If it is the bomb that Duke has found, the question now is what, if anything, should be done with it?"
It should be retrieved. If this were a modern fission-fusion-fission bomb, it wouldn't be a concern. The Air Force says it doesn't have the fission trigger installed, so with a modern device that means you don't have a bomb. You need a fission bomb to ignite the lithium deuteride in the fusion stage, and you need the neutrons from the fusion stage to fission the U-238 jacket. So, again, no primary, no bomb. Leave it there, rivers already feed natural uranium into the oceans at a rate of 3.2x10^4 tons every year.
But this isn't a modern bomb, it was a transitional device between the earliest, liquid-dueterium monsters and modern three-stage designs. They weren't yet sure how to achieve efficient compression of the fusion stage, so they wrapped the bomb in highly-enriched uranium to be sure the fusion stage would light off. The bomb had a design yield of 1.7 megatons, and something like 1.3 megatons of that would be due to the fission of the U-235 jacket.
That means that this bomb contains a lot of almost-weapons-grade uranium. Again, 1.3 megatons of yield from the fission of uranium. The largest pure-fission bomb we ever detonated was the 500-kiloton Mark 18 prototype, and that used about 60 kilograms of HEU. Assuming linear scaling, that means we're looking at upwards of 156 kilograms of HEU in this bomb. Critical mass of uranium's about 16 kilograms. Double that to overengineer a bomb, and that means whoever gets their mitts on this thing could build 4 or 5 crude Hiroshima-type bombs, each with a yield of several kilotons.
That's bad. They need to retrive this thing, even if there's a risk they blow it up in situ. I'd rather have some of this stuff scattered in an unusable form offshore than have Mohammed and his band of Merry Pranksters get their hands on 4 or 5 cities' worth of U-235.
Its non-functioning, nukes have a shelf life of ~5 years before the plutonium turns into another isotope.
Steaming pile of bullshit. I swear, if the subject has the word "nuclear" in it, Slashdot's about as reliable as the Weekly World News.
The isotope of plutonium used in nuclear weapons is Pu-239. Pu-239 has a half-life of 24,100 years. After 5 years, almost all of the Pu-239 in a nuclear weapon will still be Pu-239.
In addition the Mark 15 Mod 0's an odd bomb.
Modern thermonuclear weapons are three-stage devices. There's a small fission trigger, whose yield is boosted by tritium injection. The radiation from the trigger ignites fusion in a second stage of lithium deuteride. Then the neutrons coming off of the fusion stage can be used to fission the bomb's tamper, made of uranium-238. U-238 won't sustain a chain reaction, but it'll fission merrily if you bombard it with fast neutrons. So, basically the boosted primary accounts for a minority of the weapon's yield, and the second stage, the fusion segment, accounts for the majority. But you can design things so that the majority of the yield comes from fission of the U-238 tamper.
The Mark 15's kind of an inversion of this. It was an early fusion bomb, back when they were still using liquid deuterium in some designs. In the Mark 15 Mod 0, the third stage is the bomb's casing, which is made of highly-enriched uranium, almost pure U-235.
Yes, the bomb's casing is almost-weapons-grade uranium. By making the case out of HEU, they didn't need to worry so much about efficient compression of the fusion stage, because the fissioning of that huge amount of HEU would send the whole thing thermonyclear. Inefficient, sure, but they hadn't quite figured everything out yet.
That's why this bomb's a concern. According to the Air Force, the primary, the 'pit,' wasn't placed in the bomb, so the primary can't detonate. Even if they're bullshitting, the twin traumas of impact and age have probably so screwed up the internals of the bomb that the only detonation possible would be low-order, a fizzle, biggest problem would be the environmental effects of scattering that much radioactive material into the river.
So that's not the concern. The concern is that whoever recovers it now has his hands on well over a ton of weapons-grade uranium, easily enough to make not one, but several crude Hiroshima-type nuclear bombs. I mean, this was a bomb that had a total yield of 1.7 megatons, and 1.3 megatons of that came from fission. That's a lot of U-235.
Obviously not - since you didn't know the stuff is mostly silicon and is safe enough to use in building materials.
Okay, you're clearly a fucking idiot. Coal ash isn't just silicon, it's oxides of aluminum, calcium, magnesium, sodium, arsenic, sulfur, and mercury. Yes, the bulk of it is pretty much inert, but the contaminants are present in sufficiently large amounts to be an environmental hazard.
It's safe to use in building materials because when you encapsulate it in concrete you're sealing the toxins in it off from the surrounding environment. I never claimed otherwise.
There are plenty of real toxic materials that should be treated with respect instead of inventing some stuff about fly ash being radioactive waste.
You also are illiterate. I never claimed that fly ash was radioactive waste. What I mentioned was the fact that uranium and thorium isotopes are present in significant quantities in coal, and when that coal is burned those elements are oxidized and emitted into the atmosphere just like the carbon is.
Using these data, the releases of radioactive materials per typical plant can be calculated for any year. For the year 1982, assuming coal contains uranium and thorium concentrations of 1.3 ppm and 3.2 ppm, respectively, each typical plant released 5.2 tons of uranium (containing 74 pounds of uranium-235) and 12.8 tons of thorium that year. Total U.S. releases in 1982 (from 154 typical plants) amounted to 801 tons of uranium (containing 11,371 pounds of uranium-235) and 1971 tons of thorium. These figures account for only 74% of releases from combustion of coal from all sources. Releases in 1982 from worldwide combustion of 2800 million tons of coal totaled 3640 tons of uranium (containing 51,700 pounds of uranium-235) and 8960 tons of thorium.
Maybe try hiring an adult to read my posts to you next time.
Simply, you understand wrong. Here's some stuff from a 1983 article on the issue.
Uranium in 1983 cost $40 a pound. Uranium reserves extractable at that price would indeed only last for 50 years or so if you burn it in light-water reactors. At $40 a pound, in 1983, those fuel costs added about 0.2 cents per kilowatt hour to the cost of electricity.
If, on the other hand, you use breeder reactors, which use the fuel far more efficiently, you can pay $1000 per pound for your uranium, and those fuel costs would only add 0.03 cents per kilowatt hour to the cost of electricity. Clearly, that makes economical the extraction of ores that wouldn't be economical if you were only using LWRs and PWRs.
You could extract uranium from seawater for far less than $1000 per pound, probably $200 to $400 a pound, and there's enough uranium current dissolved in seawater (4.6x10^9 tons of it) to supply the worlds electrical generation needs for millions of years. And, actually, that's renewable; rivers continually add more uranium to the seas.
Extract 16,000 tons per year from the oceans, and you can supply 25 times the world's 1983 electrical usage, and twice the world's 1983 total energy consumption.
There's way, way, way, way, way, way, way, way, way more than 50 years' worth of uranium around. And we haven't even mentioned using thorium, which is about 4 times as abundant in the Earth's crust as uranium, or just breeding plutonium from U-238, which is a lot more abundant than U-235.
It may be made from concrete that contains that evil, nasty fly ash!
Thus locking any toxins in it up in a relatively inaccessible form. Nothing wrong there.
Of course, the vast and overwhelming majority of flyash doesn't get turned into concrete building materials, and mostly sits in big piles by the facilities that generate it, exposed to the elements and leaching into the soil like all get-out. I'm from northeastern Pennsylvania, so I'm well aware of the properties and disposal of flyash; some of my engineering professors have done a lot of research on just what to do with the stuff, as there's considerable economic pressure in the region to turn the piles of toxic garbage laying around the place into some sort of economic resource. And yet, there are still piles of toxic garbage laying all around the place; I've driven up and over some of them in a Jeep.
people are not considered nuclear waste
People aren't considered nuclear waste because it would be inconvenient to do so.
If people *were* considered nuclear waste, you wouldn't be allowed to cremate them, dispersing that material into the atmosphere. You wouldn't be allowed to bury them in simple wooden coffins.
Low-level nuclear waste that's about or even less radioactive than the human body has a body of regulations governing its disposal that's orders of magnitude larger and more complicated than those governing the disposal of human bodies.
So go tell the people who crafted those laws and regulations about "concentration."
and the energy balance is heavily dependent on finding uranium with a high concentration of the good isotope, else the enrichment costs eat up money and energy.
Nonsense. Breed the stuff, don't worry about digging it out of the ground.
Nobody wants to build them anymore because of the ridiculous liability concerns, which is hardly fair. Coal plants kill way more people than nuclear plants do, by crudding up the air. They cause respiratory problems, they shorten lifespans, and the radiation they spew into the air causes cancers. But people have this notion that if you distribute a problem widely enough, it suddenly becomes not a problem anymore, and so you can't sue coal plants when they thorium they emit as a waste product gives you cancer.
Compressed hydrogen needs to be a ~1000 psi to get a sufficiently high energy density...and that will make for one interesting car crash.
Ah, come on.
Gasoline has an energy content of 45 megajoules per kilogram, or 56 MJ per liter. Energy density of hydrogen is about 11 kilojoules per liter.
My car gets about 325 miles on a 16-gallon tank, so that's 60 liters of gas, or about 3400 megajoules. To get that same amount of energy from hydrogen, I'd need 309100 liters of the stuff, at STP. To fit that into a 16-gallon tank, I'd need to pressurize it to about 5000psi, or about 340 atmospheres.
Not particularly difficult to build a tank that can hold that. Not even particularly difficult to build a tank that can hold that and still have a huge safety margin. HY80 steel, ferinstance, has a yield strength of (surprise!) 80,000psi on a one-inch thickness. Even aluminum might do the job; 5083 H-116 plate has a yield strength of 34,000 psi. Sure, you're carrying around a tank of highly-compressed hydrogen, but making a tank that's strong enough not to rupture in approachingly-normal circumstances, and connecting it to the car with a strong enough leakage that it won't break itself free and go flying into the next county if it *does* happen to rupture is hardly a game-breaker. Hell, cars today carry around tanks of a highly-flammable liquid in a tank of thin sheet steel, and those rarely rupture, and people aren't concerned about the safety of it.
No, the key issue with hydrogen is that there's no good way to produce it. Until you go all-nuclear, electrolysis is ridiculously expensive, and steam-reformation of hydrocarbons doesn't really help you.
Leaks? Get the production cost low enough and nobody'll care about leaks, anymore than they care about the trickle of water leaking from a car's exhaust pipe.
Burning coal produces waste that remains toxic forever. Half-lives come and go, but arsenic is forever.
Nuclear power is environmentally friendly because the amounts of waste you're talking about are incredibly low for all the energy you're getting out. You're looking at around 23 tons of high-level waste per megawatt of plant per year, at a 91% duty cycle. And this is dense stuff, by the way, so volumetrically it's a very small amount. It's also in a relatively convenient-to-handle form; it's not discharged into the air or the water.
Compare that to a coal plant, where you're generating 1.5 million tons of ash per megawatt of plant per year, which is vastly more polluting, and that's not even considering the CO2. For every single kilowatt-hour of energy you get fro burning coal, you produce a kilogram of CO2. So if you run your megawatt coal plant on a 70% duty cycle, generating 8800 megawatt-hours,you dump 4400 tons of CO2 into the atmosphere.
And that fly-ash you're making is toxic forever. It's caustic. It's filled with heavy metals. Both in terms of mass and volume you've got orders of magnitude more of it to deal with than you would if you went nuclear. And if you're concerned about radiation, well, burning coal releases uranium and thorium isotopes right into the atmosphere; coal has up to 10ppm of uranium in it. Since 1937, burning coal in the United States alone has dumped 145,000 tons of uranium and 357,000 tons of thorium into the air; that radiation's just as real as the stuff in nuclear waste, and the cancers it causes and the people it kills are just as real.
Let's pick a random small country, like the UK. From what I can find, they have a generation capacity of 361 terawatt-hours per year. 8765 hours in a year, 91% duty cycle, so 8000 hours. To produce 361 terawatt-hours in 8000 hours, you need 4500 megawatts of plant. So if the UK went all-nuclear, they'd generate just a bit over 100 tons of high-level waste per year.
They could take that, put it in thin-walled steel drums, and dump it right to the bottom of the North Sea, and they'd be doing vastly less environmental damage than they're doing now, by getting 74% of the electricy from burning fossil fuels and dumping 614 billion pounds of CO2 into the air every year.
That 145,000 tons of uranium the US has dumped into the air just by burning coal, since 1937? Well, that's 10440 tons of U235, which if you fission it (okay, with perfect effiency. This is just to illustrate a point) produces 17.6 kilotons of energy per kilogram. If you fission 10440 tons of it, you end up with 193 petawatt-hours. That right there's the electrical needs of the entire UK for 500 years, at present rates of consumption.
By all those metrics is nuclear power environmentally friendly. It's utterly ridiculous that we're not embracing the technology and making our electricity the right way.
, I could easily fire the weapon with no intent to kill.
Yes. That's what you're supposed to do. You shoot to stop a threat, not to kill.
Aim for shoulders, arms, or legs
Dear Lord, no, that's an absolutely horrible idea, and even if it works you just increased your likelihood of going to jail by quite a lot.
A handgun is not a weapon generally capable of precision fire in stressful situations. When you train to use a gun, you learn to aim at the target's center of mass, because this maximizes your chances of hitting at all. That 'aim for his leg' bullshit is exactly the sort of 'Hollywood portrayal that doesn't happen in real life' that you're griping about.
If you shoot that guy in the leg, then when you end up on the stand, the prosecutor is going to ask you why you shot him in the leg. It will be pointed out that if you honestly felt your life was in danger, you wouldn't have shot him in the leg, and that the fact that you did is evidence you weren't acting in legitimate self defense.
Bad, bad, horrible, awful, Hollywood-influenced idea. If you happen to own a gun, please go out and take a real self-defense course, instead of repeating what you see in movies.
Only a fraction of total force strength is combat capable
And only a fraction of total force strength in Iraq is combat-capable. It's not like those 125,000 guys all are on the line with M-16s and M1A1s, and the other 1.2 million all have typewriters.
Maintaining the forces in Iraq plus their replacements in rotation has tapped out the US military.
It's putting a strain on transport capability, not manpower.
That's why enlistments are being involuntarily extended and chronically ill 55-year-old reservists are being called up.
Enlistments are always extended in times of war. Stop-loss orders are nothing new, and happened during the Gulf War. American military doctrine places reserve forces alongside regular units on the TOEs. That old reservist who got called up ha d a somewhat specialized skill that was in short supply: he was a psychiatrist.
Look, the IRR is not the bottom of the barrel, to be called up only as a last resort only when everyone else is spoken for. Our military doctrine regards it as an integral part of the force composition, to be used when it will be useful, and the fact that we re-activate people who are fulfilling their reserve requirements doesn't indicate that we've hit bottom.
He was calling up the IRR because it's been American military doctrine for decades that major wars will be fought by a cross-section of the military that includes the reserves; this dates way the hell back to the rebuilding of the armed forces and the reshaping of doctrine that took place in the aftermath of Vietnam.
You think if we needed those forces stationed in Blenheim somewhere else we couldn't, like, move them? Or would that leave the Fulda Gap wide open to hordes of Soviet T-72s?
The signal spectra. In other words, the same thing that makes the signature of an explosion different than the signature of an earthquake. Hell, the Fast Fourier Transform was originally used for the very purpose of distinguishing between earthquakes and nuclear tests.
It's not humbling. It's just an indication at how grotesquely incompetent the mainstream media has become at reporting anything more significant than who got voted off the island.
Besides, "mushroom-shaped" clouds form from all large explosions, not just nuclear ones. Set off a big bomb, and you suddenly generate a large amount of superheated gas in a pocket near the ground. This rises so rapidly that it generates vortices around its perimeter, and the rolling of these vortices draws up a column of smoke and explosion debris, forming the stem. Then when the rising gas reaches a higher altitude where it's just about as dense as the surrounding air, it spreads out, forming the cap.
A mushroom cloud could be from a nuke. It could also be from the explosion of a liquefied natural gas storage facility, or a MOAB, or cargo train filled with ANFO. It's not a tell-tale of anything other than a big explosion.
It's more than just the US military that would know about it.
So would seismologists. Unless the US intelligence community recently clamped down on seismic research labs all across the free world, I'm pretty sure there'd be seismologists in various countries around the globe saying that they've recorded the seismic signature of a nuclear test.
Nowhere near "all of our troops" are in Iraq. We've got about 125,000 troops in Iraq. That includes Army, Marines, Air Force, Navy, and significant numbers of National Guard troops.
That's about two Canadian Armed Forces' worth of troops, but only a fraction of our total force strength.
And here's a big, big question for everyone who's going to bleat "Well why'd we send those troops to Iraq instead of North Korea?":
The city of Seoul is home to eleven million people. The city of Seoul is also within artillery range of North Korea. Artillery is cheap and ubiquitous, and as North Korea's army is arrayed along Soviet lines, they have scads of it. Until it fires, it's damned hard to spot camoflaged artillery from the air, and even if you could spot all of it, the sheer number of artillery pieces they have is quite staggering.
If you have a plan for military intervention in North Korea that doesn't lead to the virtual annihilation of Seoul within hours of the start of the war, please, we're all ears.
No, I'm not. That was just an example. Radio allows us to look at a helluva lot more places than just Proxima Centauri.
We're not looking for ET here: we're looking for any sign of life
And SETI's looking for ET, not just any sign of life.
Don't you see that you've created a false dichotomy? For all the money spent on SETI, you couldn't afford even a single Mars probe. And SETI isn't stopping us from sending Mars probes. So why present this issue as you have, as a choice between either radio telescopy or physical search, but not both?
I'm looking at them. I'm looking at hundreds of millions of dollars spent to "physically search" a tiny portion of the surface area of a planet that's about 50 million miles away.
The nearest star to earth, Proxima Centauri, is 24,698,699,219,682 miles away. Let's plug some numbers into the rocket equation, shall we? Vfinal = Vexhaust * ln(Minitial/Mfinal)) + V(initial).
Let's imagine some hypothetical chemical system that's way better than what we're using today, call it chlorine pentafluoride and hydrazine, something real messy, and end up with an exhaust velocity of around 4500 meters per second. Escape velocity from 1AU orbital radius is about 50 kilometers per second. If you want to "physically search," you need to slow down at the other end, too, so that's 100kps delta-vee.
100000 = 4500 * ln(x), solve for x, x comes out to about 4.5 billion. So to get a payload consisting of the Spirit rover's 175 kilograms to another star, you'd need to burn 787 billion kilograms of propellant.
Now, granted, for a more precise formulation you'd go to Newton instead of just algebra. But on the other hand, I'm also assuming a massless ship. And I'm not even considering how *long* the voyage would take, I'm just talking about getting up to escape velocity at one end and slowing down to avoid cratering at the other end. At 50 kilometers per second, to travel 4.4 light years would take 27,000 years. If you want to carry more useful payload, or you want to cover that distance faster, your fuel load goes up, literally exponentially.
I repeat: Sticking up a radio antenna lets you search a helluva lot larger area in a helluva lot shorter time, for a helluva lot less money, than "physically searching" does. The physical search you advocate is in no way, shape, or form technically or economically feasible at this point in time.
We're basically sitting here waiting for a message, when we should be physically searching.
This is silly.
Sticking up a radio antenna lets you search a helluva lot larger area in a helluva lot shorter time, for a helluva lot less money, than "physically searching" does. The physical search you advocate is in no way, shape, or form technically or economically feasible at this point in time.
Here's a though, RTFL. If you'd read the link you provide, and actually looked at the data as it is presented, you'd see that they break the challenges down by type of initiator, institution, etc.
So for "Institution," they show how many institutions challeneged were schools, school libraries, universities, theaters, public libraries, and so forth. They don't name specific institutions.
Which isn't exactly, or even close to exactly, what I was talking about.
Slashdot Mirror
If it is the bomb that Duke has found, the question now is what, if anything, should be done with it?"
It should be retrieved. If this were a modern fission-fusion-fission bomb, it wouldn't be a concern. The Air Force says it doesn't have the fission trigger installed, so with a modern device that means you don't have a bomb. You need a fission bomb to ignite the lithium deuteride in the fusion stage, and you need the neutrons from the fusion stage to fission the U-238 jacket. So, again, no primary, no bomb. Leave it there, rivers already feed natural uranium into the oceans at a rate of 3.2x10^4 tons every year.
But this isn't a modern bomb, it was a transitional device between the earliest, liquid-dueterium monsters and modern three-stage designs. They weren't yet sure how to achieve efficient compression of the fusion stage, so they wrapped the bomb in highly-enriched uranium to be sure the fusion stage would light off. The bomb had a design yield of 1.7 megatons, and something like 1.3 megatons of that would be due to the fission of the U-235 jacket.
That means that this bomb contains a lot of almost-weapons-grade uranium. Again, 1.3 megatons of yield from the fission of uranium. The largest pure-fission bomb we ever detonated was the 500-kiloton Mark 18 prototype, and that used about 60 kilograms of HEU. Assuming linear scaling, that means we're looking at upwards of 156 kilograms of HEU in this bomb. Critical mass of uranium's about 16 kilograms. Double that to overengineer a bomb, and that means whoever gets their mitts on this thing could build 4 or 5 crude Hiroshima-type bombs, each with a yield of several kilotons.
That's bad. They need to retrive this thing, even if there's a risk they blow it up in situ. I'd rather have some of this stuff scattered in an unusable form offshore than have Mohammed and his band of Merry Pranksters get their hands on 4 or 5 cities' worth of U-235.
Its non-functioning, nukes have a shelf life of ~5 years before the plutonium turns into another isotope.
Steaming pile of bullshit. I swear, if the subject has the word "nuclear" in it, Slashdot's about as reliable as the Weekly World News.
The isotope of plutonium used in nuclear weapons is Pu-239. Pu-239 has a half-life of 24,100 years. After 5 years, almost all of the Pu-239 in a nuclear weapon will still be Pu-239.
In addition the Mark 15 Mod 0's an odd bomb.
Modern thermonuclear weapons are three-stage devices. There's a small fission trigger, whose yield is boosted by tritium injection. The radiation from the trigger ignites fusion in a second stage of lithium deuteride. Then the neutrons coming off of the fusion stage can be used to fission the bomb's tamper, made of uranium-238. U-238 won't sustain a chain reaction, but it'll fission merrily if you bombard it with fast neutrons. So, basically the boosted primary accounts for a minority of the weapon's yield, and the second stage, the fusion segment, accounts for the majority. But you can design things so that the majority of the yield comes from fission of the U-238 tamper.
The Mark 15's kind of an inversion of this. It was an early fusion bomb, back when they were still using liquid deuterium in some designs. In the Mark 15 Mod 0, the third stage is the bomb's casing, which is made of highly-enriched uranium, almost pure U-235.
Yes, the bomb's casing is almost-weapons-grade uranium. By making the case out of HEU, they didn't need to worry so much about efficient compression of the fusion stage, because the fissioning of that huge amount of HEU would send the whole thing thermonyclear. Inefficient, sure, but they hadn't quite figured everything out yet.
That's why this bomb's a concern. According to the Air Force, the primary, the 'pit,' wasn't placed in the bomb, so the primary can't detonate. Even if they're bullshitting, the twin traumas of impact and age have probably so screwed up the internals of the bomb that the only detonation possible would be low-order, a fizzle, biggest problem would be the environmental effects of scattering that much radioactive material into the river.
So that's not the concern. The concern is that whoever recovers it now has his hands on well over a ton of weapons-grade uranium, easily enough to make not one, but several crude Hiroshima-type nuclear bombs. I mean, this was a bomb that had a total yield of 1.7 megatons, and 1.3 megatons of that came from fission. That's a lot of U-235.
This was the device tested as Castle Nectar.
Now where did that come from?
Jesus fucking Christ. From the plants that turned into coal, of course.
Now where did that come from?
Coal generally contains concentrations of uranium of from 1 to 10 parts per million, and from 2 to 4 times as much thorium.
Here. Here Here Here.Here.Here.
Those numbers are just a little high for something that is laid down in sediemnts.
Or maybe you just don't know what the hell you're talking about.
Okay, you're clearly a fucking idiot. Coal ash isn't just silicon, it's oxides of aluminum, calcium, magnesium, sodium, arsenic, sulfur, and mercury. Yes, the bulk of it is pretty much inert, but the contaminants are present in sufficiently large amounts to be an environmental hazard.
It's safe to use in building materials because when you encapsulate it in concrete you're sealing the toxins in it off from the surrounding environment. I never claimed otherwise.
There are plenty of real toxic materials that should be treated with respect instead of inventing some stuff about fly ash being radioactive waste.
You also are illiterate. I never claimed that fly ash was radioactive waste. What I mentioned was the fact that uranium and thorium isotopes are present in significant quantities in coal, and when that coal is burned those elements are oxidized and emitted into the atmosphere just like the carbon is.
Here:
Maybe try hiring an adult to read my posts to you next time.
Simply, you understand wrong. Here's some stuff from a 1983 article on the issue.
Uranium in 1983 cost $40 a pound. Uranium reserves extractable at that price would indeed only last for 50 years or so if you burn it in light-water reactors. At $40 a pound, in 1983, those fuel costs added about 0.2 cents per kilowatt hour to the cost of electricity.
If, on the other hand, you use breeder reactors, which use the fuel far more efficiently, you can pay $1000 per pound for your uranium, and those fuel costs would only add 0.03 cents per kilowatt hour to the cost of electricity. Clearly, that makes economical the extraction of ores that wouldn't be economical if you were only using LWRs and PWRs.
You could extract uranium from seawater for far less than $1000 per pound, probably $200 to $400 a pound, and there's enough uranium current dissolved in seawater (4.6x10^9 tons of it) to supply the worlds electrical generation needs for millions of years. And, actually, that's renewable; rivers continually add more uranium to the seas.
Extract 16,000 tons per year from the oceans, and you can supply 25 times the world's 1983 electrical usage, and twice the world's 1983 total energy consumption.
There's way, way, way, way, way, way, way, way, way more than 50 years' worth of uranium around. And we haven't even mentioned using thorium, which is about 4 times as abundant in the Earth's crust as uranium, or just breeding plutonium from U-238, which is a lot more abundant than U-235.
It may be made from concrete that contains that evil, nasty fly ash!
Thus locking any toxins in it up in a relatively inaccessible form. Nothing wrong there.
Of course, the vast and overwhelming majority of flyash doesn't get turned into concrete building materials, and mostly sits in big piles by the facilities that generate it, exposed to the elements and leaching into the soil like all get-out. I'm from northeastern Pennsylvania, so I'm well aware of the properties and disposal of flyash; some of my engineering professors have done a lot of research on just what to do with the stuff, as there's considerable economic pressure in the region to turn the piles of toxic garbage laying around the place into some sort of economic resource. And yet, there are still piles of toxic garbage laying all around the place; I've driven up and over some of them in a Jeep.
people are not considered nuclear waste
People aren't considered nuclear waste because it would be inconvenient to do so.
If people *were* considered nuclear waste, you wouldn't be allowed to cremate them, dispersing that material into the atmosphere. You wouldn't be allowed to bury them in simple wooden coffins.
Low-level nuclear waste that's about or even less radioactive than the human body has a body of regulations governing its disposal that's orders of magnitude larger and more complicated than those governing the disposal of human bodies.
So go tell the people who crafted those laws and regulations about "concentration."
Actually, I just did a BOTE and realized I could have made that entire post much shorter. Here's the shorter version.
Chemical:
One pound of coal = 926 watt-hours = 3.36 megajoules.
Nuclear
One pound of coal = 5-millionths of a pound of uranium (median value) = 0.000000036 pounds U235 = 1.20 megajoules.
In other words, you'd get almost one-third the energy you get from burning coal from fissioning the uranium that's in the coal you burn.
and the energy balance is heavily dependent on finding uranium with a high concentration of the good isotope, else the enrichment costs eat up money and energy.
Nonsense. Breed the stuff, don't worry about digging it out of the ground.
Nobody wants to build them anymore because of the ridiculous liability concerns, which is hardly fair. Coal plants kill way more people than nuclear plants do, by crudding up the air. They cause respiratory problems, they shorten lifespans, and the radiation they spew into the air causes cancers. But people have this notion that if you distribute a problem widely enough, it suddenly becomes not a problem anymore, and so you can't sue coal plants when they thorium they emit as a waste product gives you cancer.
That's just silly, no matter how you look at it.
Compressed hydrogen needs to be a ~1000 psi to get a sufficiently high energy density...and that will make for one interesting car crash.
Ah, come on.
Gasoline has an energy content of 45 megajoules per kilogram, or 56 MJ per liter. Energy density of hydrogen is about 11 kilojoules per liter.
My car gets about 325 miles on a 16-gallon tank, so that's 60 liters of gas, or about 3400 megajoules. To get that same amount of energy from hydrogen, I'd need 309100 liters of the stuff, at STP. To fit that into a 16-gallon tank, I'd need to pressurize it to about 5000psi, or about 340 atmospheres.
Not particularly difficult to build a tank that can hold that. Not even particularly difficult to build a tank that can hold that and still have a huge safety margin. HY80 steel, ferinstance, has a yield strength of (surprise!) 80,000psi on a one-inch thickness. Even aluminum might do the job; 5083 H-116 plate has a yield strength of 34,000 psi. Sure, you're carrying around a tank of highly-compressed hydrogen, but making a tank that's strong enough not to rupture in approachingly-normal circumstances, and connecting it to the car with a strong enough leakage that it won't break itself free and go flying into the next county if it *does* happen to rupture is hardly a game-breaker. Hell, cars today carry around tanks of a highly-flammable liquid in a tank of thin sheet steel, and those rarely rupture, and people aren't concerned about the safety of it.
No, the key issue with hydrogen is that there's no good way to produce it. Until you go all-nuclear, electrolysis is ridiculously expensive, and steam-reformation of hydrocarbons doesn't really help you.
Leaks? Get the production cost low enough and nobody'll care about leaks, anymore than they care about the trickle of water leaking from a car's exhaust pipe.
Burning coal produces waste that remains toxic forever. Half-lives come and go, but arsenic is forever.
Nuclear power is environmentally friendly because the amounts of waste you're talking about are incredibly low for all the energy you're getting out. You're looking at around 23 tons of high-level waste per megawatt of plant per year, at a 91% duty cycle. And this is dense stuff, by the way, so volumetrically it's a very small amount. It's also in a relatively convenient-to-handle form; it's not discharged into the air or the water.
Compare that to a coal plant, where you're generating 1.5 million tons of ash per megawatt of plant per year, which is vastly more polluting, and that's not even considering the CO2. For every single kilowatt-hour of energy you get fro burning coal, you produce a kilogram of CO2. So if you run your megawatt coal plant on a 70% duty cycle, generating 8800 megawatt-hours,you dump 4400 tons of CO2 into the atmosphere.
And that fly-ash you're making is toxic forever. It's caustic. It's filled with heavy metals. Both in terms of mass and volume you've got orders of magnitude more of it to deal with than you would if you went nuclear. And if you're concerned about radiation, well, burning coal releases uranium and thorium isotopes right into the atmosphere; coal has up to 10ppm of uranium in it. Since 1937, burning coal in the United States alone has dumped 145,000 tons of uranium and 357,000 tons of thorium into the air; that radiation's just as real as the stuff in nuclear waste, and the cancers it causes and the people it kills are just as real.
Let's pick a random small country, like the UK. From what I can find, they have a generation capacity of 361 terawatt-hours per year. 8765 hours in a year, 91% duty cycle, so 8000 hours. To produce 361 terawatt-hours in 8000 hours, you need 4500 megawatts of plant. So if the UK went all-nuclear, they'd generate just a bit over 100 tons of high-level waste per year.
They could take that, put it in thin-walled steel drums, and dump it right to the bottom of the North Sea, and they'd be doing vastly less environmental damage than they're doing now, by getting 74% of the electricy from burning fossil fuels and dumping 614 billion pounds of CO2 into the air every year.
That 145,000 tons of uranium the US has dumped into the air just by burning coal, since 1937? Well, that's 10440 tons of U235, which if you fission it (okay, with perfect effiency. This is just to illustrate a point) produces 17.6 kilotons of energy per kilogram. If you fission 10440 tons of it, you end up with 193 petawatt-hours. That right there's the electrical needs of the entire UK for 500 years, at present rates of consumption.
By all those metrics is nuclear power environmentally friendly. It's utterly ridiculous that we're not embracing the technology and making our electricity the right way.
, I could easily fire the weapon with no intent to kill.
Yes. That's what you're supposed to do. You shoot to stop a threat, not to kill.
Aim for shoulders, arms, or legs
Dear Lord, no, that's an absolutely horrible idea, and even if it works you just increased your likelihood of going to jail by quite a lot.
A handgun is not a weapon generally capable of precision fire in stressful situations. When you train to use a gun, you learn to aim at the target's center of mass, because this maximizes your chances of hitting at all. That 'aim for his leg' bullshit is exactly the sort of 'Hollywood portrayal that doesn't happen in real life' that you're griping about.
If you shoot that guy in the leg, then when you end up on the stand, the prosecutor is going to ask you why you shot him in the leg. It will be pointed out that if you honestly felt your life was in danger, you wouldn't have shot him in the leg, and that the fact that you did is evidence you weren't acting in legitimate self defense.
Bad, bad, horrible, awful, Hollywood-influenced idea. If you happen to own a gun, please go out and take a real self-defense course, instead of repeating what you see in movies.
What job? Protecting Western Europe from the Commies?
Only a fraction of total force strength is combat capable
And only a fraction of total force strength in Iraq is combat-capable. It's not like those 125,000 guys all are on the line with M-16s and M1A1s, and the other 1.2 million all have typewriters.
Maintaining the forces in Iraq plus their replacements in rotation has tapped out the US military.
It's putting a strain on transport capability, not manpower.
That's why enlistments are being involuntarily extended and chronically ill 55-year-old reservists are being called up.
Enlistments are always extended in times of war. Stop-loss orders are nothing new, and happened during the Gulf War. American military doctrine places reserve forces alongside regular units on the TOEs. That old reservist who got called up ha d a somewhat specialized skill that was in short supply: he was a psychiatrist.
Look, the IRR is not the bottom of the barrel, to be called up only as a last resort only when everyone else is spoken for. Our military doctrine regards it as an integral part of the force composition, to be used when it will be useful, and the fact that we re-activate people who are fulfilling their reserve requirements doesn't indicate that we've hit bottom.
He was calling up the IRR because it's been American military doctrine for decades that major wars will be fought by a cross-section of the military that includes the reserves; this dates way the hell back to the rebuilding of the armed forces and the reshaping of doctrine that took place in the aftermath of Vietnam.
You think if we needed those forces stationed in Blenheim somewhere else we couldn't, like, move them? Or would that leave the Fulda Gap wide open to hordes of Soviet T-72s?
Let me remind you, that all of that takes up our 1.4 million troops that we have
Of course it does. Even if we had 25 million troops, the three categories you mention would still take up all the troops we have.
"A. They are stationed in another of our many bases around the world."
Being an active member of the military means you're stationed somewhere. I mean, duh.
The signal spectra. In other words, the same thing that makes the signature of an explosion different than the signature of an earthquake. Hell, the Fast Fourier Transform was originally used for the very purpose of distinguishing between earthquakes and nuclear tests.
It's not humbling. It's just an indication at how grotesquely incompetent the mainstream media has become at reporting anything more significant than who got voted off the island.
Besides, "mushroom-shaped" clouds form from all large explosions, not just nuclear ones. Set off a big bomb, and you suddenly generate a large amount of superheated gas in a pocket near the ground. This rises so rapidly that it generates vortices around its perimeter, and the rolling of these vortices draws up a column of smoke and explosion debris, forming the stem. Then when the rising gas reaches a higher altitude where it's just about as dense as the surrounding air, it spreads out, forming the cap.
A mushroom cloud could be from a nuke. It could also be from the explosion of a liquefied natural gas storage facility, or a MOAB, or cargo train filled with ANFO. It's not a tell-tale of anything other than a big explosion.
It's more than just the US military that would know about it.
So would seismologists. Unless the US intelligence community recently clamped down on seismic research labs all across the free world, I'm pretty sure there'd be seismologists in various countries around the globe saying that they've recorded the seismic signature of a nuclear test.
Nowhere near "all of our troops" are in Iraq. We've got about 125,000 troops in Iraq. That includes Army, Marines, Air Force, Navy, and significant numbers of National Guard troops.
That's about two Canadian Armed Forces' worth of troops, but only a fraction of our total force strength.
And here's a big, big question for everyone who's going to bleat "Well why'd we send those troops to Iraq instead of North Korea?":
The city of Seoul is home to eleven million people. The city of Seoul is also within artillery range of North Korea. Artillery is cheap and ubiquitous, and as North Korea's army is arrayed along Soviet lines, they have scads of it. Until it fires, it's damned hard to spot camoflaged artillery from the air, and even if you could spot all of it, the sheer number of artillery pieces they have is quite staggering.
If you have a plan for military intervention in North Korea that doesn't lead to the virtual annihilation of Seoul within hours of the start of the war, please, we're all ears.
You're assuming there's life on Proxima Centauri.
No, I'm not. That was just an example. Radio allows us to look at a helluva lot more places than just Proxima Centauri.
We're not looking for ET here: we're looking for any sign of life
And SETI's looking for ET, not just any sign of life.
Don't you see that you've created a false dichotomy? For all the money spent on SETI, you couldn't afford even a single Mars probe. And SETI isn't stopping us from sending Mars probes. So why present this issue as you have, as a choice between either radio telescopy or physical search, but not both?
Again, look at the Mars missions.
I'm looking at them. I'm looking at hundreds of millions of dollars spent to "physically search" a tiny portion of the surface area of a planet that's about 50 million miles away.
The nearest star to earth, Proxima Centauri, is 24,698,699,219,682 miles away. Let's plug some numbers into the rocket equation, shall we? Vfinal = Vexhaust * ln(Minitial/Mfinal)) + V(initial).
Let's imagine some hypothetical chemical system that's way better than what we're using today, call it chlorine pentafluoride and hydrazine, something real messy, and end up with an exhaust velocity of around 4500 meters per second. Escape velocity from 1AU orbital radius is about 50 kilometers per second. If you want to "physically search," you need to slow down at the other end, too, so that's 100kps delta-vee.
100000 = 4500 * ln(x), solve for x, x comes out to about 4.5 billion. So to get a payload consisting of the Spirit rover's 175 kilograms to another star, you'd need to burn 787 billion kilograms of propellant.
Now, granted, for a more precise formulation you'd go to Newton instead of just algebra. But on the other hand, I'm also assuming a massless ship. And I'm not even considering how *long* the voyage would take, I'm just talking about getting up to escape velocity at one end and slowing down to avoid cratering at the other end. At 50 kilometers per second, to travel 4.4 light years would take 27,000 years. If you want to carry more useful payload, or you want to cover that distance faster, your fuel load goes up, literally exponentially.
I repeat: Sticking up a radio antenna lets you search a helluva lot larger area in a helluva lot shorter time, for a helluva lot less money, than "physically searching" does. The physical search you advocate is in no way, shape, or form technically or economically feasible at this point in time.
We're basically sitting here waiting for a message, when we should be physically searching.
This is silly.
Sticking up a radio antenna lets you search a helluva lot larger area in a helluva lot shorter time, for a helluva lot less money, than "physically searching" does. The physical search you advocate is in no way, shape, or form technically or economically feasible at this point in time.
'cause they have 3 billion neighbors instead of only 5.
Here's a though, RTFL. If you'd read the link you provide, and actually looked at the data as it is presented, you'd see that they break the challenges down by type of initiator, institution, etc.
So for "Institution," they show how many institutions challeneged were schools, school libraries, universities, theaters, public libraries, and so forth. They don't name specific institutions.
Which isn't exactly, or even close to exactly, what I was talking about.
Tool.