Nuclear Waste

There are a few widely-cited problems with nuclear power. First, they're expensive. Second, their operation can be modified to help create nuclear weapons. Third, and perhaps most important for our purposes, they produce a lot of waste.

How much waste? Depends on how you look at it - most of the radioactive waste generated by the world is clothes, gloves, and rags used in the vicinity of radioactivity (including hospitals, refineries, and some factories, not just fission reactors). If we want to talk about the dangerous stuff, that's classified as high-level waste and transuranic waste - this is the stuff that reactors make and that we dispose of. We end up with about 12,000 metric tons of high-level waste a year, or, to use an analogy, 100 double-decker buses worth. And more of the transuranic stuff, which is just designated as anything dangerously radioactive that takes a really long time to decay.

So why does waste even exist?? If you watched the introductory video I posted a week or so back, it says that a neutron splits a uranium atom (or, as we'll see, an atom of something else) and creates energy and... stuff. There's a lot of random stuff that nuclear reactions create - and, apparently, since they were born in radioactive fire, these molecules tend to be a little radioactive too.

So what makes it dangerous? Broadly speaking, if something is radioactive that just means it's unstable; over time, the atom spits out parts of itself, which can hit other things and do some damage. Each time an atom emits something, it changes - becoming another type of atom (which is usually more stable and therefore less radioactive. Which is fine - in fact, it's totally cool, yay alchemical transmutation!

But the stuff they spit out can hit things like your cells, or, more dangerously, the genes that are held inside your cells. Broadly speaking once again, radioactivity does not mix well with the things that make up your body.

And the biggest problem is that we don't really manage the radioactive waste all that well.

Some background on the reactor process, first. The easiest way to make some nuclear energy is to take some uranium and maybe some plutonium and bring it together. That's it, really - you have a nuclear reaction! In that sense, making a nuclear weapon isn't difficult - it's mostly getting the materials and forming it into a bomb that'll explode when you want (and not before).

The difficulty comes with controlling it and getting electricity out of it. Basically, you slow the reaction down by mixing other junk in with the uranium. In the process, some of your uranium splits apart, forming other stuff - and at a certain point, you've made too much stuff, and it's walling off the unsplit uranium.

In practical terms, in almost all US reactors, the vast majority (over 95%) of uranium is wasted. Along with the radioactive stuff created, all of this is dumped somewhere into it decays. Unfortunately for us, that takes billions of years - and because of the radioactivity, whatever container this stuff is in degrades. It's like nature is giving nuclear power the finger, really.

So, we've tried leaving it in ponds or empty fields until the damn steel containers degrade and the waste leaks into ground water and then all it is is cancer and lawsuits and blah blah blah - so it stands to reason that the US Government is always looking for the best way of disposing of this stuff. Right? I mean, right?

Apparently not, though, because the best method has been held up by economics and politics.

If you notice before, I said that "US reactors" waste 95% of their uranium. We're not the only ones with reactors - in fact, the large majority of, say, France's electricity is produced through nuclear power. This upsets some people, but the upshot is that they're better at it than we are - they reprocess their nuclear waste (by removing the stuff that got created in the first go), re-use it, and end up using almost all the uranium they have.

So why don't we reprocess waste? President Carter said we couldn't, as part of his policies on nuclear proliferation [more on that in a future post], and by the time Reagan said we could, building new nuclear power infrastructure had stopped because of cost/environmental concerns. Irony?

Of course, once the uranium is all used up, the French (and other reprocessing countries) still have to deal with the other radioactive stuff - radioactive elements that can't be burned up for energy in a conventional nuclear reactor. That's where the second part of the cleaner nuclear power system comes in - fast reactors.

Fast reactors are, essentially, a nuclear reactor on speed - it doesn't try to control the nuclear reaction so much as supervise it, and because they throw out so many stray neutrons, they're capable of converting other heavy radioactive elements to fission power. It's great! And they're safer than I make them sound, too - France has one that's doing exactly this, and Japan has one and is building several more. (Of course, there's a small problem in that they use liquid sodium as a coolant, which tends to burn when mixed with water or air, but there are engineering ways around this.)

So how effective is it? They manage to reduce their waste by about a third, which isn't bad. In terms of theoretical technology, more efficient fast reactors would be able to reprocess and burn almost all fuel - it's just that no one wants to build them.

Short of re-using nuclear fuel, the other options are either storing it on Earth somewhere or shooting it up into space. Right now, shooting it into space is essentially off the table, because rockets explode occasionally and if that rocket were carrying a huge dirty bomb then that would suck for us, below it. So until we figure out how to either launch spaceships with lasers or build a space elevator (which we should totally do, not that it'll happen soon), space is outta reach.

So Earth it is. Where?

Dropping it into the ocean is somewhat dangerous (currents can disperse it all over the place) and illegal, so that's out (except for a special case I'll get to). Sticking it in the ground somewhere seems to be the next best option, except for the cost (of finding and building a site) and another weird little problem.

Some nuclear fuels take literally millions of years to become safe to be around. Setting aside cost and the fact that we can't guarantee any containers for millions of years - what happens if someone stumbles onto it in a million years? Who will that someone be, what language will they speak, what level of scientific know-how will they have - will they even be human? How do we warn them?

It's a little strange that this is a problem, given how much forward-thinking worrying about it requires, but it is.

But are there other options? Why, sure!

So Earth has this thing called plate tectonics, right? In some places, new materials are coming up from underneath the crust, solidifying, and pushing plates apart. In other places, though, material (aka seabed or land) is being pushed down under the crust through some process or another. So, some say, why not drop it into the center of Earth (slight exaggeration).

It's not a bad idea. After all, the reason we have plate tectonics 4 billion years after the Earth formed is because of all the radioactive junk (mostly uranium) knocking around in the core and mantle - its decay creates heat, which radiates around (and really confused 19th century geologists trying to figure out why the Earth was hot without knowing about radioactivity). There are still problems, though - not the least of which is simple philosophical; do we really want to build a society on literally shoving radiological materials under the rug of the Earth, out of sight? From another perspective, though, it is recycling, of a sort...

To get back on topic, though, the worst thing about nuclear waste is that nuclear power itself is politically charged and complicated. Doing things that might create weapons-grade uranium or plutonium are extremely frowned on, and is not technology that the "Free World" will up and give to a nation without nuclear weapons. That, in and of itself, spells trouble for any sort of wide-spread nuclear reprocessing ideas. Also, because of nuclear weapons, the Cold War, and perhaps Chernobyl, nuclear power on a whole has acquired a particular air of danger to it - and that makes changing the system much, much harder. Also, money (I keep dancing around this issue because I plan to devote an update to it).

So it's a problem. Insurmountable? No. But we've gotta start talking about it, internationally - something that seems to have been really stop-and-go since the Cold War ended.

And maybe, someday, we'll get a space elevator out of the deal.