Nuclear Waste Question

[RWB]

Currently watching a "Dangerous Cargo" thing on the History channel. One part was on Nuclear Waste and stuff, which got me thinking of a question...

If you got all the Nuclear Waste put together underground, then put a powerful Nuclear Bomb down with it, blow it to kingdom come, will Nuclear Waste only become worse? Or will it disentigrate like all other matter?

The reason I ask, is becuase 1) I don't know what nuclear watse looks like and thus don't have a clue what form it is in(liquid, gas, etc..) all though I feel nuclear waste is only the little Uranium rods they have that are no longer powerful enough to power nuclear plants, and therefore are "waste". 2) Nuclear Waste is rdioactive and so when you blow it up, the radiation is just let loose on a rampage instead of destroyed.

I figure "maybe" that after the stuff is nuked, the only radiation left is from teh bomb itself, but perhaps still less than what is in those little radioactive rods.

Also, I think weapons grade Uranium is U236 right? Is that the same as what they use to power Nuclear Plants? Or is it something different, U235 or something.

One last question, how do you get Depleted Uranium? I mean, if you manufacture it, why can't they "deplete" the uranium rods left over from Nuclear Plants?

[Missileman]

Also, I think weapons grade Uranium is U236 right? Is that the same as what they use to power Nuclear Plants? Or is it something different, U235 or something.

One last question, how do you get Depleted Uranium? I mean, if you manufacture it, why can't they "deplete" the uranium rods left over from Nuclear Plants?

Weapons grade Uranium is U238/239 (can be either depending on way it is enriched). U235 is natural uranium. Fuel rods from reactors are depleted uranium and are used to make Anti-Armor rounds for the M1A1 Abrams Tank, A-10 Warthog, Bradley FV, and many other bullets requiring a heavy dense metal. When fuel rods are completely drained they have very little radioactivity left so they can be processed to finish cleaning them so they can be used as a very hard dense metal.

I don't know a lot about nuclear physics but I do know about nuclear bombs/warheads :) I think nuking waste wouldn't work since it is a heavy matieral already it would only become more radioactive and become a contaminent in the ground since now it is atomized.

[Thrax]

1. If you nuked the uranium rods (One half of "Nuclear waste") you'd set it into a chain reaction. I know that you know that a nuclear device is merely the continuous splitting of radioactive atoms via an initial atomic split. The little atoms ricochet around and make the explosion as large as it needs to be.

Now, think about detonating a nuclear device in a pile of rods made out of largely the same nuclear material as you're using to <i>detonate</i> the nuclear device. The particle storm would just tear the atomic structure of the uranium rods apart and release what's left of its energy in an explosion.

2. Nuclear waste is comprised of two parts: The first is the depleted rods, and the second is the now-radioactive water in which the uranium matrices are submerged.

[Missileman]

I kinda wondered about that. I figured the rods would break down, but I don't believe they would add much to the explosion since they are in a depeleted state and would grab free electrons rather than release them.

Most of our warheads/bombs all use a 3 blast type chain reaction. A conventional explosive destroys a blocking barrier and physically forces 2 separate piles together. This is done with a ball shaped charge. This merging creates a critical mass fission explosion that is used to power an xray gun which then is used to set off the fusion reaction. The fusion reaction consumes the fission explosion. Course it all happens in nanoseconds. Most of our stuff is fusion based. Cleaner and less fallout/residuals.

Underground nukes are bad too since they are believed to excite fault lines as their shockwaves bounce around underground. Kinda upset the California people if you broke them off and drowned them to blow a big underground hole in Nevada or Utah :) :bigggrin:

[Nomad]

I can't wait for a bat with an 80 foot wingspan to come flying out of one of those caves if they ever unseal it.

[Thrax]

Attack at Yucca Mountain (C)Thrax 2004

[Nomad]

?

[profdlp]

A lot of noise is made about the nuclear waste question, but it is actually a fairly small problem, at least from a storage point of view. When I went to Naval Nuclear Power School in the late 70's we asked about that. (Some of our instructors were on shore duty while their boat was being re-cored.) We were told that all of the nuclear waste in the world would fit inside the Astrodome.

As far as disposal, there have been many creative ideas, like shooting it into space, etc. One thing to remember is that today's hazardous waste may be tomorrow's valuable resource. Coal miners used to vent off natural gas, since it was a safety hazard. The coal slurry was run into the nearest creek to get it out of the way. Today, both of those are used to generate power. All we need is for some enterprising soul to invent a way to do something useful with our nuclear leftovers. Who knows, it could be a key component in the Fusion process once that is developed.

Storing it in geologically stable caves is not a bad short-term (50 - 200 years) solution. The biggest problem is the hysteria raised by the word "nuclear", and the resulting NIMBY attitude.

[Lincoln]

the resulting NIMBY attitude.
I particularly like it when persons of that attitude have signs in their yard reading "No Garbage Dump in [town name]" accompanied by four cans of rubbish at the curb :rant:

[Thrax]

Convironmentalists. Environmentalists when it's convenient for them.

[Camman]

2. Nuclear waste is comprised of two parts: The first is the depleted rods, and the second is the now-radioactive water in which the uranium matrices are submerged.

How much water is actually in 'nuclear waste' out of curiosity? I know most nuclear power plants have two, or sometimes even 3 circuits to set the radioactive water apart from what is physically driving turbines. Obviously the water isn't "spent", when they refuel why don't they just drain it and then put it back in as to not create more radioactive wastewater? I don't know much about nuclear power plants just seeing if anybody knows.

And to whoever put the question mark about Yucca Mountain, it's the proposed site of a "national nuclear waste dump" site in Nevada which involves transporting nuclear waste off-site from power plants and into a central location inside a mountain. It's a bad idea because the waste needs to be transported cross country by truck or train and it's just a terrorist attack waiting to happen.

And honestly, I'm not one of these "environmentalist" types who is worried about shoving nuclear waste in a mountain. I'm definitly all for nuclear power, it's a cleaner operation than most coal plants by far. It's just been shown that it's safer to just store the waste on-site, it's worked so far, so why go through the trouble of shipping it across the country and creating a risk that doesn't have to be there.

[RADA]

1. If you nuked the uranium rods (One half of "Nuclear waste") you'd set it into a chain reaction. I know that you know that a nuclear device is merely the continuous splitting of radioactive atoms via an initial atomic split. The little atoms ricochet around and make the explosion as large as it needs to be.

Now, think about detonating a nuclear device in a pile of rods made out of largely the same nuclear material as you're using to <i>detonate</i> the nuclear device. The particle storm would just tear the atomic structure of the uranium rods apart and release what's left of its energy in an explosion.

2. Nuclear waste is comprised of two parts: The first is the depleted rods, and the second is the now-radioactive water in which the uranium matrices are submerged.


Thrax has it right, but you need to add any machinery tha was used to make the rods, any and all chemicals that have come in contact with U235 or U236. This also includes radiation suits, booties, gloves, the barrels that were used to store the pre-and post use chemicals.

An underground salt mine is an excellent place to store this type of stuff. Unfortuantely, as some have already mentioned, the eco-freaks would rather rant and rave than actually do something to alieviate the problem. Its OK to want to protect the environment, but scaring people so much that nothing gets done with the waste we already have is kind of counter productive.

Just my 2c, no flames intended. :thumbsup:

[profdlp]

Convironmentalists. Environmentalists when it's convenient for them.
Another great addition to my vocabulary. :)

Funny, but you never see any of the hardcore convironmentalists building outhouses. But they'll lobby for <strike> no-flow</strike>, uh, low-flow toilets.

I'm not opposed to environmentalists in general. In fact, I consider myself one. One of my personal hero's is Teddy Roosevelt, without whom we probably wouldn't have a Yosemite worth visiting. I have no use for the radicals who love every species which walks, crawls, flies, or swims except one - human beings. :rarr:

[Thrax]

I'm an environmentalist, too. In the sence that I think the world should be kept clean and pretty, and full of life.

But not at the expense of my hamburger.

[profdlp]

But not at the expense of my hamburger.
If it's true that all of those cow-farts are choking us with methane, eating them might be a very "green" thing to do.

No more pooners outta you, Elsie. :p

[mmonnin]

I always thought we should send it into space. Say goodbye to it forever that way. A single rocket every now and then would do the trick.

[profdlp]

I always thought we should send it into space...
And if there's another Challenger/Columbia? :eek2:

[mmonnin]

No one has to be onboard. Just a rocket.

[Thrax]

No, he's saying, "What if the rocket carrying metric tons of nuclear waste explodes, showering the atmosphere with radioactive particles?"

[bothered]

I don't think blowing it up would cause a bigger bang, as I understand it it has to get to critical mass (compression) to cause a detonation. Blowing it up would just,,,erm,,,,blow it up.
To leave this waste to (many, many) future generations is a little unfair but at present there is no alternative, we have to use nuclear power because we cannot go on using fossil fuels. So yeah, dig a very large hole in solid rock, encapsulate it and store it. It's bad enough in the ground, you wouldn't want it in the air or in the water.

[bothered]

I always thought we should send it into space. Say goodbye to it forever that way. A single rocket every now and then would do the trick.

This stuff is very very heavy, and like Thrax said, if anything happened to it we'd all get it back.

[Jengo]

Nuclear Water?

Well, they just put all the radioactive water in the ocean, really they do, it all spreads out over the ocean, thus lessening its radioactivity, it just all spreads so much that its almost normal water and would have no effect on humans...

well... at least thats what my teacher told me in 6th grade...

eh...

[RWB]

Wow, lots of replies, too little time to read, but I will later. But I know missile man said something about making the rods into weapons like depleted uranium slugs for conventional weapons if I am not mistaken? The rods are still DEADLY if you came into contact with them, they just are not strong enough to power a Nuke Plant effeciaently.

I need to scan a pretty cool picture I found in Steven Hawkings book "The Universe in a Nutshell". But later :D

[muddocktor]

First of all, Missileman got it a little bit backwards on the Uranium. After the ore is refined into Uranium, it's content is something like 99.5% U-238 and the rest is other isotopes of Uranium, including the easily fissionable U-235. Further refining separates the U-235 out of the Uranium and the U-235 is what is easily fissionable and is the primary in thermonuclear weapons and the main explosive power in a straight Uranium-fission bomb. The power plants that run in most of the world use mostly U-238 and the reason that the fuel rods need to be changed every so often is due to the rods themselves change character due to the constant bombardment of radioactivity and Plutonium-239, which is made by U-238 gaining a proton (or neutron, don't remember since I'm not into atomic stuff by trade ;) ), among other radioactive isotopes generated. U-238 is used in modern thermonuclear warheads as containment to initiate the fusion reaction though and it does contribute to the overall explosive power of a bomb, since a thermonuclear explosion is a compound explosion that utilizes a fission trigger to start the thermonuclear reaction. The water used in watercooled power reactors also becomes radioactive over time due to the buildup of deuterium and tritium (radioactive isotopes of water) in the water used to cool the pile and transfer the heat to the secondary loop.

The half life of some of the isotopes in the waste coming from these power plants is over 200,000 years and is extremely toxic to all life forms, not just animals and humans. And like Thrax and bothered have stated, a lot of this stuff is way too heavy and toxic to life to get rid of by launching into space for the reasons already stated, Marc. And you can't just set a nuclear weapon into a pile of radioactive waste and blow it up as even in a modern weapon, a lot of the material is actually wasted instead of contributing into the reaction. The result of blowing a thermonuclear weapon in a pile of radioctive waste would only spread radioactive contamination across wide areas of the earth. This nuclear waste stuff is easily the most scary stuff we in modern civilization have ever generated and the world needs to phase out present nuclear reactors due to this. How can we presume that we can keep this stuff safely stored for essentially forever? :rant: Bothered is right in that we can't continue using fossil fuels for power generation as it seems inevitable that the supply will eventually run out, but fission reactors aren't the answer either.

EDIT 1: Missileman is right about most of our weapons though; it's a 3 part fission-fusion-fission reaction. The primary, which I believe is a Plutonium-fission implosion reaction initiates a fusion reaction fueled by tritium. This in turn generates another fission reaction in the U-238 containmant material, which normally won't generate a fission reaction except at extremely high heat and pressure, which is generated by the fusion reaction. Like he said, this all takes place in nanoseconds.

EDIT 2: The first nuclear weapon designed was a U-235 gun type bomb, in which 2 parts of U-235 that were slammed together by conventional explosive shooting the subcritical masses into 1 supercritical mass fast enough to get a fission reaction (Little Boy). This was actually the first bomb designed but U-235 was extremely hard to refine out of the U-238. The implosion bomb, which uses Plutonium instead of Uranium, was designed due to the much larger quantity of Plutonium available at the time and uses the compression caused by the implosion waves of specially shaped conventional explosive to physically squeeze a subcritical spherical mass of Plutonium-239 into a supercritical mass. That was the first bomb actually exploded in Nevada (the Device) and was the second atomic weapon that was exploded over Japan (Fat Man).

[bothered]

Excellent info muddocktor. Thanks.
Right guys, who's for designing a fussion reactor? I'll start. First we need a big box, a kettle, some Tea bags and some pencils and paper.

[Missileman]

Yeah I got it all backwards like Mud said. Been a long time since I had to play with those numbers. Mud was right about the weapons too. Primary yield element is always Plutonium. Uranium is just the jumpstarter.

I think we are going to have to go to some type of hydrogen based plasma reactors to generate power. Burns clean, no waste, effecient. Just gonna take a lot of power to get it cranked up. Got to get it near I think 5K degrees to start to form Hydrogen into plasma. And magnetic bottles for containment draw a huge amount of power. Shutting down would take years too so you would have to get it right the first time.

Be a little closer to "Star Trek" using plasma for power and having ION based impulse engines and the like. Almost scary how somebody actually got so close to what is actually working out as reality 30 years before any of it existed. I know there was a lot of theories in existence but somebody assembled all the right ones :)

[EyesOnly]

Yeah plasma is the way to go. Nuclear is bad and i want to get rid of it but at the moment it's the best we have. :scratch: BTW how often does colombia happen? Not often really but i sure wouldn't want any sour rain that's for sure. :eek:

In the movie sum of all fears in the end usa and russia agree to destroy all nuclear weapons. I sure wish it could happen in reality as well. It would be nice to send them all into the sun but not so fun should a disaster happen to the ship carrying them. Hmm what should we do then.

[mmonnin]

Adding a proton to an atom will cause it to become another element. Adding Neutrons will make an isotope.

There has to be someway to contain the waste so that even if the rocket does blow up then the waste in the container will not be afftected.

How big are these rods anyway?

[muddocktor]

I'm sure Missileman can fill you in better than me on this but I'm sure you could develop a container that could contain the material in event of an explosion, but it would be so heavy that it would seriously limit the payload carried. Plus, a lot of the radioactive wastes are of heavy elements so you couldn't carry much volume of the wastes in that rocket either. The density of depleted Uranimium (U-238) is why they use it for armor piercing sabot rounds in tanks and stuff. Finally, the solid rocket fuel designs we presently use in ICBM's and the SRB's on the shuttle burn aluminum, which is extremely toxic in itself. You would probably end up polluting the atmosphere a lot more getting rid of this stuff in space than figuring out a way to entomb this crap here on the planet.

Like I said though, I'm sure Missileman can give you a more accurate answer on the rocket part.

[Missileman]

Mud's right again. Most solid rocket fuel components are classified, but as most anybody can find it is primarily aluminum based. The problem is fuel to weight as MD said. You must boost to 17.5K MPH to make orbit and 25K MPH to leave orbit. (Round numbers so be quiet). This makes the fuel ratio very high. More fuel = more weight = more fuel = etc... Becomes a circle. Since rocket fuel is explosive the more bang you would have to protect against which means more weight, which means more fuel. You see the dilemna. Basically becomes not cost effective REAL FAST.

To give you some idea what you are dealing with. The Cassini probe now in orbit around Saturn carries 72.3 pounds (32.8 kg, launch weight) of Plutonium - 238 and PU - 239. It is estimated that should this vehicle have failed during orbital insertion and vaporized on re-entry like the shutlle. It could have killed millions of people due to Plutonium contamination of the atmosphere. There was a huge effort to block it's launch and subsequent slingshot maneuver around Earth seven years ago. NASA always says it's RTG designs can withstand explosion re-entry intact. We have all seen their record on that stuff and I can guarantee no design is foolproof. So for safety's sake the use of radioactive power sources on space craft is kept to a minimum.

Nuclear rocket engines were deemed impractical due to the high weight requirements for shielding material to keep the crew from being cooked. Maybe someday we will find a material or stable isotope which will give a good shielding with little weight, but until then chemical rockets are the only "safe" way to go. Too bad they are only about 5% effecient at best.

"If we could only find some way to reduce gravity" hmmm.......

[RWB]

From what I saw in the documentary, the design of the cells holding the nuclear waste is pretty damned solid, I was truely amazed by it's integrity. They beat those things HARD!! Although they only test the tempurature too about 1400 degree's if I am not mistaken, which some eco-nut was claiming is not enough, I wouldn't know.

[Thrax]

They already have a fusion reactor!

The Tokamak Nuclear Fusion Reactor. It's a toroidal magnetic plasma confinement device. It produces MFE, or magnetic fusion energy. It uses a phyiscally-stable ring of electromagnetic containment to steer plasma flows after essentially detonating a deuterium/tritium pellet with a laser matrix.

There are other kinds of fusion too; inertial fusion energy, which is where a D-T pellet is ignited by a heavy ion or laser beam, and then compressed at high velocities.

But basically, most of the fusion development of the latter half of the 20th century has come from Tokamak, as its the most stable fusion concept we've got. It has been successfully running for hours at a time, producing several hundred thousand megawatts of power. It's current troubles include:

1. Getting the neutronic reaction under control.
2. Producing more energy than it takes to run.
3. Further refinement of plasma containment practices.


Future goals include:

1. Cold-fusion, or a reaction which produces a heatless aneutronic result.
2. Self-sustaining controlled fusion reactions. Reactions which keep themselves going, but can be told to stop.

[deicist]

A space elevator would solve all our 'getting stuff into orbit' problems, stuff in this case including nuclear waste. And, according to this (http://www.xposed.com/headline_news/72_ds_619094.aspx) we could have one up and running by 2015. That seems a litle optimistic to me, but the concept is sound.

[csimon]

not just into orbit but headed directly toward the sun ...then it would no longer exist!

[EyesOnly]

As long as it gets into space, sending it into the sun shouldn't be to much of a problem if i'm right. Correct me if i'm wrong but the hard part is overcomming gravity. If a space elevator was used to get the stuff in orbit then only a smaller rocket would be needed to carry it into the sun.

When we're on the subject of fusion. I guess most of us have seen the movie chain reaction. My question is: If a fusion reactor was to go south, what would happen? Would there be a massive chockwave or would it at most destroy the building it's housed in? It it even possible to foresee what would happen?

[profdlp]

...If a fusion reactor was to go south, what would happen?...
The idea behind fusion is that you take two relatively stable elements and combine (fuse) them into another stable element. If something goes wrong they stop combining and the whole operation merely shuts down.

With fission you are taking an unstable element, stabilizing it via the reactor design, then allowing it to become slightly unstable again to produce heat.

A crude analogy would be the difference between a train that loses it brakes on a downhill slope, (look out below!) and a train that loses its brakes while traveling on level ground. The second train would just slow down and eventually stop.

[Armo]

Adding a proton to an atom will cause it to become another element. Adding Neutrons will make an isotope.



couldnt u theoreticly make the nuclear waste into another element?

[test_tube_tony]

hehehe. dont get me started hehehehe..... :D
this thread is right up my alley. sometimes i love being a nerd.

[bothered]

Something worse than plutonium? probably.

[bothered]

I'd like to put my name down for the next new element. botherdium. And it probably would.