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Megatons To Megawatts Program Comes To a Close
necro81 writes "In the aftermath of the Cold War, the disintegrating Soviet Union had tens of thousands of nuclear weapons and tons of weapons-grade fissile material. In the economic and political turmoil, many feared that it would fall into unfriendly hands. However, thanks to the doggedness of an MIT professor, Dr. Thomas Neff, 500 metric tons of weapons grade material made its way into nuclear reactors in the United States through the Megatons to Megawatts program. During the program, about 10% of all electricity generated in the U.S. came from weapons once aimed at the country. Now, after nearly 20 years, the program is coming to an end. The final shipment of Soviet-era uranium, now nuclear fuel, has arrived in Baltimore."
The warheads were only Megatons because they were fusion weapons.
We only used the fission trigger part to generate power'
Your pedantry is misplaced: your error is thinking of the warheads individually.
Instead, there were ~20k nuclear warheads worth of HEU involved (500 metric tons). Since even the inefficient gun-type Little Boy weapon had an estimated yield of 15 kt for 64 kg of HEU, the program represents a minimum of 120 megatons worth of yield—even falsely presuming they couldn't achieve better yields with that HEU than using a gun-type weapon approach.
The program's name is perfectly cromulent.
The pollution from coal waste is permanent, it never decays unlike nuclear waste. US coal-fired power generators pump 50 tonnes of mercury into the environment every year, it never goes away or decays, it ends up in water and the soil, in the sea and seafood. Nobody cares, any attempt to reduce these sorts of emissions is a "War on Coal".
That mercury WAS buried underground well away from the biosphere. Now it's been dug up, burned, vapourised and spread over cropland and towns and cities downwind, deposited into rivers and lakes supplying drinking water to the population before it eventually makes its way into the sea where it bioaccumulates in fish to the point where authorities recommend people don't eat too much of it because of the toxic mercury content.
You might want to look up "sequestration" sometime.
It's not a small amount - it's a long process and it's not just the depleted fuel that's a waste storage problem. Anything that gets bombarded with a lot of neutrons becomes nuclear waste itself, so. That's what the "nuclear is magic beans appearing in the reactor core" crowd don't get. That's why real solutions like Synrok were ignored for decades.
The health problems start with water runoff in the mines (eg. acid mine drainage), just like a lot of other things. Nuclear is not magic just because it's nuclear.
It's an industrial process that has impacts and benefits and has to be looked at that way instead of the stupid "clean" dream. We got over "duck and cover" and "too cheap to meter" - it's time to get over the "clean" propaganda as well.
The warheads were only Megatons because they were fusion weapons.
No, this is a common misconception.
A basic nuke compacts a lump of (e.g.) plutonium to above the critical mass using convential explosives. The momentum caused by the explosives holds it together while the chain reaction grows exponentially. Eventually it flies apart, generally before the fission fuel is used up because the explosives don't hold it together very long.
You can introduce fusion by hollowing out the pit and filling it with tritium, giving a boosted fission bomb. That boosts the power a bunch (yay!).
However, the thing to note is nuclear explosions are much bigger than conventional ones, and if a conventional explosion is good at holding the fissile material together, then a nuclear one ought to be much better, and it is.
So basically, you pack lithium deuteride around another fissile pit. When the nuke goes off, it irradiates the deuterium creating tritium and compresses the second pit giving another nuclear explosion. It's a much more efficient one second time since it's held together longer and you also have much more tritium, so both the fusuion and fission but yield a lot more energy.
At this point you have two relatively small fission explosions, one mid sized fusion one and one large fusion one. Most of the energy comes from the fusion. It's also relatively clean in that the amount of nasty byproducts to energy ratio is low.
The logic continues. It a small fission explosion is really good at compressing, then a large fusion/fission one ought to be REALLY REALLY good. A third stage can therefore be added (allegedly this is not usually the case).
But it still doesn't usually end there. The nuclear reactions yield what is technically known as an ass-load of neutrons. If you wrap the entire thing in natural or even depleted uranium, the neutrons cause it to undergo fission. Lots of fission. It's generally thought that this stage more than doubles the yield and comes at next to no extra cost, size or weight (the bomb has to have some sort of heavy casing anyway).
Anyway, that's a summary of the wikipedia article and a few other bits and bobs.
TL;DR in most cases a bit over half of the energy comes from fission.
SJW n. One who posts facts.