4th-gen reactors will eat current nuclear waste and spit out waste that is significantly less radioactive.

geo: that is because you are thinking in plutonium waste product terms, some fourth gen nuke plants would just gobble that stuff up and say 'moar plz!' take the thorium cycle, waste products have a half life of...a few hundred years, sure it's pretty hot during that time, but it cools a hell of a lot faster and just for kicks it has a lot LESS waste, under 1 percent if i recall correctly.

in other words a few dozen of those nifty plants will gobble up all the waste produced in the rest of the worlds old plants and consuming the waste deposits, given a reasonably sustainable rate the 'long term deposits' would be LESS utilized and shrinking, assuming that kind of use is approved, which it would not because green nuts would scream 'they are using filthy fuel the output must be even worse!' fucking greenie morons.

and as a side note, even the current nuke plants are a hell of a lot cleaner(as far as environmental impact is concerned, assuming a well run plant that follows disposal laws.) compared to coal or hydrocarbon burning plants without a doubt, water plants do not produce any visible waste but they destroy entire ecosystems by their placement, would not surprise me at all if wind power has similar large scale problems probably causes weather pattern changes, or as it has been said before, there are no free dinners.


bottom line on this subject can be summed up by a nice quote about science vs religion.
'a good believer disregards observable fact, a good scientist disregards things that do not have basis in observable fact, which of these two groups do greenies generally fall under?'

I remember watching something on the history channel once where they were talking about green tech, and one power company (I think its in the Arizona desert or something) came up with a brilliant idea. When using natural gas as a power fuel, they wood feed the carbon gases through a series of tubes that were filled with water and would grow algae in it. The Algae take in the carbon, exhale oxygen, and when you make enough you can harvest it. You can use the plant for paper, or an petroleum alternative for plastic or fuel.

You can also use the protein as food, and the sugars to create alcohol, but currently the technology is restrained by the difficulty of breaking the algae into it's component parts.

Some people cite the proliferation hazard, but restricting civil nuclear power won't do much about proliferation. In the first place, how exactly is the US opening and running more nuclear power plants going to encourage other countries to get nuclear weapons? And how is reprocessing of spent fuel (which, for PWR fuel, produces plutonium that isn't suitable for weapons use anyway) going to do the same, either, or be a security risk, especially considering that the US already has several thousand nuclear warheads and associated delivery systems, not to mention the hundred-odd MT of plutonium produced during the Cold War?

The point is that the nuclear technology and nuclear weapons genie is out of the bottle. The US no longer has a monopoly on this very useful and powerful technology - plenty of other countries can and will build and export competent power reactors. And nuclear weapons - well, proliferation is a bit hard, from a technical standpoint. Some people oppose SILEX (a laser enrichment technology) because they say it's simply too good - terrorists could conceivably build an enrichment plant and process a bunch of uranium and build a nuclear warhead. This is ridiculous. Terrorists will never develop and manufacture their own nuclear weapons, for the same reason terrorists don't go out and build shipyards to produce aircraft carriers and submarines. For states, though, it's relatively easy at this point, and there's not much that can be done to stop a state determined to acquire nuclear weapons. The US did it for the first time in the 1940s with laughably primitive technology and a very simple reactor - using slide rules, they designed what was essentially a giant block of graphite that had a bunch of tubes in it. The North Koreans and Pakistanis were able to do it, and the Iranians might well be doing it now. (It's not as clear-cut as some people claim.) If they can do it, anyone can.

actually fourth gen plants, fast reactors and lftr's most of them CAN'T be used to create weapons grade fissile material(the main reason those basic designs were utterly disregarded in the first place, no military funding.) you could make dirty bombs i suppose, conventional explosives with radioactive material to salt the earth....but not atomic bombs.

So what you're saying is there's way less nuclear waste, but tremendeously more radioactive to begin with.
Since the initial radioation level is way higher, a half life of a couple centuries brings that down to perhaps the typical radioactive level of <4th generation plants waste?
Still, this means you need a storage solution which will hold (no leakage and stuff) for the better part of a millennium (after all, half-live doesn't mean it has "cooled" to background radiation levels), which is today still not achievable.
Not to mention, that means even more intensive nuclear waste has to cross (likely heavily) populated areas to reach their storage sites. Don't know if you would like to have a nuclear waste transport pass by your home on a seasonal basis.

I didn't mean the fourth-gen reactors when I mentioned proliferation hazard. Incidentally, you could use them to produce weapons material, but you'd need to make significant design changes - I mean, you do get a nice neutron flux. Just put in a way to stick targets in there somehow, cool them, and swap them out on a frequent basis. But then you basically have two reactors in one - think about it, you'll see.

Incidentally, it's very simple, especially today, to build plutonium production reactors suitable for a weapons program. The US did it, with laughably primitive means by today's standards, in the 1940s. The Pakistanis and North Koreans were able to do it. Remember, the B Reactor was just a block of graphite with holes - channels for control rods and for the fuel elements, which were cooled by the water flowing around and past them in their channels - drilled in it, housed in a big concrete building. Any half-decent construction company (although you'd need a pretty big one) could handle most of the plant construction, and some physics undergraduates with their laptops, pirated CAD software and neutronics codes (not to mention MATLAB and Mathematica) could do it.

As far as nuclear waste goes, well - it isn't really a problem. The quantity produced even by current power reactors is minuscule, at least considering how much energy you get out of it. Fifty years of civil nuclear power generation in the US have produced enough spent fuel to cover a football field to the height of the goalposts. Not only that, but the waste is solid and stays relatively put. And you can actually begin to talk about entombing it for all time beneath the earth.

Incidentally, if you chemically reprocess spent fuel to get more plutonium, you don't increase the quantity of radioactive materials, or at least the useless, really hazardous-to-transport ones. Say you have a quantity of spent fuel and you separate it out, getting rid of some of the nasty fission products - well, if you look at the materials you have afterwards (although I guess they've decayed a little) you have the same amount of radioactivity as you had before. But now the really nasty stuff is concentrated and compact.

As far as having SNF transports and the like go by your house, if you live near a rail line chances are worst stuff goes past every day. Tanker cars full of poisonous gasses, let's say - chlorine and the like. Spent nuclear fuel and other radioactive materials, though, are housed in great big rugged casks and are solid and dense to begin with.

More tomorrow. It's 0153 here and I'm tired.

Well maybe we could put the waste in the North Dakota Slag pits which will arise from the shale oil operations. I mean it's just going to be one giant superfund site anyways.

We could build the pyramids, or the Colossus of Rhodes, or the Parthenon, etc., today if we really wanted to. The idea of a massive protective structure in a non-faulting zone (Nevada was a HORRIBLE choice) to protect an internal liquid-shedding structure made of inert materials does not strike me as THAT difficult an issue. Simply design the thing to keep mechanical stresses away from the structures that protect against chemical stresses, and build it big enough to last.

I'd start with very deep mining operations, myself. Especially mining operations that were used to produce radioactives in the first place.

Frankly though, I favor reprocessing first. Populations are becoming more concentrated all the time, which means that you can centralize things all the time. Sooner or later, population density + superconductors will reach the point where nuclear complexes can themselves be concentrated, including a on-site breeder reactor (though probably a weak one). This allows security to be strengthened (if there's real concern, then just mandate such in law), while simultaneously shortening the half-life of the radioactive material (which is, after all, how fission reactors work in the first place).

I don't know where you get your information, but that's not how shale fracking works.

Slag heaps are a product of conventional mining operations. They're the cast-off material that was either removed from the desired material, or removed to get to the desired material. E.g. a gold mining operation would have slag that surrounded the gold ore, and slag from the refining process, the later of which might be contaminated with mercury.

Fracking is a drilling procedure. They drill a vertical hole, then have the drill start drilling horizontally into the shale (yes, they can do that). Then they send a custom designed gun down the hole, where it shoots holes along the shale. Then they remove the gun, force water down the hole with tremendous force so that the shale fractures near the hole (this is where the process gets the name 'fracking'), and have the water carry sand into those fractures to hold them open after the water has been removed.

The amount of waste material removed from shale oil & shale gas operations is very small. Were it otherwise, they likely would never have started using shale. The concerns about pollution from shale are:
1) Those related to all oil & gas wells,
2) Ground-water contamination concerns (very rare, the ground water is usually VERY far above the shale), and
3) Air, soil, & surface water contamination from the water that's been removed from the well (specifically the additives).

In short, we can't hide much of anything in shale mining slag, because there isn't much to hide it in.

The first time I saw shale oil extraction was up in Canada about 10 years back. Open pit mining operation with huge trucks which take the stuff to these giant grinders...

"Shale oil extraction is usually performed above ground (ex situ processing) by mining the oil shale and then treating it in processing facilities. Other modern technologies perform the processing underground (on-site or in situ processing) by applying heat and extracting the oil via oil wells." From the most reliable source http://en.wikipedia.org/wiki/Shale_oil_extraction

So all in all, North Dakota will still have plenty of open pits/super fund sites which can then in turn be made in to super-super fund sites through the disposal of radioactive waste.

A 1000 years is much better the the 10,000+ years for the existing waste products. As I understand it, the problem isn't a mechanical one. We can design and build a containment system that will last for 10,000 years. The problem that is worrying designers is human activity. At 10,000 years it is hard to imagine what human society would look like, therefor virtually impossible to craft an understandable warning message for it. Nor could we be assured that our warnings have passed through history intact.

So to recap. Future humans may not know that disturbing the site is bad. We have no reliable way of communicating to our descendants that disturbing this site is bad. And finally there is no way to design a containment system that will defeat a human determined to get inside.


This doesn't mean that there will be more frequent transports of waste. We have on-site storage solutions that will work for 50 or more years. More likely waste would be stored on site until the power plant is decommissioned, then moved once to permanent storage.

I have no awareness of this technique being used en-mass. Also, to the best of my knowledge, large numbers of drillers are being hired for the N./S. Dakota operations, which implies drilling. How thoroughly have you checked into this? Open pit mining is only used when you want something close to the surface, because otherwise you have to move too much material that's on top.

Worse, as certain Republicans (and some less-than-realistic business people) show, there are those who view any limit to blindly charging into situations that they never predicted to be unacceptable.

Consider the reaction that these people would have to the idea of deadly poisons being stored in their way: "That's ridiculous, this is obstruction!".

Our descendants a hundred centuries hence damn well better not be a bunch of primitives who don't know about radiological hazards.

At any rate, honestly - in ten thousand years we'll all be dust. We might well all be extinct or unrecognizable by then. So tell me why exactly we're going to all this trouble, especially to the extent that we might be giving up a very attractive source of power, for the sake of some people that, in ten thousand years time, may or may not live to have some trouble with some of the waste products? Chances are that if they don't know about radiological hazards there won't be very many of them anyway. And there will be worse dangers facing them than fission products by then, probably. I'm sure some people will say that it's some kind of ethical obligation on our part, but I think it's a real stretch and based on pretty specious reasoning anyway. We should make damn well sure our descendants ten thousand years hence will be successfully carrying on the mantle of our technological civilization, not a bunch of hunter-gatherers. As I said, they'll probably have more to fear from volcanoes and earthquakes and so on.

Besides which, many of the proposed long-term geological storage schemes involve putting the waste somewhere rather inaccessible - sealed up inside a mountain, or under the better part of a kilometer of rock, again quite well sealed-up, and then stored inside a cask for good measure. This would imply a very high degree of engineering knowledge to access, which sort of invalidates the protecting-future-primitives argument.

So, uh - someone convince me that we have some ethical obligation to account for that outlandish, though oft-cited, scenario.

Next - and I think this is what the French do - not only does reprocessing of spent fuel from light-water reactors (PWRs and BWRs) stretch your supply, but I'm pretty sure you end up separating out all the hazardous fission products from the useful material, which you can make into new fuel elements. As I recall, it's possible to vitrify that - you turn it into a glassy substance, a kind of synthetic rock. And that's stable forever, and quite compact. Here is a link to a news article related to it - they discuss the details of the process in passing. They mention a glass matrix - presumably they take the nasty stuff in particle form and make a composite with it, with particles of the residues from reprocessing embedded in glass.

But anyway - let's discuss something else. What should we actually do?

I'd say step up construction of advanced light-water reactors (PWRs and BWRs) in the near term - ten to twenty years. A high build rate is quite possible - look at what the USN managed, as did the US and several other countries. Those were pretty good reactors, too - many of those civilian US designs were very conservatively designed, and so they ended up being sufficiently overbuilt that they're getting life extensions. In the longer term, go to LFTRs.

If you're interested about waste management and LFTRs, well - has anyone detailed the LFTR fuel cycle in this thread yet? Well, it can't hurt to reiterate. LFTRs transmute Th-232 into U-233 and burn Th-232. The coolant is a molten salt - a mix of lithium and beryllium fluorides, called FLiBe. The Th-232 and U-233 are dissolved in the FLiBe, as fluoride salts. Everything's in a liquid state. I think with both a single fluid and a dual-fluid LFTR you have a reprocessing plant that continually filters out certain species from the coolant loop. For instance, when you transmute the Th-232 to U-233, one of the steps in the decay chain lasts several days - there's some time where the nucleus that began as a Th-232 nucleus is some Np (?) isotope and you don't want it exposed to any neutrons, so you filter out one of the species intermediate between the Th-232 and that Np species and let it undergo the decay elsewhere before you reintroduce it, once it becomes U-233. Wikipedia says you get 800 kg of (very dense) waste per gigawatt-year. That's not very much.

I don't share your confidence that such a containment system can be implemented for such a long time.
As far as I know, there's nothing much in the pipeline beyond "put it in thick barrels and store it in a deep salt mine" or something like that.

I could but my solution involves the sun and had a far longer safety period <_<

Oh, you would launch nuclear waste in orbit, and put it on a sun-intercepting trajectory?
What was the failure rate of orbital launches again?

Anyway, the sun is a terrible option. Use the moon instead, much less energy to get there. Added bonus of it being just a rock instead of eventually radiating it all back to us.

Dig a hole and dump it in is still the best option though.

A long while back I saw a comedian on TV who, as part of his routine, mentioned the nuclear waste problem. He suggested giving all Americans an approximately key-sized piece of waste (probably he meant spent fuel) and then just having them lose it somewhere. While that would be a bad idea, he unintentionally got the math about right - that's about the mass of spent fuel that would be produced per capita if all the electricity generated in the US was nuclear.

Anyway - the spent fuel is still mostly similar to what it originally was, and contains a higher percentage of U-235 than natural uranium. It really is a waste not to reprocess it. Once again, reprocessing is chemical - if you have some quantity of spent fuel and you reprocess it and separate it into its component substances, you won't have any more radioactivity in it than what you had going in. You can reuse the useful stuff, and now the hazardous/dangerous stuff is much more compact. You could convert it into a more stable form. The French currently reprocess and vitrify, for instance.

less energy? SERIOUSLY? you actually have to AIM to hit the moon, while a shot at the sun requires is quite literally any form of decaying orbit... and it happens to land on Venus there are no problems either, and the odds of it getting gravitationally sling-shot back from the same isn't much of an issue assuming you are chucking around low size lumps (say 100 kilos) as it wouldn't even manage to hit the ground before it finished burning up.

Edit: Actually I have a longer term solution... you remember the Lagrange points?
Stable orbit locations away from the planet with little likelihood of disruption :p
I'd still feel safer with them in the sun, while the moon is somewhat more likely to be colonised.

Lucky us, 1999 has already passed.



Yeah, part of that reprocessed fuel passes through my country on its way to our nuclear plants... by train.



There's only two really long-term "stable" Lagrange points: L4 and L5. I don't know if you follow space news, but the astro-scientific community is fond of Lagrange spots too for obvious reasons. They put deep-space observation platforms there for those kinds of research by which an Earth orbit is disruptive for the instruments sensitivity, or to have permanent shadow or something. Sofar, L4 and L5 of the Earth-Moon system are not in use, but they're kind of obvious spots for industrial stations (if those ever get off the ground).

geo: the numbers i have on waste for the new plants is well UNDER 1000 years.

besides if the 'waste' was allowed to be reprocessed close to 90% of even the current waste could be reused in new fuel.

You could probably just impact the waste into the moon if you wanted. It takes much less energy to do that than to put something on a trajectory towards the Sun, trust me. Orbital mechanics.

Let's see...for Earth, mu is 398600 km^3/s^2, for the Moon it's 4917, and for the Sun it's 132712440018. The Moon orbits at a mean radius of 384000 km from the Earth. Let's say you start out in LEO, in a 200-km altitude circular orbit - it's basically sufficient to make a burn to expand your orbit into a highly eccentric elliptical one that takes you into the neighborhood of the Moon at apogee. It's not very hard to aim, actually - the Moon has gravity and will capture you if you time the burn right. So - your initial radius is 6578 km, with e = 0. You want to go into a 200 km by 384000 km orbit. You end up with e = 0.998 - the semi-major axis is 192100 km. This means you have a specific orbital energy of -1.037 km^2/s^2 - by comparison, if you're in LEO, your specific orbital energy is in the neighborhood of -30 km^3/s^2. This trajectory will see you crashing into the Moon. Now, how much delta-V do you need? Well - assuming it's an impulsive burn (finite burn is a pain in the ass) you need about 3.2 km/s. The Apollo TLIs required about that much.

Now, escaping outright from the Earth's gravity and then deorbiting an object into the Sun? Well, let's see here...once you've left the Earth's SOI (we're using patched conics here) you need to end up with a periapsis inside the Sun, let's say. That's 6.955*10^8 - let's say 6*10^8 will do. The Earth is 1 AU out - 1.44*10^11. So, your e = 0.9917. This makes your semi-major axis 7.225*10^10 m - about half an AU. That makes your SOI -0.92 km^2/s^2. At your apoapsis, you need to have a velocity of more or less 0 km/s to the Sun. But the Earth is traveling 30 km/s relative to the Sun on average. So, you need to make a burn that'll have you traveling 30 km/s relative to the Earth as you get far away from it. Now, this takes a lot of energy. Neglecting a lot of stuff (i.e. velocity components and so on - this is very simplified) you'll need to make about a 24 km/s burn from LEO to do that. It'll actually be more, I think.

Now, tell me - is it easier to get into LEO and then make a 3.2 km/s burn or a 24 km/s burn?

I don't have to ELIMINATE all the 30km/s once in orbit.

You can just shoot backwards and the velocity required to penetrate the earths gravitational field will be deducted with relation to the sun in the first place thus imparting a different kinetic energy in the first place.
You still have to break the gravitational grip, but that isn't all that hard.

Additionally a nice curving spiral decay orbit doesn't even require that we remove more than 1 km/h according to my understanding.
personally I would rather have a nice spiral that would miss the earth when we return next year, but that is because planets are not point objects in space, although they are somewhat similar.

One sensible point is that a sun launch system could benefit from the use of a rail-gun launch system... and you could use it every single day for quite a few hours to achieve your desired path. (I believe there would be a 3-4 hour opening, only 1/6th of a day.)
The moon also offers a daily target, however it is a very small sweet spot in the sky requiring rocketry and manoeuvring thrusters to ensure a decent hit.

Not to mention 1000 years ago we were starving, and believed god was everything we needed to live and survive.
These days we normally use medicine and hope god will help us get through the day.
In 1000 years I do not want my descendants complaining about the radioactive chunks we threw at the moon in the hope it would be rid of them eternally.

Also: L4 and L5 look great right?
Except they are 'peaks' in the gravitational system, any movement away from your desired point will lead to destabilising their positioning.
Manoeuvring thrusters will be required, Batteries not included.

No, you do have to do that. Orbital mechanics is pretty strict. Again, based on the patched-conic approximation (which is a good approximation) you need a lot of delta-V to end up in the Sun. Again, if you look at the sort of trajectory that an object headed into the sun would travel (a very eccentric elliptical one) you can figure out the required velocity at the apses.

The calculations I made were based on going backwards in the first place - the Earth travels about 30 km/s relative to the Sun, so you need to, one way or another, get rid of most of that 30 km/s tro end up plunging into the sun. Escaping from the Earth so that you're on a retrograde trajectory (that is, the Earth appears to end up outrunning you) is the cheapest way to do it.

I'm not so sure about the low-thrust trajectories, but 1 km/s is waaaay too low. It also takes a long time and you need pretty good electric thrusters to do it.

Bottom line: orbital mechanics does not work that way!