Educating the general public about pro nuclear energy?

[russ_watters]

Good, so we are back to square one. How to bury it properly for ten thousand years. Please go back to this post:
https://www.physicsforums.com/threa...ro-nuclear-energy.914038/page-10#post-5769055

With all of your unseriousness/sarcasm, it is difficult to tell if you even understood the point you were responding to (from me) or had any serious point of your own to make. So instead of going back, please try again to make your point in a serious way. Because I'm entirely serious when I say it doesn't need to be buried at all, much less for ten thousand years.

 

[SredniVashtar]

Unseriousness? C'mon, I've seen much less mutatio controversiae, straw men and logical fallacies in a new age newsgroup.
Let's take the above mentioned post, for example:

I said:

"As for the wastes, that 3% that decays between 1000 and 10000 years [...] can you be sure they will be taken care of after all that time? Will you write instruction in English, Latin, Sumerian, Hieroglyphs or Linear A? Ten thousand years is a long time."

You replied (in a highly serious way, let me add):

"So what/who cares? If civilization has fallen so far that whomever is left can't understand any current language or a giant sign with a skull and crossbones on it, they will certainly have bigger problems to be concerned about than what is in that barrel."

And now, you say you are entirely serious when you decide to change the subject (technically it's a mutatio controversiae) and say that it does not have to be buried and much less for ten thousand years. So, Why didn't you just say so in the first place? You could not defend that? Wanna use "protect" instead of "bury" and "five thousand years" instead of ten? I did not pull those figures out of a hat, I took them from the World Nuclear Association. Non exactly Green Peace.

 

[russ_watters]

Unseriousness?

Yes.

I said:
...
You replied (in a highly serious way, let me add):
...
And now, you say you are entirely serious when you decide to change the subject (technically it's a mutatio controversiae) and say that it does not have to be buried and much less for ten thousand years.

There is no change of subject there. Not having to be protected for a very long time means it doesn't need to be buried. So: do you have a serious response to that or not?

I did not pull those figures out of a hat, I took them from the World Nuclear Association. Non exactly Green Peace.

So what? Does that mean you don't understand what their point is and are just repeating them without being able to justify why it matters?

Also, since you didn't quote your own follow-up in the above exchange, I will take that as an acknowledgment that it wasn't serious. So moving forward, please make an effort to present your arguments more seriously.

 

[SredniVashtar]

There you go:

""As for the wastes, that 3% that decays between 1000 and 10000 years [...] can you be sure they will be taken care of after all that time? Will you write instruction in English, Latin, Sumerian, Hieroglyphs or Linear A? Ten thousand years is a long time."

Awaiting a serious answer.

 

[mfb]

Do we have to make sure that it will be taken care of?
That is the first question.

Is there any relevant danger to humans if no one takes care of it?

My comment about eating it was serious. Is there any risk that someone goes to nuclear waste and physically eats it? It is a collection of mainly heavy metals.

 

[russ_watters]

There you go:

""As for the wastes, that 3% that decays between 1000 and 10000 years [...] can you be sure they will be taken care of after all that time? Will you write instruction in English, Latin, Sumerian, Hieroglyphs or Linear A? Ten thousand years is a long time."

Awaiting a serious answer.

You're just reposting your [implied] claim, which has already been responded to, and ignoring the response you got. What I want a serious answer to is why you think it is necessary that we must assure *today* that it "be taken care of" for that amount of time.

As I said, due to your unserious previous response it isn't clear that you understood the objection you were given -- and now that you have ignored it completely.

 

[SredniVashtar]

"When we consider the longer-lived activities that might characterize spent fuel elements, we are interested in a time scale of the order of years. Figure 13.30 shows the activities of the long-lived fission products and actinides. After reprocessing, these activities must be isolated from biological systems for times of the order of 10^5-10^6 years. Several schemes have been suggested for achieving this isolation but no system has yet been adopted that can guarantee isolation over this time scale. Any leakage into groundwater or the food chain would be expected to result in an increase in deaths from cancer".

Kenneth Krane, "Introductory Nuclear Physics", 1988
A lot o time has passed, since then. Fast forward to february 2016, last update to the World Nuclear Association "Radioactive Wastes" page.

"The radioactivity of high-level wastes decays to the level of an equivalent amount of original mined uranium ore in between 1,000 and 10,000 years. Its hazard then depends on how concentrated it is.[...]
A small volume of nuclear waste (~3% volume of total waste produced) is long-lived and highly radioactive and requires isolation from the environment for many thousands of years.[...]
Waste is converted into a stable form that is suitable for disposal. In the case of high-level waste, a multi-barrier approach, combining containment and geological disposal, ensures isolation of the waste from people and the environment for thousands of years.[...]"

"Many people quite reasonably feel that the nuclear industry shouldn't continue operation without having a solution for the disposal of its radioactive waste. However, the industry has in fact developed the necessary technologies and implemented most of them[...]"
"Today, safe management practices are implemented or planned for all categories of radioactive waste. Low-level waste (LLW) and most intermediate-level waste (ILW), which make up most of the volume of waste produced (97%), are being disposed of securely in near-surface repositories [...]"
"High-level waste (HLW) is currently safely contained and managed in interim storage facilities.[...]
These facilities also allow for the heat and radioactivity of the waste to decay prior to long-term geological disposal.[...]
In the long-term however, appropriate disposal arrangements are required for HLW, due to its prolonged radioactivity. Disposal solutions are currently being developed for HLW that are safe, environmentally sound and publicly acceptable. The solution that is widely accepted as feasible is deep geological disposal,[...]"

So, my question still stands.
[edited by mod]

 

[russ_watters]

...
So, my question still stands.

None of that was responsive to the answer/follow-up question you got. I think therefore that your answer is that you haven't put any thought into the question. What I'm not totally sure of is if you realize it and are dodging or really don't understand that there must be a "why". So I'll lay it out for you. It is two-pronged:

The US government does not have the responsibility to protect you completely from all dangers today(1), much less perpetually(2).

1. For all the protection we get from the US government, planes and cars still crash, buildings burn and collapse and people die from inhaling the pollutants of other sources of energy. The government is required to make a reasonable effort to make you pretty safe -- it is not required, nor is it even possible, to make you totally safe. If it were, we wouldn't be using lead or any other heavy metal at all; we'd be collecting and burying it all in the geological storage facilities.

2. If the US government ends and enough people and technology are destroyed throughout the world so that no one understands English anymore - civilization literally gets set back to the stone age - the responsibility of the US government will have ended. Indeed, at that point the US government will have already failed in its responsibility. Any additional harm potentially caused by someone digging up nuclear waste (or finding it in a warehouse) will pale in comparison to that larger failure. So it is illogical to try to plan for it. You could make the similar case that in 100 years my house will become so old that it is dangerous to live in. But if the US government has collapsed and people are back to the stone age and someone needs a roof, maybe they'll choose to live in it. And maybe it will collapse on them and kill them. That will be yet another failure of the US government to provide perpetual protection. Why aren't we planning for that?

 

[mheslep]

So, my question still stands.

The quotes you partially reference from WNA are from a page on "myths and realities" about nuclear waste, a contrast not clear in the passage you quoted. In particular, you omitted parts of the reference which place radioactivity in context.

From the WNA reference, myth #5:

5. Nuclear wastes are hazardous for tens of thousands of years. This clearly is unprecedented and poses a huge threat to our future generations in the long-term

My take is your thesis in the above posts are summarized as myth #5 by WNA.

And the entire body of response #5:

Many industries produce hazardous waste. The nuclear industry has developed technology that will ensure its hazardous waste can be managed appropriately so as to cause no risk to future generations.

In fact, the radioactivity of nuclear wastes naturally decays progressively and has a finite radiotoxic lifetime. The radioactivity of high-level wastes decays to the level of an equivalent amount of original mined uranium ore in between 1,000 and 10,000 years. Its hazard then depends on how concentrated it is. Compare this to other industrial wastes (e.g. heavy metals such as cadmium and mercury), which remain hazardous indefinitely.

Most nuclear wastes produced are hazardous, due to their radioactivity, for only a few tens of years and are routinely disposed in near-surface disposal facilities. A small volume of nuclear waste (~3% volume of total waste produced) is long-lived and highly radioactive and requires isolation from the environment for many thousands of years.

International conventions define what is hazardous in terms of radiation dose, and national regulations limit allowable doses accordingly. Well-developed industry technology ensures that these regulations are met so that any hazardous wastes are handled in a way that poses no risk to human health or the environment. Waste is converted into a stable form that is suitable for disposal. In the case of high-level waste, a multi-barrier approach, combining containment and geological disposal, ensures isolation of the waste from people and the environment for thousands of years

[emphasis mine]

One area of agreement in all the above posts in this thread seems to be that nobody wants significant concentrations of radioactivity, cadmium, or mercury dumped into the food chain or water supply. This is different from suggesting a ban on radioactivity (or elements of the periodic table.)

Further, in your quote above from WNA on '3% volume', a sentence was clipped which I include here:

...Most nuclear wastes produced are hazardous, due to their radioactivity, for only a few tens of years and are routinely disposed in near-surface disposal facilities. A small volume of nuclear waste (~3% volume of total waste produced) is long-lived and highly radioactive and requires isolation from the environment for many thousands of years.

 

[SredniVashtar]

Still the same logical fallacy: since there are other poisons, this poison is not poisonous.
Also, my quotes are referring to facts, not the myth part.
I understand that you would prefer to talk about the 97% short-lived part of the waste, but - for the n-th time - this is not what I am talking about. I am talking about the 3% long-lived part that according to Krane and the Wolrd Nuclear Association requires long term storage (stated as a fact, not a myth).

And the bottom line of Russel's answer is "if the US government is no longer in charge, who cares?".
And now I also get censorship in my post and a threat to be banned from the thread (from one of the people I am arguing with)
Not exactly mature behavior.

 

[mheslep]

...planes and cars still crash, buildings burn and collapse and people die from inhaling the pollutants of other sources of energy.

And enormous coal-ash slurry dumps collapse releasing 4.2 million m^3 of silica and heavy metals into the surrounding environment and rivers in Kingston, TN, the largest in US history. Yet no mass marches occurred; nobody but @Astronuc even mentioned the spill on PF, and Jane Fonda did not make a "you're lucky to be alive" movie about mountains of sludge.

 

[mheslep]

Still the same logical fallacy: since there are other poisons, this poison is not poisonous.

No, the assertions made above are that there are many possible toxins, and that the toxicity comes from the dose. The fallacy here is yours, textbook special pleading, e.g. treat my complaint in isolation without justification.

..I am talking about the 3% long-lived part that according to Krane and the Wolrd Nuclear Association requires long term storage (stated as a fact, not a myth).

The WNA states " ... requires isolation from the environment for many thousands of years". Some radioactive isotopes in high concentration, and drums of cadmium for instance, should be not be dumped in the food or fresh water supply, not ever for the drum of cadmium, and not for thousands of years for some isotopes.

 

[jim hardy]

I am talking about the 3% long-lived part that according to Krane and the Wolrd Nuclear Association requires long term storage (stated as a fact, not a myth).

So,

just why does it matter that it's dangerous for a long time?

 

[mfb]

Still the same logical fallacy: since there are other poisons, this poison is not poisonous.

As far as I can see, you keep arguing "since it stops being poisonous after a while, it must be particularly dangerous before".

Sure, if we had a magic wand to make nuclear waste disappear, we would do that. But we don't have the question "do we want nuclear waste or not". We have the question "do we want to operate nuclear power plants or not?". And we have to consider the benefits of nuclear power, and compare the harm of it to the harm of other electricity sources. Comparing nuclear waste to the waste of coal power plants or photovoltaics production, for example, is important. Considering nuclear waste without considering anything else is one-sided and cannot lead to educated decisions.

 

[russ_watters]

And the bottom line of Russel's answer is "if the US government is no longer in charge, who cares?".

A point to which you clearly have no response, since you have repeatedly declined to respond to it.

And now I also get censorship in my post...

I thought I was doing you a favor by editing-out a part of a reference to a personal communication. I did not remove any of the content as part of the discussion.

 

[nikkkom]

Nuclear waste mainly consists of nuclides with shorter half-life than uranium. It reaches the activity level (per mass) of uranium within 1000-10000 years, afterwards it has a lower activity (see the plot above).

The activity of uranium ore is not particularly benign. You wouldn't want to live in a house where floor is made from it, that's for sure.

Uranium radioactivity is mostly alpha and thus easily shielded. If you isolate it very well (including air-tight, for radon emissions), then it becomes almost as safe as granite. This shielding can be rather thin, ~1 mm.

But nuclear waste activity is qualitatively different from uranuim. It has a substantial gamma component, both direct from e.g. Cs-137 and also secondary gammas from beta electrons. Apart from well-known 30-year half life culprits, there are 200k year half life Tc-99 whose betas are 300 keV, and Sn-126 is both beta-active and has a strong gamma-active daughter, Sb-126. You can't wait those out in 1000 years, and shielding from gammas needs to be, as a minimum, some 5 centimeters if it's steel, tens of centimeters if it's concrete.

 

[nikkkom]

The radioisotopes with long half-lives are mostly alpha emitters that dose by ingestion, with no penetrating power. After 500-1000 years the radioactivity of a ton of spent fuel is on the order of that from a ton of Uranium ore dug from the ground.

Let's look at the concrete example of real-world nuclear waste. This is the state of the art in nuclear waste storage, the French vitrification technology and its final product, "Universal Canister-Vitrified", or UC-V (not mentioned in the table that it has 5 mm thick steel walls):

(UC-C is a similar canister for compacted metal parts of spent fuel assemblies, not relevant for my purposes)

This is roughly what one ton of spent fuel looks like after reprocessing.
Check out the last item in the table. 14000 grays per hour of gamma. In "old units", it's some 1.4 *million* R/h. Please, never, ever even think about coming anywhere close enough to touching that thing.

Let's see... if it's mostly from Cs-137 and Sr-90, then every 30 years it is halved, every 300 years it is reduced by ~1000 times. So, in 600 years this canister would emit 14 mGy/h ~= 14 mSv/h. in 900 years, 14 uSv/h ~= 122 mSv/year. World average natural background is 3 mSv/year.

After about ~1000 years, other isotopes (e.g. Tc-99) start being important. So this canister won't become significantly more safe after that time.

 

[mfb]

The activity of uranium ore is not particularly benign. You wouldn't want to live in a house where floor is made from it, that's for sure.

I don't make my house floor out of uranium ore, and I don't make it out of nuclear waste either. Not the surface, and not the material 5 cm below the surface either.

Please, never, ever even think about coming anywhere close enough to touching that thing.

You cannot touch that thing. Because it is enclosed in more shielding.
Directly after reprocessing there are many shorter-living isotopes in it, so initially the activity will go down faster.

 

[nikkkom]

I don't make my house floor out of uranium ore, and I don't make it out of nuclear waste either. Not the surface, and not the material 5 cm below the surface either.

Exactly my point. Uranium ore is not a benchmark of safe material.

You cannot touch that thing. Because it is enclosed in more shielding.

It can not be enclosed during transport from vitrification facility to short term storage, and some years later, from short term storage to "E/EV/SE storage" which is designed for <500 Watt heat load.

Directly after reprocessing there are many shorter-living isotopes in it, so initially the activity will go down faster.

I'm not that sure about the "many" part. French do not reprocess the fuel right after they pulled it from the reactor. They let it cool for ~4 years. Thus, for example, 75% of Cs-134 is already gone by the time UC-V glass is poured. Which isotopes do you have in mind?

 

[mheslep]

Uranium ore is not a benchmark of safe material.

Safe in what context? Dumped into the food and water supply? No. In contact handling in mining operations, military munitions, enrichment facilities, or even that old uranium glass fixture sitting in your great aunts living room? No problem.

 

[nikkkom]

Safe in what context?

In the context you used it: "look, in only 900 years nuclear waste is as safe as uranium ore". Which is not a safety benchmark I am agreeing to.

Military munitions. First, they don't contain ore, they contain uranium metal. Which is ~8 times less radioactive, since all daughters are removed. Second, uranium metal in tank and GAU-8 30mm projectiles is not exposed, it's jacketed by other metals. (Not that complaints about "uranium in bullets is bad for your health" strike me as making much sense. If you are being fired upon by GAU-8, radiation from uranium is the least of your concerns...)

Enrichment facilities. They don't contain ore either, and they don't let people to come in touch with UF6 (it is unstable to water and forms corrosive products).

Uranium glass, again, does not contain ore, and U content is about 2%. Even after 900 years, vitrified waste is many orders of magnitude more radioactive (mainly due to gammas not shielded).

 

[russ_watters]

In the context you used it: "look, in only 900 years nuclear waste is as safe as uranium ore". Which is not a safety benchmark I am agreeing to.

What @mheslep was asking (and now I am), is what is the benchmark you would agree to?

Surely you are not suggesting, as you seemed to before, that it should be safe enough to build household flooring out of it?

And surely you must see the logic in the "safer than when we dug it out of the ground" benchmark don't you? At that point we could literally put it back where we found it and the location we found it would be no worse off for having it back.

 

[mheslep]

They let it cool for ~4 years. Thus, for example, 75% of Cs-134 is already gone by the time UC-V glass is poure

At creation, CS 134 (1300 Ci/gm) is more than 100x hotter than Cs 137 per gram. After 2 half lives, the original mass of Cs-134 and decay products is still ~3X hotter than Cs 137, and 134 is also a strong gamma emitter. Twenty years, and the 134 is essentially gone.

 

[mfb]

Exactly my point. Uranium ore is not a benchmark of safe material.

It is. Uranium ore has been underground for billions of years. No one seems to be scared by that. Why should people be scared of nuclear material with the same activity, stored at locations that are better protected than the uranium mines?

It can not be enclosed during transport from vitrification facility to short term storage, and some years later, from short term storage to "E/EV/SE storage" which is designed for <500 Watt heat load.

Castor containers can handle tens of kW of heat. It can be contained, transported and stored easily.

Thus, for example, 75% of Cs-134 is already gone by the time UC-V glass is poured.

That is still 25% left that will decay within a few more years, and dominate the activity for a while. Typically the overall activity at a given time is dominated by just 1-2 isotopes, starting from short-living ones and transiting to longer-living ones once the short-living isotopes are gone. That leads to the characteristic wobbly shape of the overall activity in double-logarithmic plots.

 

[nikkkom]

> Thus, for example, 75% of Cs-134 is already gone by the time UC-V glass is poured.

That is still 25% left that will decay within a few more years, and dominate the activity for a while. Typically the overall activity at a given time is dominated by just 1-2 isotopes, starting from short-living ones and transiting to longer-living ones once the short-living isotopes are gone. That leads to the characteristic wobbly shape of the overall activity in double-logarithmic plots.

What isotopes, in your opinion, dominate initial radioactivity from UC-V canister?

 

[nikkkom]

And surely you must see the logic in the "safer than when we dug it out of the ground" benchmark don't you?

Is it indeed safer? Compare uranium ore's gammas with French vitrified waste.

And secondly, why does US not do even what French are doing, which is at least converting spent fuel to this insoluble, chemically stable glass form? Hanford Vit Plant is what, costs $16B to date, not finished yet, and also even when completed, it can't reprocess fuel, it can only vitrify existing Hanford waste. I'm not feeling optimistic when I see this approach to nuclear waste treatment. "Safe vitrified glass 900 years later" is not what's happening in US, it's handwavium.

 

[mheslep]

why does US not do even what French are doing,

Politics driven by Plutonium separation in reprocessing.

 

[russ_watters]

Is it indeed safer? Compare uranium ore's gammas with French vitrified waste.

You need to answer the question you were asked. This response makes it look like you don't have an answer/no level of safety would satisfy you. Is that the case?

 

[mfb]

Is it indeed safer? Compare uranium ore's gammas with French vitrified waste.

Gamma radation doesn't penetrate hundreds of meters of rock. And vitrified nuclear waste is less likely to leak than uranium ore that has not been vitrified.

 

[nikkkom]

What @mheslep was asking (and now I am), is what is the benchmark you would agree to?

Vitrified waste stored for ~100 years for cooldown, then dropped down 8 km into boreholes in a subduction zone would be enough for me. No one has full working plans to do something like this. French are the closest.