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Comment by apsec112 | Hacker News Reader

We should just assume that nuclear waste lasts forever, like a lot of chemical waste does, and then treat it the same as the equivalent class of chemical waste. When someone says "10,000 years", people start thinking about how to wait it out. When someone says "forever", people give up on waiting it out, and start thinking about more realistic safety measures.

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I'm curious, what chemical waste can you not safely dispose of? All organic compounds can be incinerated at a high enough temperate to destroy them (even nerve agents). The only thing I can think of would be metal poisons, but even those can be turned into a form that is less toxic.

Don't think there are any non-toxic forms of mercury or arsenic. There are forms that are less bioavailable, but that's equally true of nuclear waste.

A lot of metals can be converted into insoluble, inert minerals that have low-to-no toxicity. Mercury can be converted to mercury (II) sulfide which is insoluble in water and has no vapor pressure.[1]

[1]https://en.wikipedia.org/wiki/Mercury_sulfide

Except when you heat it. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2755212/

Also, cost must be a factor. Turning materials back into ore is extremely expensive.

Well I guess nothing is truly non-toxic. If you heat water high enough it could create hydrogen and suffocate you.

It takes some serious equipment to heat water anywhere near that high. For cinnabar you just need fire. This is not an artificial distinction.

If you still don't see it, maybe picture yourself standing near a burning warehouse full of water versus standing near a burning warehouse full of cinnabar?

http://www.toxipedia.org/display/toxipedia/Dioxin

Has a worst case half life of 50 years.

http://www.ejnet.org/dioxin/

Lists very small quantities as still quite dangerous to reproduction or causing cancer in exposed subjects.

But on a 10,000 year scale I fail to see how it would still be a problem. A few hundred, definitely still risky.

I went to high school next to a dioxin superfund site [1]. They incinerated it (I could see the smokestack from the school) and supposedly it's all cleaned up now [2]. We'll see how we all turn out.

[1] https://en.wikipedia.org/wiki/Times_Beach,_Missouri

[2] https://clu-in.org/download/remed/incpdf/times.pdf

A school within line of sight of a smokestack burning dioxins is something that should not even exist.

An incinerator outgassing smoke toxic to surrounding people is something that should not exist. Proximity to a school is irrelevant, except for irrational fearmongering.

I disagree. Developing tissue will have to live for much longer than older folks and any kind of cumulative toxins or hard to break down toxins have a lot more chance to do harm in children than in adults.

Anything organic can be safely destroyed through careful incineration. PCBs (related to dioxins) need a really high temperate to be destroyed, but can be.

I am pretty sure that long before 10 000 years has lapsed, this so called waste is no more considered waste. For example, my understanding is that you can use current waste as a fuel in thorium cycle.

The plan in the US was to enrich waste in breeder reactors, mix in some fresh fuel, and re-use it. It was the nuclear fuel cycle. Lots of resources on the technology.

There were two problems. The use of breeder reactors had some proliferation concerns: they can be used to make warheads. Not a big deal in the US, as the US can already make warheads, but harder if you want to export nuclear waste reprocessing to other countries.

Transporting the waste was deemed risky. More so after 9/11, as fresh waste is so radioactively hot, it needs to be kept in water, or it will overheat. If you crash a plane into a transport vehicle, or a re-processing plant, it will create quite a mess.

So there is no way the nuclear waste will stay in the ground for 10,000 years. I suspect it will be less than a hundred years before someone digs it up, and reprocesses it.

Burying nuclear waste is itself waste.

This is something I've always wondered about, especially when confronted by environmentalist camps that oppose nuclear power.

Nuclear fuel recycling seems totally viable, and I imagine nuclear "waste" could be reprocessed and used for as long as there are fissionable products left in it. At which point it would pose minimal danger and save us a boatload on 10,000 year warning signs.

It's viable in all ways except political.

People are scared by the phrase 'breeder reactor'; which is poor marketing, calling it a 'waste reduction reactor' is slightly longer, but also more accurately describes what it does and sounds a LOT better.

I think it may have been a result of Fukushima, but I gained an interest in the topic and spent a few tens of hours researching. A proper waste reduction reactor produces three categories of radioactive material.

* Stuff that is so crazy hot it'll cool off in a 'short' period of time.

* Stuff that is good for use in reactors (a subset of the above).

* Stuff that will take a LONG time to decay; which means that it is active, but very very slowly emitting.

In reality 10,000 yrs is probably longer than humans will be relevant on Earth.

Hm. One million years an counting so far?

But we've only been relevant for ~7,000 and if we do not make the Earth inhospitable ourselves in the next 10k years then the chances of a cataclysmic event are ever increasing to assist us. 99.9% of all animals ever to exist on the Earth are extinct, we're not that special.

We're pretty special, at least in the context of this planet. Science tells us that we are by far the most intelligent creatures to live on Earth in its observable history, and the only ones to meaningfully modify it.

In the very least, we are the only creatures to inhabit Earth, that if we become extinct, it is somewhat likely that we are both the victim and the perpetrator.

> and the only ones to meaningfully modify it.

The first oxygen-excreting algae may have a prior claim...

I'm not sure this is relevant. I mean, yes, they most certainly changed the planet itself, but it wasn't really to benefit themselves, was it? We build skyscrapers and Howitzers for intentional purposes, not because we excrete them.

> but it wasn't really to benefit themselves, was it?

Well, their descendants are pretty much everywhere you see something greenish, so it seems to have worked out.

> We build skyscrapers and Howitzers for intentional purposes, not because we excrete them.

We also emit pollution for intentional purposes. They might not be particularly noble purposes, but they're 100% intentional by each of humanity's individual parts.

I think you're confusing "the tools we use" versus "the ways we change the globe". Most of the worldwide changes we cause are not explicitly planned or built, but side-effects of the "metabolism" of our civilization.

Cyano-bacteria created our current breathable atmosphere and most all iron deposits. Calciferous phytoplankton built England, vast tracks of southern France and literally creates the air we breathe. Those things all meaningfully modified it back in deep time and continue to modify it today.

Intelligence is not a indicator of survivability, and if it somehow was, we found ourselves on the completely wrong side of the argument. How many other planet-altering intelligent species do you see around you ? Do you think that is a good indicator of survivability ?

This seems fallacious, but I can't put my finger on how. Yes, there is currently a lack of "planet-altering intelligent species," but, as far as we can tell, there has always been a lack of planet-altering intelligent species. We don't have any evidence of a being with human-level capabilities than then died out.

Surely not the only ones to meaningfully modify earth. If you look from space, earth looks green... Also, wasn't the atmosphere changed to be more rich in oxygen by early microbes?

We're hoping to start a colony on Mars. How could we possibly make Earth even remotely as inhospitable as Mars? Do you expect us to remove all the oceans' water? Remove most of the oxygen from the atmosphere? Kill all plants? I don't think we have much hope of making Earth inhospitable to us even if we tried.

Perhaps we somehow contaminate it all with nuclear waste. Even then, there'll be safety underground for long term living, relative safety even in contaminated areas for short term work, and radioactive water can be cleaned by distillation, mechanical or chemical means. We might have to set up a lot of infrastructure to do all that, but we've done a good job of setting up far more complex infrastructure already. It took only a couple of hundred years since the beginning of powered machines to get to where we are now. We could do it all again many times over in the next 10,000 years.

"Keep Earth hospitable" and "Colonize Mars" have very different goals, though. It would likely be humanity's crowning achievement to put a permanent outpost on another planet, but it would be, what, 15 people maybe? The other planet we're talking about has to support at least 7 billion.

I'm so old I remember we only supported 4 billion people.

Even pessimistically over one human lifetime I bet that "15 people" turns into at least 30.

You get gene pool and interbreeding issues with too small of a pool, then again you'd be amazed what you can store in liq nitrogen for a long time.

Also looking at the temporary and limited mineral and energy requirements, the earth isn't going to support 7B or 9B or even 1B for much longer, on a geologic / radiation timescale.

For awhile you can turn mined petrochemicals and chemical fertilizers into lots of human biomass. The key is for awhile, temporarily.

It's amazing to think the earth's population doubled between 1960 and 2000

Perhaps they are extinct because we've been erasing them as we reformat the earth to be more congenial to ourselves? Their extinction is not a signal that we may go extinct ourselves; just the opposite.

Mesopotamian Ziggurat, Teppe Sialk, dates from around 2900BC (~5000 yo). Gobekli Tepe 12,000 years old?

The 99.9% has nothing to do with humans. He was probably referring to this:

https://en.wikipedia.org/wiki/Extinction_event#Major_extinct...

Yes, pretty much the result of the 5 major (or 9 major) extinction events. I was using this [1] it's a number frequently used when referring to whats been and whats left. It's really an extraordinary number when thinking about it.

[1] http://www.pbs.org/wgbh/evolution/extinction/massext/stateme...

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