulatory burden.
duxup 5y ago
Nuclear powered submarine has a highly trained crew, many are busy monitoring / servicing the reactor. And the reactor brings itself home for service if needed. That seems way different than what you'd want in Antarctica.

by JackFr 5y ago

devoutsalsa 5y ago

We can build small reactors if we really want them. Here’s a recent by the Illinois Energy Prof explaining one such case: “SMR - Small Module Nuclear Reactors — Gas Cooled” => https://youtu.be/TYnqJ4VnRM8 https://youtu.be/TYnqJ4VnRM8

Animats 5y ago
Hopefully better than last time. - Fort St. Vrain, US[1]. High temperature gas cooled reactor. Operated for 12 years. Corrosion problems. Converted to natural gas. - AVR reactor, Germany.[2] Pebble bed reactor. Had a pebble jam. Not repairable. Most fuel removed. Pressure vessel remains on site, with hope of full decommissioning in a century or so. There's a small reactor of this design working at a university in China, and a medium sized one one (200MW electrical output) is supposed to come on line this year. We'll see how that works out. Boring old boiling water and pressurized water reactors have simplicity in the radioactive part, and water is easy to handle. Designs that involve moving pellets or chemical processing of radioactive fluids add much complexity to a system that is very hard if not impossible to repair. The track record of such reactors is not good. [1] https://en.wikipedia.org/wiki/Fort_St._Vrain_Generating_Station https://en.wikipedia.org/wiki/Fort_St._Vrain_Generating_Stat... [2] https://en.wikipedia.org/wiki/AVR_reactor https://en.wikipedia.org/wiki/AVR_reactor
- p_l 5y ago
  Boring old water cooled reactors (both boiling and pressured) are comparatively dangerous compared to quite well tested lead-bismuth cooled small modular reactors, which not only loadable on train car as self-contained part that needs no internal access, but are self-sealing in case of failure. Of course it's not as exotic as pebble bed reactor, or helium-cooled uranium-thorium reactor.

xoa 5y ago

For the USN (and other military's) ones at least there are many other differing issues and design goals that are divergent enough from civilian usage that it's definitely more then just cost. For example on the most basic issue of fuel, the A4W reactors (found on current USN super carriers) run on highly enriched U235, designed around 93% and as high as 97%. In other words, the fuel is flat out weapons grade by itself. A typical civilian plant is more like 3-5%. Very high enrichment allows more density and very long times between refueling, they can go something like 10 years vs 1-2 years for civilian. But obviously that would be a big proliferation concern even ignoring cost, nor are there many places to get that kind of fuel. For the military that is irrelevant, it's not a limiting problem since the vessels these reactors live on tend to also carry literal nuclear weapons. But it means it won't just transfer to other usage. There are plenty of other differences in naval reactors, like they also formulate with high burn up fuels (metal ceramics, u-al/u-zr) rather then uranium dioxide. Military vessels also have ample trained personnel to throw at maintenance and operations, they can make tradeoffs for things that are more finicky but provide higher performance. They're anything but "self-contained" really, and even the Navy wanted to simplify that. A major goal for the new A1B reactor in the Gerald R. Ford-class supercarriers, as well as normal stuff like "more power, weighs less" was to cut the number of people needed to run the reactors and propulsion. I mean, yeah, all this certainly does add to the cost too. But it's not just about the cost, or rather the design goals and missions are divergent enough that they necessitate costs for military reactors that would be a waste, dangerous, or both elsewhere. Where the Naval reactors might well carry over to I think would be future space usage, a lot of what the navy is worried about with sending a reactor out on a carrier or sub for years seems to overlap with challenges and goals faced by a reactor on a spaceship sent to the outer solar system.

nickelpro 5y ago
Can't put a traditional naval reactor or anything that resembles one on a spacecraft. 1) If it explodes on takeoff you're fucked 2) Naval reactors (and all reactors) require massive heatsinks to dissipate entropy. There's no ocean in space. Space-based nuclear energy is all based around RTGs, reactors have no place in space
- 5y ago

briffle 5y ago

With an almost unlimited heat-sink available right next to the reactor, plus, nuclear technician training in the Navy is very, very difficult to pass.

tbihl 5y ago
>nuclear technician training in the Navy is very, very difficult to pass. Rigorous, yes, but not "very, very difficult to pass". The Navy needs a consistent stream of replacement operators, and their preferred way of getting them is to take reasonably capable volunteers and tutor/coach/remediate as many people as needed once they're in that group.
- indymike 5y ago
  As someone who was a reactor opreator in the US Navy I'm laughing my ass off at this: "very, very difficult to pass". 90% of the people I started training with were gone in the first two years!
  - MurMan 5y ago
    > 90% of the people I started training with were gone in the first two years! My experience too. Do you remember the "skyhook"? We'd return to the barracks after class and find that the guy next to you had vanished without a trace.

merpnderp 5y ago

A lot of the cost is regulatory. Starting a project where 3/4ths of your time will be your construction crews idling while waiting on your army of lawyers to get injunctions lifted, makes the idea incredibly unattractive to investors. Which is the whole point of people who use the court system as a strategic barrier to new construction, even when they realize they'll likely ultimately lose.

njarboe 5y ago

The problem is that it is insanely costly and cumbersome to get regularly approval to build an experimental reactor in the US (and elsewhere I presume) so nuclear tech is stuck in the 1970's, just 20 years after the first commercial reactor was built. Imagine still using cars, or trains, or computers after only 20 years of development. One has to design the whole reactor on paper before building it and get it approved by the Nuclear Regulatory Commission (NRC). If, when you build it, you find you need to make changes to the design that are above a certain threshold, you have to recertify (not sure of the details. Can't find a good link about this). Imagine trying to build something as complicated as a nuclear reactor and you can't make iterative improvements. NuScales design approval process, the approval to be able to build the first reactor, cost $500 million dollars, took 2 million man hours, included over 2 million pages of documents, and after submitting in Jan of 2017 did not get approval until around 4 years later in August of 2020[1]. This is just to be able to build the first design. No wonder nuclear power has seen no progress in the last 50 years. Fortunately this company did persevere and now is planning to build the first power plant in Utah, hoping to be operational in 2030. The people/governments stating that climate change is a crisis, and I do believe there is way too much CO2 in the atmosphere, should be fast tracking this approved tech with as much money as usable to build thousands of these reactors as quickly as possible. [1]https://www.nuscalepower.com/technology/licensing https://www.nuscalepower.com/technology/licensing

beisner 5y ago
There should be pretty strict regulation for fission reactor development, simply because radioactive materials in runaway reactions can have totally uncontrollable, millennia-spanning consequences. Very few other technologies have this potential - even a regular chemical explosion poses little risk to future generations in a large radius. Certain materials (plutonium, for instance) can reach criticality very quickly and in tiny quantities, and plutonium is a byproduct of fission. (I’m not a nuclear physicist, so my understanding of the real potential here might be wrong, because I have no sense of the quantities that might be experienced). This isn’t a defense of the current regulatory process. The time frames, in particular, sound pretty egregious (4 years to approve a prototype, and 2m pages of documentation feels like a lot, too, but again I don’t know how these things are designed). But I would be extremely uncomfortable with lax regulatory oversight, given that nuclear accidents have permanent, irreversible impacts on society and geography. Now, small-scale reactors may be a different beast entirely. If the quantity of materials is pretty much guaranteed not to have potential to cause problems for anyone but the operators for a short period of time…. Then there certainly seems to be a case for a shorter regulatory cycle. But I would be shocked if scale isn’t already taken into account for the current regulatory burden.

duxup 5y ago

Nuclear powered submarine has a highly trained crew, many are busy monitoring / servicing the reactor. And the reactor brings itself home for service if needed. That seems way different than what you'd want in Antarctica.