Olkiluoto geology

[MiM]

spent nuclear fuel really includes far more radioactivity than fly ash, and it has to be dealt with in a responsible manner, which is absolutely possible.

Far more radioactivity in terms of concentration, not in total tonnage of radioisotopes. For each gigawatt of electricity produced, coal burning power stations generate more tonnes of radioisotopes in their waste than the equivalent from a nuclear power station. It is just that the coal ash dilutes the radioisotopes massively.

As I am currently very tired, I ask you to provide the references and maths to substantiate that claim. Normally I would do this the other way around.

Edit; To start with: Coal burning doesn't generate any radioctive isotopes at all, it accumulates and/or disperses them. Nuclear really generates radioactivity. Second: "Tonnes of radioisotopes" isn't a viable measurement at all. Third: Think every nuclear power plant would spew out it's waste directly into the air. Every plant would then be a continuously live Chernobyl or Fukushima. Does that sound bad or not?

[Blind groper]

Coal burning doesn't generate any radioctive isotopes at all, it accumulates and/or disperses them. Nuclear really generates radioactivity. Second: "Tonnes of radioisotopes" isn't a viable measurement at all. Third: Think every nuclear power plant would spew out it's waste directly into the air. Every plant would then be a continuously live Chernobyl or Fukushima. Does that sound bad or not?

Burning coal concentrates radio-isotopes, and the waste contains more radio-isotopes than the waste of nuclear power plants, albeit in much more dilute form. Nuclear power starts with radio-isotopes (U235 or plutonium) and ends up with different radio-isotopes. Where the radio-isotopes come from is not the point. We are talking of how hazardous a waste is, and I am saying that coal waste is only less hazardous than nuclear waste because it contains more diluent.

And why do you think tonnes of radio-isotopes is not a valid measure? it is pretty damn straight forward.

No one has even mentioned radioactivity spewing into the air,. That is a red herring.

[MiM]

Numbers math and references, please
Edit: hint: One tonne of U238 isn't really that dangerous at all, whereas one tonne of Cs137 is a whole other ballgame.

[Blind groper]

Certainly. However, Cs137 is not a major component of most waste. It is, in fact, in rather small amounts.

I understand where your line of logic is running. But, while it is a valid line of reasoning, it does not change the simple fact that the total amount of nuclear waste, in terms of radio-isotopes, whether measured in tonnes or Becquerels, is rather small. Compared to almost any other waste stream, it is not a major problem, and it can be dealt with using a number of methods, as long as people get rational, and dump irrational politics.

[MiM]

Well, Cs-137 together with Sr-90 are the major contributors to the radiotoxicity of spent fuel, at least between ~5 and ~30 years old. And it is the major source of external radiation from the waste for considerably longer time.

There are many factors, that has to be taken into account to tackle your claim. Here are a couple of examples.

One single unshielded typical LWR fuel element, will give a dose rate of 10 Sv/h at one meters distance, still after 20 years of cooling. As the lethal dose is usually taken to be 5Sv, this means, that you will probably die soon if you stand there more than half an hour. If you are cold and hug the warm element, the dose rate goes up to 100 Sv/h and you will now have only 5 minutes to get internally fried. There are hundreds of fuel elements changed in he reactor core every year.

Here is a short page on the radiotoxicity of spent fuel. So if we can trust this French governmental organisation, and look at the graph, ten year old fuel has a radiotoxicity of about 3 hundred million Sv/ton, if ingested. This means that one ton of this stuff (which is about 4 bundles) could kill more than 50 million people, if someone would, let's say, grind it up and mix it in a large batch of tomato soup cans. Calculated this way, spent fuel from one reactor core could theoretically wipe out all of humanity. You also see that the decline is pretty slow, so time helps, but not very fast. After 100 years, it has only gone down by about a factor of three.

If we calculate from that 3 hundred million Sv/ton (1e6/3E8=3.33e-3), we see that we need to ingest only 3 mg of the fuel to get a dose of one Sv, or about 15 mg to get the lethal dose of 5 Sv. This puts the waste clearly in the highest toxicity class there is (LD50 = 5mg/kg body weight, or 350 mg for a 70 kg person).

So while the amount in tonnes is small, the amount of radioactivity or toxicity is not small at all, and high level nuclear waste is nothing to play around with. That said, I do agree that we can handle it in a safe enough way, as long as we keep our cool about it.

[Blind groper]

MiM

That argument is like the argument Greenpeace use to attack dioxins. The total human production of dioxins today is less than 10 kg per annum globally. However, it is the most toxic man made substance. So it makes this material into a wonderful bogeyman for Greenpeace to exploit politically, in spite of the fact that there is so little that it is a non issue.

Sure, nuclear waste is nasty. But again, there is so little that it can be dealt with without major technical problems, if we approach the issue rationally.

[Svartalf]

Numbers math and references, please
Edit: hint: One tonne of U238 isn't really that dangerous at all, whereas one tonne of Cs137 is a whole other ballgame.

But is the CS137 produced by nuclear tech rendered to slalts? as metal or as an alloy, or glass, rather than salts, it ought not to be water soluble and hence not THAT much of a problem.

[MiM]

MiM

That argument is like the argument Greenpeace use to attack dioxins. The total human production of dioxins today is less than 10 kg per annum globally. However, it is the most toxic man made substance. So it makes this material into a wonderful bogeyman for Greenpeace to exploit politically, in spite of the fact that there is so little that it is a non issue.

Sure, nuclear waste is nasty. But again, there is so little that it can be dealt with without major technical problems, if we approach the issue rationally.

I agree that I coloured that one up a bit. But it seems like the LD50 amounts for ingested semi fresh spent nuclear fuel and dioxin are in the same ballpark, give or take a decade or so. But we produce thousands of tons of spent fuel, every year, against your claim of 10 kg of dioxin. One important difference is, that we are pretty good at keeping the fuel out of the biosphere, whereas the dioxins roam much more freely. Let us keep that fuel isolated, and not start dumping it into the sea, or throw it into old open mines, ok?

[Blind groper]

In a Scientific American article about 10 years ago, they quoted a production of about 100 tonnes per year of radioisotopes in nuclear waste globally. Assume it has increased, I doubt it is more than 200 tonnes a year today. Then, the standard procedure is to store this waste under water for many years, during which time the short half life isotopes decay. The end production of toxic radioactive waste after such storage has to be a lot less than 200 tonnes per year.

Where we get the picture distorted is that a lot of waste is mixed up with inert materials, so that the whole load of contaminated stuff is in the thousands of tonnes.

Keeping that fuel isolated long term is about the stupidest thing you can do with it. Nuclear material is only dangerous if concentrated. After all, the most common rock on this planet, granite, is 1 to 20 parts per million uranium, and at that dilution, the fissionable material is totally harmless. (Granite is slightly radioactive, and those who live in granite mountains are exposed to about 20 times the annual radiation compared to those who live on alluvial plains. Those mountain dwellers have been shown to live longer and healthier lives than plains dwellers.)

To make nuclear waste safe, it needs to undergo that storage under water for, say, 20 years, then be diluted massively to harmless levels. If that is done, it is no longer a problem. Not even a little bit of a problem. it is a problem totally solved. The only real argument is what is the best way to achieve such dilution.

[MiM]

To make nuclear waste safe, it needs to undergo that storage under water for, say, 20 years, then be diluted massively to harmless levels. If that is done, it is no longer a problem. Not even a little bit of a problem. it is a problem totally solved. The only real argument is what is the best way to achieve such dilution.

Well that's more or less what they did in Chernobyl and Fukushima, except it wasn't harmless, even though especially in the Fukushima case, most of the fuel is still in the cores. Waiting 20 years will not help much, as the most harmful isotopes (semi-short term) Cs-137 and Sr-90 hasn't even halved by then, and Plutonium will continue to be problematic for 100 000 years.

And before you claim it can be done in water: They are finding high levels of Cs-137 in fish more than 20 km from the Fukushima plant. Deliberately poisoning our environment is not a good thing to do.

http://www.bloomberg.com/news/2012-08-2 ... -fish.html
http://theintelhub.com/2012/03/30/marin ... shellfish/

BTW: natural uranium in the rock isn't healthy either. It creates radon, that is the second biggest cause of lung cancer in Finland. And it is a problematic toxic substance in water from privately drilled wells.

[Tero]

Didn't someone calculate how much U there is in a concrete apartment building?

[Tero]

Didn't someone calculate how much U there is in a concrete apartment building?

[Svartalf]

Not that much, even though we know that Brittany has a lot of cancers due to the radon gas accumulating in granite houses.

[Blind groper]

Radioactivity is harmful when concentrated. Radon is harmful when it is permitted to concentrate. This happens in certain caves, and mines, and in the basements of homes made out of granite. The solution to this problem is dilution, by means of improved ventilation. Forced ventilation if necessary.

To MiM
You said poisoning our environment is not a good thing to do, and I agree. However, appropriate dilution of nuclear waste is not poisoning our environment. With any toxin, chemical or radioactive, the key factor is dose. You can overdose by getting a solid lump, such as a particle of Plutonium, or by simply having too much in a confined space. However, as soon as you dilute the toxin sufficiently, it is no longer a problem.

The oceans of the world contain 1,000,000,000,000,000,000 tonnes of sea water. If we get 200 tonnes a year of radio-isotopes, and dump 1000 years worth in the ocean, by dissolving in strong acid, and massive dilution, the final concentration will be 1 part in 5 trillion, even if we assume none decays over that 1000 year period.

No rational thinker is going to consider that level in sea water a problem.

[MiM]

Well you try to find a way to mix it that evenly, without getting any accumulation in biota et.c. on the way. Might win you a Nobel.