Why the sun is a poor dumping ground for nuclear waste (2010) • Hacker News Board

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#151

Post by exDM69 » Tue, Apr 14, 2015, 7:59 AM UTC

dalke wrote: post #100

Terr_ wrote: post #90

Earlier quoted context omitted.

The sun's pretty big... And if you're worried about overshooting, you could probably lose a lot of velocity just braking against the solar wind.

While the solar wind gets stronger closer to the sun, it's an r-square law that balances the r-squared force of gravity. Fun fact: If a solar sail could be in a fixed position at Mercury orbit then it could also be in fixed position a Neptune orbit. Quoting from http://en.wikipedia.org/wiki/Solar_sail , the "total force exerted on an 800 by 800 meter solar sail, for example, is about 5 newtons (1.1 lbf) at Earth's di…

Your calculations seem sensible, but you're only talking about radial forces, ie. countering the "downward" force of gravity with "upward" thrust of a solar sail.

But space flight maneuvers typically use tangential or almost tangential thrust. Slowing down or accelerating the orbital motion will cause the altitude to vary, preserving the orbital energy and angular momentum. Placing a solar sail in a 45 degree angle from the sun will change the orbit slowly but surely, as there will be a little tangential and radial thrust.

I still don't think it's viable for throwing anything into the sun, though.

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#152

Post by nitin_flanker » Tue, Apr 14, 2015, 8:28 AM UTC

Could anyone here please explain why every time the rocket will return to Earth’s orbit and,the Earth won’t be there.

Does our solar system is constantly moving? Isn't it stationary with sun at center bending space and time and making planets to revolve around it?

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#153

Post by kitd » Tue, Apr 14, 2015, 8:42 AM UTC

parineum wrote: post #23

Even if it were actually difficult to get to the sun, there are other options that are nearly as effective. Jupiter would be just as good of a dump or we could just launch on an extra solar trajectory. Hell, we could just put it on a large, non-equatorial orbit around the Earth and it would be effectively gone with the added benefit of being able to recover it should we find a reason to. Space is a big enough place t…

Hey, Jovian here!

Sling yer 'ook and take your spent matchsticks with you!

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#154

Post by mahranch » Tue, Apr 14, 2015, 8:57 AM UTC

opo wrote: post #135

btilly wrote: post #110

Earlier quoted context omitted.

One of the downsides of reprocessing is that it makes plutonium easy to separate out in a form that is good for making nuclear bombs. Therefore it represents a nuclear proliferation risk.

None of the countries that have developed nuclear weapons have gotten their plutonium from nuclear waste because there are much easier ways to get weapons grade plutonium. Form the wikipedia page: "Ordinarily (in spent nuclear fuel), plutonium is reactor-grade plutonium. In addition to plutonium-239, which is highly suitable for building nuclear weapons, it contains large amounts of undesirable contaminants: plutoniu…

> None of the countries that have developed nuclear weapons have gotten their plutonium from nuclear waste

Just because someone hasn't done it before doesn't mean someone won't in the future.

You're also ignoring the larger threat to that plutonium; the issue that someone may not want to separate the contaminants. If they're making a dirty bomb, they don't care if it has contaminants or not.

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#155

Post by mahranch » Tue, Apr 14, 2015, 9:01 AM UTC

bcmit wrote: post #150

mindcruzer wrote: post #95

Earlier quoted context omitted.

No

Really? Water is just about the best radiation shield in existence. It would only affect the ~10 feet of ocean immediately around it.

It's not about the actual radiation, that's easy to deal with. It's about the containers cracking or leaking and having that stuff floating around in the ocean, contaminating our food and the environment. Even the strongest container we can make is still susceptible to the corrosive effects of the ocean.

If you're going to bury it in the ocean, your best bet would be to bury it near a subduction zone. But then you have the earth itself possibly being the cause of the container cracks and leaks.

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#156

Post by elcct » Tue, Apr 14, 2015, 9:06 AM UTC

Cerium wrote: post #137

InclinedPlane wrote: post #83

Earlier quoted context omitted.

To what end? To spend literally decades, perhaps centuries, with nuclear waste floating around the solar system? Why not just leave it in deep space to start with? Why bother sending it into space in the first place? Meanwhile, if you succeed in sending nuclear waste into the Sun what do you think happens to it? It doesn't go away, it just gets vaporized and then scattered into the solar wind.

Solar energy is simply a nuclear power system with a sensible waste disposal strategy.

But it also has not been approved by any authority. It is just like sending waste to some shady dude few blocks away "to take care of it"

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#157

Post by lmm » Tue, Apr 14, 2015, 9:07 AM UTC

sbov wrote: post #93

cpeterso wrote: post #48

Earlier quoted context omitted.

Or bury the nuclear waste in oceanic trenches. It is out of the way and future generations won't stumble upon it when humans forget where they buried all this stuff.

Do we know enough about our oceans to know that there would be no harm from this?

Define "know". Do we have it carved in tablets of stone from on high? No. Are we reasonably confident? Yes. There are already hotter things in the ocean (e.g. black smokers). What kind of effects are you worried about?

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#158

Post by lmm » Tue, Apr 14, 2015, 9:08 AM UTC

phkahler wrote: post #119

btilly wrote: post #109

Earlier quoted context omitted.

The biggest problem with the cannon idea is that things traveling at that speed in the atmosphere tend to burn up before getting anywhere. And you get to start in the hardest part of the atmosphere to move in.

Unless you put the cannon on the moon. It's much easier to rocket to the moon than the sun. Now the railgun or whatever launcher doesn't have an atmosphere to deal with. Use the cannon to take away earth orbital velocity from the waste. Throw in reusable rockets and... it's still really dumb. We have reactors that can make use of "spent" fuel - they're just not legal.

It takes more energy to send something to the moon than to send it escaping the earth.

Space elevator with a railgun at the top of it maybe makes sense.

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#159

Post by lmm » Tue, Apr 14, 2015, 9:09 AM UTC

wukerplank wrote: post #139

whoopdedo wrote: post #105

Earlier quoted context omitted.

And the space shuttles carried many more people than other space vehicles except for the current generation of Soyuz. You don't measure failure rate by number built divided by number crashed. You measure by how much it's used. The more often something is used the more likely it it that it will fail one of those times.

The problem with nuclear waste is that you need a 0% failure rate or you might detonate a dirty bomb in the atmosphere. It doesn't matter how often it worked if it fails once. Also it's a great target for sabotage for radicals.

> you might detonate a dirty bomb in the atmosphere

Which would put less radioactive material up there than coal power plants already do as a matter of course.

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#160

Post by lmm » Tue, Apr 14, 2015, 9:10 AM UTC

whoopdedo wrote: post #105

cryptoz wrote: post #63

Earlier quoted context omitted.

> When the Shuttle was first commissioned, my concern at the time was that America's most reliable rocket was the delta, which failed every thirty launches. You were right to be concerned. The shuttle had "a 40% vehicular failure rate and a flight failure rate of 1.5%", killing more people than any other space vehicle. [1] [1] http://www.forbes.com/sites/carolpinchefsky/2012/04/18/5-hor...

And the space shuttles carried many more people than other space vehicles except for the current generation of Soyuz. You don't measure failure rate by number built divided by number crashed. You measure by how much it's used. The more often something is used the more likely it it that it will fail one of those times.

> You don't measure failure rate by number built divided by number crashed.

Sure, you measure by number of launches divided by number crashed - or some similar measure that includes how much utility you get out of it. But the Shuttle does very poorly on any such measure.