Built for Eternity: The Hoover Dam | Hacker News Reader

Built for Eternity: The Hoover Dam

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34 pointsandyjohnson042 comments

Radioactive waste from spent nuclear fuel has a shelf life of hundreds of thousands of years. Maybe even more than a million, it’s not possible to precisely predict.

The fact that a journalist can write such a thing demonstrates the level to which public discourse about the sciences has sunk. We have very accurate measurements of the half-lives and decay pathways of all the isotopes found in non-trivial quantities in spent nuclear fuel, and it is indeed very possible to predict the level of radioactivity at a given time in the future.

Not if we invent methods to reduce the shelf life. Difficult to predict indeed :)

Not too difficult, with a high neutron flux, the waste can be "burned" and that half life can be dropped to something manageable on a human timescale.

That involves either creating more waste, or a sizable particle accelerator though. It's not too difficult, but it's quite expensive on a large scale to say the least.

Breeder reactors burn up >90% of what we call "waste" now, leaving behind only relatively short-lived isotopes. They're not more expensive than normal nuclear power plants, but because they can be used to breed weapons grade plutonium we don't build them.

We don't, and that's a shame. They /can/ be used to breed plutonium, or they can me used to transmute into non-proliferation concerned materials. (Plutonium may be an interm step still; you'll need to read further on the Nuclear Fuel Cycle)

France does this still actually, but we do not. Too toxic an issue. (no pun intended.)

I've always been perplexed though at the 10,000 year requirement of the repository, as if envisioning all progress stopped for that period of time. Would this not be considered an interim step if, one hundred years from now, we found an economically sound alternative not available earlier?

I am not suggesting for a moment that this become a "kick the can" solution, but rather, the issue of nuclear waste is an ongoing project of management, not simply "stick in the ground for 10,000 years." If it turns out that in 200 years, we still do not have a better way of dealing with it, then take it out of the vault and put it in a better one.

Might be a good job for CERN.

The only circumstances I can think of in which the decay of radioactive waste might be unknown is in the case of mixed waste where the content or origin is unknown or ambiguous. Some old waste material might fall into that category, but I don't think that recent spent reactor fuel would.

My understanding is that radioactive emissions are readily measurable so what elements/isotopes are involved should be identifiable and therefore the rate at which these will decay will be predictable - this could well be wrong!

One potential other risk is chemical instability of nuclear waste materials - that has caused lots of problems e.g. the Kyshtym disaster:

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

Edit: Modified the first part to make it clear that I should have been asking a question rather than making a statement!

Is it possible to precisely identify the composition of a body of mixed waste solely from its emissions? Wouldn't chemical analysis of a sample be necessary?

Two substances might emit the same kind of particles, but their rate of decay will be different.

Measuring the emissions of a container over a period of several years will probably yield enough data points to solve for all of the unknowns.

Also the energies, specifically of the more penetrating gamma rays (very energetic photons). And the more dangerous stuff has shorter half-lives, so it wouldn't take all that long to get the full picture.

WRT to nuclear weapons, we can determine what the fissionables were, where they were mined, and some details of design all from sniffing the air downwind.

1) Yes its extremely trivial, aside from shielding and non-homogenous and screwing up issues.

2) Yes because for example glass is stable in acid and unstable in some alkali so neutralizing the "stuff" before mixing it into glass bricks for all eternity would be Highly advisable if you want the glass brick to be unchanged for 100K years or 1M years or whatever. Aside from acid/base reactions with the glass itself there are solubility situations where a simple reaction might convert some radioactive salt that is highly soluble in water to something that's essentially waterproof. Note that the glass for vitrification is not exactly mere window glass, its some weird stuff, and adjusting its mix might help depending on what you're trying to dissolve into it.

(edited to extend answer #2, most of the waste you put into a vitreous block is not radioactive, you can't use the gear from answer #1 to tell what most of it is made out of)

On a high level this overall discussion has gone off the rails because the 100K and 1M numerological numbers come from glass vitrification and stainless steel corrosion theoretical studies; it has little to nothing to do with radioactivity; you could vitrify coal ash or industrial waste or Atari 2600 game cartridges the same way for 1M years if you felt like it. Or at least people think that storage tech will last 100Kyrs Of course radioactive waste is harmless once it finished decaying whereas arsenic is forever so its kinda pointless to try and stockpile industrial waste for 1Myrs whereas nuclear waste is the only kind of waste that actually goes away with time.

No human has ever made an industrial artifact that's lasted 1M years so things are kind of fuzzy at that kind of extrapolation.

1) Is this because the emitted particles have different energies when they come from different isotopes?

Yes. The resolution and dynamic range you can get with modern gear is pretty impressive. Check out images.google.com with terms like "gamma spectrum". Also different kinds of particles. Also you can zap things with neutrons (and other things) and the reactions tend to be rather unique.

Given a large enough amount of money to outfit a lab, its very fast and easy to tell whats inside an unshielded box. If its a thick enough shielded box, exact minimal design probably classified, then you'll have to crack the box open or stick a sensor in a hole.

Its trickling down to consumer level. Junkyards can now afford an x-ray zapper than analyzes the exact metal alloy of scrap that comes in. Its interesting that when I was a kid things like FLIRs and xray analyzers were very star trek, but within my lifetime they're going to be nearly consumer goods. If you thought police visual cameras and airport xray scanners were controversial, wait until every podunk police dept has 500 FLIR cameras on lampposts and every car that drives by is remotely analyzed for drug or gun or explosive signatures all for your "safety".

Contaminated lumber, clothes, plastics, that mixed material can be difficult to valuate indeed and uses a lot of space too, so it gets incinerated.

The writing quality was a lacking overall. I actually found that uplifting, I'm not a great writer but if VICE is willing to publish this story, I shouldn't be as self conscious about my own work!

In other words, not only the article sucks, it also teaches others not to care about quality. :(.

I find it frustrating that so much journalism these days exaggerates environmental issues, with any factual errors seemingly brushed off as just showing an excess of virtue.

I visited Hoover Dam a couple of years ago. The physical scale of the thing is just astonishing. You can look at it from the top, from a bridge nearby, from inside looking out and up, and it is just mind bogglingly big. Then there is the audacity of what it does. It reroutes an entire river and moves the water through these enormous turbines to generate power. Actually, the individual turbines are surprisingly small considering what they do, (to me anyway). Sort of the same magnitude as one of those stills in Islay that distill whisky.

But one of the most amazing things, neglected by the article, is this: The project was done ahead of schedule and under budget. It went from concept to working machine in a very short period of time. It seems to me that this was peak capitalism, working exactly as it should. I cannot conceive of anything so large today being built ahead of schedule and under budget. The parasites at Bechtel and Halliburton and whoever else would get involved would find ways to suck up time and money forever, and then the flaws would be discovered after all the checks had been cashed.

As they say, it was a simpler time. The dam builders hired unemployed workers, paid them cheaply, and violently broke up any attempts at unionizing or collective bargaining. Over 100 workers were killed during construction. There was of course no environmental impact statement or review; to the contrary, it was broadly taken for granted that it was man's destiny and duty to "improve the land" through massive engineering projects.

Think about the same project being attempted now. Unemployment is now officially pretty low, but I believe the numbers omit people who are "underemployed", (e.g. part time when they would prefer full, no longer looking for work). Pay would likely be very low, and unions have been pretty much busted, so no more collective bargaining. Maybe fewer would die. Environmental review would probably take place, but a large enough corporation seems to be able to bully its way through anything. The main difference I see is that corporations have become more expert at modifying the system to suit their own interests.

And of course, this country is no longer capable of doing large projects (or even basic maintenance) because congress is completely broken. How's that highway trust fund coming along?

As I get older, among my regrets are not having gone to see either the Grand Canyon, or the Hoover Dam. I have half-made plans to take the trip, some day.

They aren't that far apart. If you haven't gone by now, I assume it's because you can't stand Las Vegas? Me too, but there was an event there that I couldn't resist, and so Hoover Dam was just a short drive.

> I assume it's because you can't stand Las Vegas?

Haha, I have no idea because I haven't been there, but you're right that I can't stand even the idea of Las Vegas :-)

I posted this because I'm fascinated by the intersection of architecture and long-term thinking. Example: the sculptures and terrazzo floor at the Hoover Dam [1], the Long Now clock, the Georgia Guidestones [2], the design of the Arctic seed vault [3]. When people design for the very long term they can produce very interesting results.

The scale of the landscape described in the article seemed to match the depth of time involved in the various projects.

[1] http://www.usbr.gov/lc/region/pao/brochures/wingedfigures.pd...

[2] https://en.wikipedia.org/wiki/Georgia_Guidestones

[3] https://en.wikipedia.org/wiki/Svalbard_Global_Seed_Vault

Communicating 10,000 years into the future is certainly a challenge but I just realized that this idea of warning people of a radioactive waste dump is surely not actually worth a huge effort. Being just one place, only a very small number of people will be able to visit it up close where it's dangerous. Isn't that about the same level of danger as the existence of poisonous plants, carnivorous animals, high risk places for lightning strikes, drowning, etc? And massively safer than disease, including genetic disease and inbreeding. Perhaps the best solution is just to not bother warning anyone if our society oneday forgets about it. If it affects enough people, they'll figure out the connection to the site themselves.

What are they going to think about us if we let their archaeologists run into death without even trying to warn them...

"not actually worth a huge effort"

I think I'd argue that if we (human civilisation) are going to create a very long term hazard such as a radioactive waste dump, then we have a moral obligation to the people who it might one day endanger. Even if the number of such people is small, I think we still have a duty to them. We had a choice to build this thing, but they won't have a choice about living with it.

A cynical view is that the effort that went into the WIPP marker design was an effort to pre-empt objections to it being built. Gregory Benford (a physicist and science fiction author) was part of the design team, and he devoted part of a book, Deep Time [1], to his experience. Whatever the ultimate motivation of the US DOE and others, it seems like the design team took the ethical component of their task seriously.

[1] http://www.physics.uci.edu/~silverma/benford.html

> a very long term hazard such as a radioactive waste dump

That part is an oxymoron because radioactive waste decays.

If you really want to stack future archaeologist bodies like cordwood, think of industrial waste, or coal plant fly ash waste, or mining waste. The half life of cobalt-60 is about half a decade... in a million years that a pure ingot would be "mostly harmless", because 1 over n to the 200000th means there won't be much Co-60 left in that ingot... For a good laugh assume a 1 Kg ingot how many years until the last atom decays? Sooner than you'd think. On the other hand arsenic, cyanide, and organometallics are forever, in a billion years you could crack open an industrial storage vat and kill everyone at an archaeological dig. Assuming their biochemistry remains the same, and they're not using drones to do the dig...

"That part is an oxymoron because radioactive waste decays."

Its a hazard until the waste decays. If the waste takes a long time to decay then its a long-term hazard. Plutonium-239 has a half-life of 24k years, for example. Other transuranic isotopes have half-lives measured in hundreds of thousands, or even millions, of years.

I agree with you about industrial waste, though.

Why does nobody get worked up about unknown civilizations 10,000 years in the future stumbling across a chemical waste dump and getting killed by it? It's very odd that all the emphasis is on nuclear, when nuclear waste dumps will be a tiny fraction of the hazards created by current civilization.

I'm sure your Mother told you 'two wrongs don't make a right' as a child though.

And?

If one guy steals a hat, and another guy murders the storekeeper, it's reasonable to ask why people are more upset about the hat than the murder, and that does not in any way justify the hat.

Into eternity is a documentary on a long term nuclear waste storage facility in Finland. It is fascinating.

https://en.wikipedia.org/wiki/Into_Eternity_(film)

Thanks. Looks very interesting, and I've just bought a copy from Amazon.

The trailer is at https://www.youtube.com/watch?v=GmWadizC8AQ.

The concept that you are interested in is known as deep time (https://en.wikipedia.org/wiki/Deep_time) and there is a book by the same name by Gregory Benford (http://www.amazon.com/Deep-Time-Humanity-Communicates-Millen...) that explores the idea in greater depth.

Thanks! I'm familiar with the term, and I have a copy of the Benford book that I bought when it was published. The sections on the WIPP marker and the Cassini message are particularly interesting.

If you find the Hoover Dam and the region a little bit fascinating, play Fallout: New Vegas. It plays a central role there, and the game is also one of the best RPGs of the recent years, maybe the best.

"That a 10,000 year storage solution was nowhere near long enough to inculcate the Earth from the true shelf-life of the waste, which is realistically thought to be dangerous for many times that length of time."

With some definition of "dangerous" sure. After just few hundred years, it's only slightly more dangerous than naturally occurring uranium. The other difference is that natural uranium is dispersed more and guarded less.

"Final disposal of high-level waste is delayed for 40-50 years to allow its radioactivity to decay, after which less than one-thousandth of its initial radioactivity remains, and it is much easier to handle. --- After being buried for about 1000 years most of the radioactivity will have decayed. The amount of radioactivity then remaining would be similar to that of the corresponding amount of naturally-occurring uranium ore from which it originated, though it would be more concentrated."

Source: http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Nuclear...

And as I always point out in these discussions, the long life of nuclear waste isn't a problem, it's a bonus. We deal with chemical poisons all over the place which never decay, and yet we treat them with much less care than nuclear waste.

Somehow, for some reason I can't fathom, people get much more worked up about "this waste will remain dangerous for 10,000 years" than "this waste will remain dangerous until the heat death of the universe."

A few links about the WIPP marker design project:

Expert Judgment on Markers to Deter Inadvertent Human Intrusion into the Waste Isolation Pilot Plant. Sandia National Laboratories report SAND92-1382 / UC-721. http://prod.sandia.gov/techlib/access-control.cgi/1992/92138...

Ten Thousand Years of Solitude? On Inadvertent Intrusion into the Waste Isolation Pilot Project Repository. Los Almos National Laboratory. http://www.iaea.org/inis/collection/NCLCollectionStore/_Publ...

Designing for Deep Time: How Art History is Used to Mark Nuclear Waste. Kelli Anderson (MS Thesis), 2005. http://www.kellianderson.com/MSthesis.pdf

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