[Geezer (OP)]

Yes let's get back to the original idea...
It's a terrible one!

Right. New topic!


I think the main problem is it's bloody heavy stuff and there's more than a fading chance of a problem a launch.

Look buster - there's only room for one anecdotal physicist around here.

Yes, there could be a launch problem, but you're just using that as an excuse for not doing the math.

[peppercorn]

Okay. Fair enough! Now where did I put that slide rule .... *goes off to route in drawers*....

[Geezer (OP)]

Surely it can't be so difficult to work this out.

How about we determine the amount of work done to elevate a mass far enough above the Earth's surface that it starts to fall towards the Sun, rather than back to Earth? No orbits or fancy trajectories required.

[syhprum]

Bodies don't start to fall towards the Sun they retain the orbital energy associated with their orbit around the Sun that has to be removed in some way.
There is no friction in their environment they have to be imparted with an acceleration of 30M/s from some source.

[Geezer (OP)]

Bodies don't start to fall towards the Sun they retain the orbital energy associated with their orbit around the Sun that has to be removed in some way.
There is no friction in their environment they have to be imparted with an acceleration of 30M/s from some source.

Ah! Good point. So we'd have to include the work required to achieve that deceleration of the mass, or it would just stay remain in orbit around the Sun.

[CliffordK]

Sorry about heading astray,
But I do believe before shooting stuff into space, it needs to be reduced to the absolute minimum amount possible.  Pull out all the fissionable isotopes and the non-radioactive "Rare Earth Elements".  Then consider if there are enough long-lived isotopes left to justify the program.

As far as orbital insertion.
Isn't there a number of different approach angles.
If one aims dead center for the sun, it should plow straight in without worrying about a decaying orbit.  One just needs to aim right.

I certainly don't want a proliferation of radioactive space junk in unstable orbits around any object in our solar system. [xx(]

2 Major Shuttle Accidents should serve as a reminder of the dangers of a space program.

Wikipedia has a list of Space Accidents, although I'm not sure if non-fatal accidents are listed.
http://en.wikipedia.org/wiki/Space_accidents_and_incidents

If the Shuttle Challenger had been carrying a few tons of nuclear waste, it could have been a disaster of epic proportions with waste both airborne and scattered through the Atlantic.

Certainly there are multiple nuclear waste streams.  There are enormous amounts of low level waste.  I was on a project that was digging up and shipping about 10 railcars full of low level waste a day to southern Idaho.  And anything that touches it becomes low level waste too.  The only thing that would be at all economical to "export" to space would be the high level waste, and even that would necessarily need to be reprocessed which might eliminate the problem.

[Geezer (OP)]

Yes, but how much energy would it take to get rid of the stuff? If it takes more energy to get rid of it than the energy energy it produced in the first place, it would not only be dangerous, but pointless.

[CliffordK]

How about some numbers.

For the Saturn V
3,039,000 kg total loaded weight (I think).  Oxygen, Hydrogen, Aluminum, whatever (about 90% fuel, 10% being structure).
45,000 kg payload to Trans Lunar Injection.  I assume a bit more for a longer voyage, for example towards Venus.
http://en.wikipedia.org/wiki/Saturn_V

Anyway, that gives about a 1:100 payload/rocket mass ratio.

If very little of the rocket is recovered, then one can consider essentially everything in it as "fuel".

Ok, let's look at energy from Uranium:

1 ton of Uranium gives about    7.4 x 10¹⁶ Joules.
1 ton of Coal gives about    3.2 x 10¹⁰ Joules.
http://www.phy.syr.edu/courses/modules/ENERGY/ENERGY_POLICY/tables.html
It takes about 300 kwh of electricity per pound of metal aluminum produced.
1 kWh = 3600000 J
Or, about 1 x 10⁹ Joules/pound aluminum.
(oops, on the order of 100 lbs coal / pound of aluminum, I think   [])

So, Uranium gives about 2 x 10⁶ times as much energy as coal, or 2,000,000 times as much energy than coal. 

So...
If it took 1000 tons of coal to blast 1 ton of uranium into space (production costs and etc).  You would still have a net energy surplus from using the Uranium.  But the actual value would quickly dwindle if you considered all the refining costs & etc.

Keep in mind that all fission byproducts are not the same.
As I mentioned, in the USA, only about 10% of the "new" nuclear fuel is burnt, and 90% remains.

According to Wikipedia, there are about 7 "Long-Lived" Nuclear waste isotopes with half-lives ranging from 200,000 years to 15 Million years, accounting for about 20% of the fission waste products.

http://en.wikipedia.org/wiki/Fission_product

Another 12% of the waste has half-lives of less than 90 years, and could likely be effectively managed on earth.

It would take more time than I have tonight to look at the entire decay chains of every product, what is fissionable, percentages, and etc.

Anyway, so, if effectively separated, and reburnt, only about 20% of the original reactants would need to be disposed of in a "permanent" storage facility, and we would get about 10x the energy out that we are currently recovering.

It is still probably not economic as far as dollars and cents to ship this waste to space, but it certainly could be done.

Perhaps summing it up, it would take on the order of 0.1% of the energy produced to ship the high level, long life radioactive waste up into space.

There are discussions online of using other types of (pie in the sky) accelerators other than conventional rockets to make it more cost effective in the future.

[Geezer (OP)]

Yeahh!!

Numbers are good. Thanks Clifford.

[Geezer (OP)]

Does anyone know how much work would be required to lift 1 kg to L1 (Lagrangian point 1)? I understand it's around 1.5 million kilometers out.

[jartza]

60 megajoules

calculated by myself, from escape velocity 11 km/s, might be 10% off

[Geezer (OP)]

from escape velocity 11 km/s, might be 10% off

Are you sure? L1 is at a much greater height than the orbit for escape velocity.

[yor_on]

Heh, Then we could try to arrange them to pulsate too, and now and then explode "Hey, can you see us?" sort of. I know, it's not that much energy maybe but still, it should beat the fourth of July if you're close enough. and then we have all those colors 'strontium' and stuff

But seriously, if you really want to create nuclear waste I would suggest we put it in our city's, glassed in or whatever method we might find work. That would ensure that we never lost sight of them, and no, I'm not joking. That way we all would be deeply involved in keeping them from 'leaking'.