Advanced Nuclear Reactors

I don't get the "revolutionizing power generation" part of the narrative. It's still a steam engine. It's still getting heat from the radioactive decay of uranium isotopes. It's not like whole-ass countries haven't ever generated a substantial portion of their base load with nuclear power. There's still all the same challenges of mining, containment, and waste. This isn't a revolution. It's an iteration.
 
The Great Zaganza said:
https://energy.stanford.edu/news/sm...es-highly-radioactive-nuclear-waste-new-study
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Says:
"produces radioactive waste that must be isolated from the environment for hundreds of thousands of years"
Which is wrong.

Most nuclear waste produced is hazardous, due to its radioactivity, for only a few tens of years and is routinely disposed of in near-surface disposal facilities (see above). Only a small volume of nuclear waste (~3% of the total) is long-lived and highly radioactive and requires isolation from the environment for many thousands of years.
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https://world-nuclear.org/informati...-waste/radioactive-wastes-myths-and-realities
But even this is the worst case scenario. If we reprocessed the fuel, it would return to the level of the original ore in a few hundred years. And would make the easily accessible ore last longer.
 
theprestige said:
I don't get the "revolutionizing power generation" part of the narrative. It's still a steam engine. It's still getting heat from the radioactive decay of uranium isotopes. It's not like whole-ass countries haven't ever generated a substantial portion of their base load with nuclear power. There's still all the same challenges of mining, containment, and waste. This isn't a revolution. It's an iteration.
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But if you add revolutionizing to the title, it gets more clicks.
 
crescent said:
Molten sodium isn't limited to nuclear power. The big solar-thermal sites west of Las Vegas also use them so that they can continue to generate power when power demand peaks in the evening. Realistically, anything that generate electricity could use that electricity to heat up that sodium, like a different sort of battery.
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Molten salts are used as storing medium, not raw sodium.
Sodium in this reactor is used in primary circuit. For primary circuit it's main advantage over water is that it has high boil temperature, and thus the primary circuit can be at low pressure.
It also has tons of disadvantages too, namely it's volatile AF.
It has no useful property for energy storage. I don't see how it would be useful for solar.
 
Dr.Sid said:
Molten salts are used as storing medium, not raw sodium.
Sodium in this reactor is used in primary circuit. For primary circuit it's main advantage over water is that it has high boil temperature, and thus the primary circuit can be at low pressure.
It also has tons of disadvantages too, namely it's volatile AF.
It has no useful property for energy storage. I don't see how it would be useful for solar.
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You are right, I should used the word "salt" instead of "sodium". But the point otherwise stands, molten salt heat storage is not limited to nuclear.
 
pipelineaudio said:
"nuclear waste" is a political term from Jimmy Carter, not a scientific one. Its also not really about the environment but to keep from weapons proliferation.

The scientific name for "nuclear waste" is "fuel" and should be used as such
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No.

Equipment and apparatus get irradiated over time, and can themselves become radioactive. Often this is above the natural background radiation, but well below the safety threshold for brief exposure. However, the effect can be cumulative. It becomes an issue for people who work with nuclear reactors, and can be exposed to many "safe" sources of radiation over the course of their career. If care is not taken, the cumulative effect can be carcinogenic, etc.

It's also why X-ray technicians wear shielding, even though a single round of X-rays is safe for the patient. Because the tech is exposed to a lot more doses over a lot shorter time period.

So. Irradiated equipment is (low-level) waste that still has to be stored somewhere nobody will be exposed to it until it cools down. Protective suits, tools, machinery, etc. Likewise reactor components that are being replaced. And perhaps the tools and equipment used in the replacement process. This can all be radioactive waste. Most of it is not very harmful if you happen to walk by it one day and then never again. But it's not the kind of thing you want to bury in someone's back yard, or over their water table, or in the nearest landfill.
 
theprestige said:
I don't get the "revolutionizing power generation" part of the narrative. It's still a steam engine. It's still getting heat from the radioactive decay of uranium isotopes. It's not like whole-ass countries haven't ever generated a substantial portion of their base load with nuclear power. There's still all the same challenges of mining, containment, and waste. This isn't a revolution. It's an iteration.
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Distribution of electricity generation in the Canadian province of Ontario as of July 2023, by source

It's 58 per cent.

Construction of new ones is underway:

Ontario plans massive expansion in nuclear power

These will work when the rivers don't flow, the sun doesn't shine and the winds don't blow.
 
theprestige said:
Equipment and apparatus get irradiated over time, and can themselves become radioactive. Often this is above the natural background radiation, but well below the safety threshold for brief exposure. However, the effect can be cumulative. It becomes an issue for people who work with nuclear reactors, and can be exposed to many "safe" sources of radiation over the course of their career. If care is not taken, the cumulative effect can be carcinogenic, etc.
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Sure, but there's a whole lot of conflating of different sorts of radioactive waste together as if it were all the same, and it's not. For example, the linked Stanford article says,

“Our results show that most small modular reactor designs will actually increase the volume of nuclear waste in need of management and disposal, by factors of 2 to 30 for the reactors in our case study,”​

Volume is an absolute **** metric for nuclear waste. I don't care about volume. What matters is what kind of waste you've got, how long it lasts, and how radioactive it is. If it's short-term waste, the volume really isn't a problem. And most radioactive waste (measured by volume) is short term waste.

The really long term stuff, the stuff that won't stop being radioactive for thousands or even millions of years if left alone, is mostly the spent fuel. And pipeline is right about that: spent fuel is still fuel, it just needs to be reprocessed. Reprocessing takes most of that really radioactive stuff and puts it back in the reactor to be burned up.

So. Irradiated equipment is (low-level) waste that still has to be stored somewhere nobody will be exposed to it until it cools down.
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Absolutely. But we've already solved that problem. You put it in shielded safe storage for a few decades, and you're done, it's no longer dangerous, and it then can go into the nearest landfill. Having a reactor which produces more short term waste isn't really an issue.

Even the spent fuel disposal has been technically solved, it's only politics keeping us from a "permanent" solution.
 
theprestige said:
I don't get the "revolutionizing power generation" part of the narrative. It's still a steam engine. It's still getting heat from the radioactive decay of uranium isotopes. It's not like whole-ass countries haven't ever generated a substantial portion of their base load with nuclear power. There's still all the same challenges of mining, containment, and waste. This isn't a revolution. It's an iteration.
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The diesel engine works the same way a coal-fired steam engine works. You're still burning fuel to heat a gas which expands a piston to rotate a shaft. And yet, diesel engines are vastly superior to coal-fired steam engines. The difference is important.

SMRs offer some major practical advantages over traditional nuclear reactors. In particular, the problem of cooling is made much, much easier. Look at most power reactors in the USA today, and you'll notice a pattern: they're basically all built next to either the ocean or a river. Why? Because they need a **** ton of water for cooling. They need so much water that they cannot get by with municipal water supply, they cannot get by with water tanks, they cannot get by with mere pipes. And because they need to be positioned either on the coast or on a river, that massively restricts where these things are built. And location is a HUGE factor in how or even whether a reactor gets built. That's in large part a political problem, but it's still a huge problem.

SMRs offer a technical solution to that political problem of where to build the reactor, because they don't need to be built next to a major river or on the coast. You can build them just about anywhere. And so it's going to be vastly easier to find locations for them that are acceptable.
 
Dr.Sid said:
Molten salts are used as storing medium, not raw sodium.

Sodium in this reactor is used in primary circuit. For primary circuit it's main advantage over water is that it has high boil temperature, and thus the primary circuit can be at low pressure.

It also has tons of disadvantages too, namely it's volatile AF.

It has no useful property for energy storage. I don't see how it would be useful for solar.
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My experience of salt is that it's highly corrosive.

Sabine talks about the thermal properties of molten salt that make it useful for storing heat.
 
Gord_in_Toronto said:
Distribution of electricity generation in the Canadian province of Ontario as of July 2023, by source

It's 58 per cent.

Construction of new ones is underway:

Ontario plans massive expansion in nuclear power

These will work when the rivers don't flow, the sun doesn't shine and the winds don't blow.
Click to expand...

No, they won't work when the rivers don't flow - when the source for cooling gets too low or too warm, reactors have to shut down, a frequent problem for many reactors in Europe and elsewhere.
It is just not true that nuclear power isn't affected by global warming.
 
The Great Zaganza said:
https://energy.stanford.edu/news/sm...es-highly-radioactive-nuclear-waste-new-study

original article:
https://www.pnas.org/doi/full/10.1073/pnas.2111833119
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Hardly surprising. SMR proponents don't do these studies because they don't want to know. They don't want us to know either, else we might not be so enthusiastic about them.

In the case of sodium- and molten salt–cooled SMRs, the primary coolant will be chemically reactive, heated to temperatures >500 °C, and highly radioactive. Under these extreme conditions, reactor components can have a shorter lifetime than the standard PWR (60 y), and this will increase decommissioning LILW volumes. In addition, nonlight water SMRs will introduce uncommon types of LILW in the form of neutron reflectors and chemically reactive coolant or moderator materials...

Molten salt reactor vessel lifetimes will be limited by the corrosive, high-temperature, and radioactive in-core environment. In particular, the chromium content of 316-type stainless steel that constitutes a PWR pressure vessel is susceptible to corrosion in halide salts. Nevertheless, some developers, such as ThorCon, plan to adopt this stainless steel...

Terrestrial Energy may construct their 400-MWth IMSR vessel from Hastelloy N, a nickel-based alloy that has not been code certified for commercial nuclear applications by the American Society of Mechanical Engineers. Since this nickel-based alloy suffers from helium embrittlement, Terrestrial Energy envisions a 7-y lifetime for their reactor vessel. Molten salt reactor vessels will become contaminated by salt-insoluble fission products and will also become neutron-activated through exposure to a thermal neutron flux greater than 1012 neutrons/cm2-s. Thus, it is unlikely that a commercially viable decontamination process will enable the recycling of their alloy constituents...

Conclusions
This analysis of three distinct SMR designs shows that, relative to a gigawatt-scale PWR, these reactors will increase the energy-equivalent volumes of SNF, long-lived LILW, and short-lived LILW by factors of up to 5.5, 30, and 35, respectively. These findings stand in contrast to the waste reduction benefits that advocates have claimed for advanced nuclear technologies.
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Dealing with radioactive waste is a lot trickier than nuclear advocates would have you believe, and new types of reactor may introduce new types of waste requiring different disposal methods that are not well proven. A policy of 'Just get them running and worry about the waste later' is not acceptable. That's how we got into this current mess with fossil fuels.
 
I find it almost precocious how little concern proponents of more nuclear power have that we will deal with nuclear waste, given that we have not really found a way to deal with the waste we have already accumulated.

It's like saying that the next cats I adopt will be so much cleaner than the hundreds of cats that are already ******** and pissing all over my house.
 
theprestige said:
So. Irradiated equipment is (low-level) waste that still has to be stored somewhere nobody will be exposed to it until it cools down. Protective suits, tools, machinery, etc. Likewise reactor components that are being replaced. And perhaps the tools and equipment used in the replacement process. This can all be radioactive waste. Most of it is not very harmful if you happen to walk by it one day and then never again. But it's not the kind of thing you want to bury in someone's back yard, or over their water table, or in the nearest landfill.
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That's not what the media calls "nuclear waste". However, I do wonder, is this stuff also stored at places like Yucca mountain? You may have learned me something new
 
pipelineaudio said:
That's not what the media calls "nuclear waste". However, I do wonder, is this stuff also stored at places like Yucca mountain? You may have learned me something new
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I'm afraid that no nuclear waste is actually stored at Yucca mountain for political reasons.

https://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_repository

I think it's a shame myself, because it seems like a pretty good place to put it. But Nevadans seem to be up in arms about being the state where all the nuclear stuff goes, including the early bomb tests and everyone else's nuclear waste.
 
Puppycow said:
I'm afraid that no nuclear waste is actually stored at Yucca mountain for political reasons.



https://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_repository



I think it's a shame myself, because it seems like a pretty good place to put it. But Nevadans seem to be up in arms about being the state where all the nuclear stuff goes, including the early bomb tests and everyone else's nuclear waste.
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Australia has the same problem. You would think that with our much lower population density, there would be somewhere that would be the official nuclear waste dump. After many decades of the Government trying, that place has yet to be commissioned.
 
I'm a bit puzzled by this.

It seems obvious to me that the best way to deal with radioactive waste is to load it onto a decommissioned boat, tug it out to a deep part of the ocean and sink it.

What am I missing?
 
The Great Zaganza said:
I'm a bit puzzled by this.

It seems obvious to me that the best way to deal with radioactive waste is to load it onto a decommissioned boat, tug it out to a deep part of the ocean and sink it.

What am I missing?
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If the container leaks, then ocean water can spread the stuff around, which we don't want. And long term, ocean water isn't the best environment for making sure containers don't leak.
 
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