'Tree-sized' Nuclear Reactor to power rural Alaska houses, cars

[PeteH]

Sending the waste into space would be no problem, given the political will. There are designs for 9" thick steel containers which could easily withstand the worst-case re-entry and impact without spillage.

OK assuming that somehow you do muster the 'political will' to be the first to shoot large loads of nuclear waste into space, there are still several things which to me at least woudl qualify as 'problems':

How much do these 9" steel containers weigh, how much waste do they hold, and what is the reasonable cargo capacity per launch? I have a hard time believing that without near constant launches this woudl even put a dent in the stockpiles of waste looking for a home. Not to mention the costs of all those launches. I'm sure the thousands of gallons of fuel per launch will be wonderful for the atmosphere.

I guess what I don't understand from some of the big nuclear proponents (in general, not on the board specifically) is that at least a few of them are scientists, who in most other respects work with evidence, test hypothesis, etc. But when it comes to dealing with the consequences of nuclear power, they indulge in speculation and assume someone else will take care of it.

[Curiosity]

On the issue of cost - of course it depends on your assumptions. For projected future launch systems it's not too bad, for current systems it's obviously unacceptable. The equations change depending on how much you're allowed to reprocess the waste, which AFAIK is not currently allowed at all in the US.

One solution is a laser-launch system. It's the safest (with a chemical-launch system there is a trivial risk of an explosion placing the container on an earth-intersecting elliptical orbit, which would be enough to rupture the capsule. Of course you can always nuke it, if that did happen. ) and probably cheapest in the long term, with launch costs around $100 a pound to solar escape velocity; plus you get to use it for other things, like space settlement. It uses electricity for power, which we can generate using nuclear sources, so it has minimal greenhouse implications.
Unfortunately someone has to stump up $20 billion in the first place to build the launch array.

Anyway; a short answer, given reasonable assumptions for an advanced launch system, is that it will cost about twice as much as burying the stuff in the ground. Even using rockets the greenhouse gases released will be trivial in comparison to what is saved by using nuclear power.

It's something I'd be in favour of mainly because it might lead to someone developing a cheap launch system but it is not a technical problem if you are that paranoid.



I guess the reason why engineers are so blase about the whole problem is that it doesn't look all that hard. The egyptians managed to build structures which kept their contents dry and isolated for 3,000 years. Why the heck should anyone imagine that we can't do it? In three thousand years we should have the tech to solve any problems which remain, or be dead. In either case it's irrelevant.

[Sikander]

Originally posted by Curiosity
On the issue of cost - of course it depends on your assumptions. For projected future launch systems it's not too bad, for current systems it's obviously unacceptable. The equations change depending on how much you're allowed to reprocess the waste, which AFAIK is not currently allowed at all in the US.

One solution is a laser-launch system. It's the safest (with a chemical-launch system there is a trivial risk of an explosion placing the container on an earth-intersecting elliptical orbit, which would be enough to rupture the capsule. Of course you can always nuke it, if that did happen. ) and probably cheapest in the long term, with launch costs around $100 a pound to solar escape velocity; plus you get to use it for other things, like space settlement. It uses electricity for power, which we can generate using nuclear sources, so it has minimal greenhouse implications.
Unfortunately someone has to stump up $20 billion in the first place to build the launch array.

Anyway; a short answer, given reasonable assumptions for an advanced launch system, is that it will cost about twice as much as burying the stuff in the ground. Even using rockets the greenhouse gases released will be trivial in comparison to what is saved by using nuclear power.

It's something I'd be in favour of mainly because it might lead to someone developing a cheap launch system but it is not a technical problem if you are that paranoid.



I guess the reason why engineers are so blase about the whole problem is that it doesn't look all that hard. The egyptians managed to build structures which kept their contents dry and isolated for 3,000 years. Why the heck should anyone imagine that we can't do it? In three thousand years we should have the tech to solve any problems which remain, or be dead. In either case it's irrelevant.

What's a laser launch system?

[Urban Ranger]

My gusess is sending something up by light pressure.

[The Mad Monk]

Originally posted by Sikander
We wouldn't necessarily need to use rockets to launch nuclear waste into space. We could use mass drivers that could be much more reliable, as there is no reason to avoid very heavy g forces. The loads could then be picked up in orbit and placed into an even larger (but much more efficient due to the lack of air resistance) mass driver and propelled into the sun.

Given the rate at which we find new uses for old crap, I'd be leery about shooting anything into space (or any other irretreivable disposal method, for that matter), as we might need it later.

[axi]

A huge body of water will not give you the concentration needed.

Bad phrasing. I was thinking more in terms of critical mass. Low concentration means a much largermass of uranium in water solution in order to go critical.

[Kuciwalker]

Originally posted by axi
skywalker. I can see a few problems in your idea:

1. Density. Uranium concentration in water would never reach the critical stage, unless a huge body of water were used.

2. Vapour contamination. Solids vaporize too, so during decompression, some of radioactive material would exit the system along with the water vapour.

3. Byproduct separation. During nuclear fission, Uranium nuclei are split into two smaller radioactive nuclei (don't remember the element's names) which, inside a spent rod, are incorporated into the same metal matrix as the original material. These byproducts will probably crystallize in a similar fashion together with Uranium in the residue that is found after the vaporization of the solvent. So your goal of separating spent material will not be achieved. Apart from that, even if you achieve separation (by processing spent rods, as North Korea is doing f.e.), you will still have to dispense of the two fission byproducts in some way.

One good solution to help with the radioactivw waste storage problem is to include radioactive materials as cramatic elements in glass. All heavy metals are good cramatic materials for glass. F.e., the most important ingredient for all high quality crystalware is led. DU specifically is being used in some crystalware processes because it makes crystal fluorescent under UV light. The good thing about inclusion in a glass mass, is that it virtually eliminates the probability of leakage, because glass, unlike pure metals, does not corrode.

It was just an idle thought, anyway

Anyway, the idea wasn't so much to eliminate nuclear waste as to stop wasting so much nuclear fuel. I remember reading an article that said a nuclear fuel rod was "spent" once it was at something like 95% or 98% of its original uranium content.

[Kuciwalker]

Originally posted by Sikander
We wouldn't necessarily need to use rockets to launch nuclear waste into space. We could use mass drivers that could be much more reliable, as there is no reason to avoid very heavy g forces. The loads could then be picked up in orbit and placed into an even larger (but much more efficient due to the lack of air resistance) mass driver and propelled into the sun.

It's not whether you use a rocket, a railgun, whatever, the fact is you need AT LEAST a certain amount of energy to get out of earth's gravity well, and for something as dense as uranium, that amount is extremely large.

[mrmitchell]

The egyptians managed to build structures which kept their contents dry and isolated for 3,000 years.

Surely you don't include all the grave robbers and tomb thiefs that snuck in and stole all the loot?

[Dis]

who would want to steal nuclear material?

[Sikander]

Originally posted by skywalker
It's not whether you use a rocket, a railgun, whatever, the fact is you need AT LEAST a certain amount of energy to get out of earth's gravity well, and for something as dense as uranium, that amount is extremely large.

Wrong insofar as the issues I'm addressing are safety and the environmental impact and economy. Rail guns use electricity, which we are going to make with nuclear power, thus avoiding the vast bulk of the greenhouse gasses, as well as saving a ton of money on rocket fuel and rocket launches. This system would be pretty damned simple (several orders of magnitude simpler than launching a rocket IMO), which would make it a lot safer than launching stuff with rockets. The only reason that we use rockets now is that the satellites and astronauts we send up would be destroyed by the g forces that a rail gun would generate. We don't need to worry about wrecking nuclear waste in the same manner.

[:) Smiley]

Funny how with nuclear power people are so worried about the byproducts, yet seem to ignore that big sulfurous cloud belching out of the coal plant.

[The Mad Monk]

Do any of you have any idea how rare this stuff is?

If we dump it into the sun and extraterrestrial civilizations catch wind of it, we'll be the laughingstocks of the galaxy!

[axi]

Funny how with nuclear power people are so worried about the byproducts, yet seem to ignore that big sulfurous cloud belching out of the coal plant.

That cloud IS big, but it shouldn't be sulfurous, at least not in anycountry with proper environmental regulations. All coal plants have filters nowdays.

The funny thing is that coalplants are actually producing radioactive pollution. By digging up and burning coal, they release significant amounts of radon into the atmosphere.

[TCO]

there are still some decent amounts of SO2 getting into the air.

wrt the nuke:

1. The part about burns faster at same power, makes no sense.
2. you can't operate a system like that without operators for the steam system and the electrical system.
3. 100 MW is not a walk in the park, either...