Skeptics and nuclear power

[Belz...]

Can you elaborate on this. It seems you just told me that a chain reaction is a chain reaction. How is that supposed to be helpful?

Well since you made a distinction between a chain reaction and a chain reaction, I saw it as important to note that a chain reaction is, in fact, the same thing as a chain reaction.

 

[bobdroege7]

The chain reaction doesn't depend on the turbines and the conditions required are not as precise as you seem to think.

That depends on the design of the reactor, naval submarine reactor power is controlled by the throttle valve on the turbines.

Opening the throttle pulls more steam out of the steam generator, which cools the steam generator, which cools the reactor coolant water flowing through it, making it more dense, thereby being a more effective moderator, which increases the amount of thermal neutrons in the core, which increases the reactor power level.

 

[RecoveringYuppy]

Simply have the technical ability to do a certain thing does not automatically mean that the thing in question should be actually be done.

How does that apply here?

The original claim was that there was "no solution in sight". That's simply wrong. There are solutions in actual operation and many others available.

 

[bobdroege7]

I was referring to the core, which didn't explode. There were other explosions in the faculty, so it I could have been cleaner.

It was a pressure excursion in the core, if you want to call that an explosion, I am ok with that. But since the fuel didn't explode, I am also ok with saying it was not a nuclear explosion.

To be accurate though, the chain reaction proceeded without having to wait for the neutrons that come from fission products. What is called a prompt critical chain reaction which means that the power level increased much faster than the plant was designed for.

To explain, some fission products decay by emitting a neutron, and there are half-lives with respect to each nuclide that emits neutrons, this is what allows for control of nuclear reactors.

 

[Roboramma]

This is simply a callback to previous project that extracted a small amount of uranium under laboratory conditions. This was 15 years ago and it’s no closer to commercial scale extraction. The cost estimate is at best thumb in the air speculation as neither they nor anyone else have proposed anything that even remotely resembles a commercial design.

They actually did it for $300/kg.

There's no reason to attempt to do this commercially now because that's 3 times the current price of mined uranium. But this is a proof of concept that shows it is certainly possible.

What do you think will prevent the same technique that they used to extract uranium from seawater from continuing to work at scale? One would generally expect large scale operations to achieve lower price/kg, not higher.

At what point do you think the price of Uranium would prevent nuclear power from being economical? $3000/kg? $30000/kg?

The uranium is demonstrably there. The uranium can be demonstrably extracted at a relatively low price, just not one competitive with mining at this point. But if you are suggesting that the mines will run out of uranium, as that happens the price will rise and this certainly will become competitive.

You don't get to ignore this source.

 

[Roboramma]

You think the uranium atoms broke? Fission and chain reactions are natural events for uranium. And there is no doubt that there is a very high concentration of uranium there and further that uranium is enriched in the isotopes that support chain reactions. There is also no doubt that some, possibly most, of the original moderator is still present (some of it burned away).

It's clear to me that you are right that the chain reaction should be happening at some rate. Each uranium atom has some chance of spontaneous fission /unit time. The presence of other uranium atoms in the vicinity also undergoing fission increases this rate by the process of free neutrons causing fission in nuclei that they run into, which means more fission, which means the rate is higher, etc.

My question is how much higher is the rate at Chernobyl now than the half-life of uranium without the chain reaction? If it's increasing the rate of fission by 50% that's pretty meaningful. If it's increasing the rate by 0.01% then it's not really worth talking about.

I have no idea, but rather than talking about whether or not it's happening at all (I agree with you that it must be), what seems to me to be meaningful is the degree to which the rate is affected by the chain reaction.

 

[Belz...]

My question is how much higher is the rate at Chernobyl now than the half-life of uranium without the chain reaction? If it's increasing the rate of fission by 50% that's pretty meaningful.

Not really, actually. The "natural" half-life of U-235 is pretty damn long. Cutting it by half still gives you pretty low radioactivity. And we're talking about alpha radiation. I suspect the situation at the reactor is a _lot_ worse than that.

 

[Dr.Sid]

Uranium is of least concern .. used (even slightly used) nuclear fuel is full of product of fission of different half-times .. yes, the worst isotopes are gone. But even so the fuel is highly radioactive, it will kill people after seconds of exposure.
Or look at hot spots in Fukushima .. they have problems building robots which would last 20 minutes in there ..

 

[Belz...]

Uranium is of least concern .. used (even slightly used) nuclear fuel is full of product of fission of different half-times .. yes, the worst isotopes are gone. But even so the fuel is highly radioactive

Yeah well I was only addressing the question of the uranium itself. Of course, the spent fuel products can be pretty dangerous, if only for a short while. The higher the radioactivity, the shorter the half-life.

it will kill people after seconds of exposure.

A clarification: after seconds of exposure to a few sieverts, the radiation will kill you, but only in a few weeks of horrible pain. You won't die in seconds.

Or look at hot spots in Fukushima .. they have problems building robots which would last 20 minutes in there ..

In most places it's microsieverts per hour. However, inside the reactor the radiation levels, even six years later, seem rather, ahem... extreme.

 

[Crossbow]

How does that apply here?

The original claim was that there was "no solution in sight". That's simply wrong. There are solutions in actual operation and many others available.

It is quite applicable because it is true.

If there actually is a good solution to the safe disposal of nuclear materials, then there should be quite possible to safely dispose of nuclear waste materials.

However, since there are considerable problems with the safe waste disposal of nuclear materials, then it is quite evident that it is not possible to safely dispose of nuclear waste materials.

If you can show a good solution for the safe disposal for nuclear materials, then I (and quite a few other people) would be most happy to support it. Also, if you do have such a solution, then I expect that you would soon be a very wealthy man.

However, at least here in the USA there is not any good solution for the safe disposal of nuclear materials even though the USA has spent billions of dollars over many decades in order to produce a good solution for the safe disposal of nuclear materials.

 

[The Great Zaganza]

Supposedly, the best system the US has come up with so far is to dig a deep hole in the desert, dump everything in and fill it up again.
See WIPP, New Mexico)

 

[lomiller]

They actually did it for $300/kg.

They produced 2 Kg of Uranium, total. The project cost a LOT more than $600.

 

[wobs]

Simply have the technical ability to do a certain thing does not automatically mean that the thing in question should be actually be done.

Because the moral thing to do with anything waste we create (nuclear or otherwise) is to manage responsibly.

In the case of spent nuclear fuel, the issue has been looked at by international multi-disciplinary teams for many years. We know how to dispose of spent fuel, and that is deep geological depository. That someone might not want to use Yucca mountain only means you either over ride that or come up with a better site.

Although one reason they don't want to use it is that much of the waste has yet to be reprocessed, which would give more energy, and leave less long-lived actinides. But in the end one would still need to dispose of it eventually, and this is the best, and safest way.

Some of it has already been vitrified, so this would probably be disposed of as is.

 

[Belz...]

They produced 2 Kg of Uranium, total. The project cost a LOT more than $600.

Are you including R&D costs in there?

 

[wobs]

However, since there are considerable problems with the safe waste disposal of nuclear materials, then it is quite evident that it is not possible to safely dispose of nuclear waste materials.

I've already shown you an example of a safe disposal system for this waste.

Here is what the current thinking is:
"The safety of geological disposal is widely accepted amongst the technical
community and a number of countries have now decided to move forward with
this option."
http://www-pub.iaea.org/MTCD/publications/PDF/LTS-RW_web.pdf
So when people say we don't know how to dispose of it, you can understand why this is regarded as false.

 

[lomiller]

My question is how much higher is the rate at Chernobyl now than the half-life of uranium without the chain reaction? If it's increasing the rate of fission by 50% that's pretty meaningful. If it's increasing the rate by 0.01% then it's not really worth talking about.

We don’t know how much of a the radiation being emitted by the remains of the core is due to chain reactions. It may be that no one really knows, and it doesn’t matter anyway.

The real issue is that it’s still spitting out radiation and radioactive particles at a level that will require a containment facility for thousands, possibly tens of thousands of years unless the core can be removed. The discussion around what a chain reaction is, and to what degree it’s still occurring is really nothing more than a pedantic distraction. It’s technically wrong to say no chain reaction is happening, but if you want to view it that way it doesn’t change the real issue.

 

[ginjawarrior]

I wonder how much surface and iron/other materials we'd need to power the whole planet with solar, though.

Figure 30.3. The little square strikes again. The 600 km by 600 km square in North America, completely
filled with concentrating solar power, would provide enough power to give 500 million
people the average American’s consumption of 250 kWh/d.
This map also shows the square of size 600 km by 600 km in Africa, which we met earlier.
I’ve assumed a power density of 15 W/m2, as before.
The area of one yellow square is a little bigger than the area of Arizona, and 16 times the
area of New Jersey. Within each big square is a smaller 145 km by 145 km square showing
the area required in the desert – one New Jersey – to supply 30 million people with 250 kWh
per day per person

https://www.withouthotair.com/c30/page_236.shtml

Proponents of solar just don't get the scales needed to power the whole planet with solar. There's talk about saving the environment by using solar and wind but it would cause even more environmental damage when we're already stressing the planets ability to handle it....

 

[Belz...]

The discussion around what a chain reaction is, and to what degree it’s still occurring is really nothing more than a pedantic distraction. It’s technically wrong to say no chain reaction is happening, but if you want to view it that way it doesn’t change the real issue.

At 500 Seiverts per hour it's clear that there's a sustained chain reaction going on, which means to me that much of the reactor is in a neat little pile.

So although the distinction was important, imo, there appears to be a lot more going on inside the reactor containment building than I thought.

 

[lomiller]

In the case of spent nuclear fuel, the issue has been looked at by international multi-disciplinary teams for many years. We know how to dispose of spent fuel, and that is deep geological depository. That someone might not want to use Yucca mountain only means you either over ride that or come up with a better site.

There are questions and possible issues around that as well. It's better than what's occurring now but the real best solution is to plunk the spent fuel into some variety of breeder reactor that turns it back into useable fuel.

The current US system of just leaving it in retention ponds is generally safe as long as the retention ponds are maintained and don’t suffer some natural disaster that exceeds their design specs. Leave them long enough and that’s bound to happen to some of them, but you also need to consider a failed state scenario where the ponds stop being maintained and no one can respond to deal with the problem if they do.

 

[Belz...]

https://www.withouthotair.com/c30/page_236.shtml

Proponents of solar just don't get the scales needed to power the whole planet with solar. There's talk about saving the environment by using solar and wind but it would cause even more environmental damage when we're already stressing the planets ability to handle it....

Ok so coal is too polluting, wind is insufficient, nuclear is too dangerous, hydro too limited geographically and solar too surface-intensive.

Ok, so what now?