Slashdot Mirror
DOE Pumps $126.6 Million Into Carbon Sequestration
RickRussellTX writes "The DOE awarded $126.6 million in grants today to projects that will pump 1 million tons of CO2 into underground caverns at sites in California and Ohio. Environmental groups call carbon sequestration "a scam", claiming that it is too expensive and uncertain to be competitive with non-coal alternatives like wind and solar. I just hope nobody drops a Mentos down the wrong pipe."
This brought up Lake Nyos in my mind... What if all that CO2 escapes, indeed.
that's why all the plans involve putting it down somewhere.
If it was stored in gas form at atmospheric pressure, it wouldn't be a problem (it would just be silly). The problem is that if it's stored in highly compressed or solid form, then if something goes wrong and it goes back to gas, it *will* go up and escape, potentially killing anyone in the area.
Opus: the Swiss army knife of audio codec
If we run off of U235 plants, we'll run out of cheap uranium poste haste. The only way we know of to extend our nuclear fuel supply is to reprocess the U238 transmuted to plutonium (or thorium to U233) into additional fuel. However, this is readily achievable.
Conveniently, this sort of breeder reactor also has the ready potential to result in much more *complete* burning of nuclear fuel, resulting in much further reacted, and generally much shorter half-life products. The half life of breeder reactor waste can be as low as 100 years, and as the 95% of the enriched uranium that is U238 becomes viable fuel instead of being discarded as plutonium, the amount of waste per unit power drops by many orders of magnitude
Right now, India is the only country I am aware of that does extensive breeding (they're not in the Non-proliferation treaty, and don't have natively mined uranium, so they transmute thorium into fissile material) although France does some as well. The US doesn't do it because of proliferation concerns (which makes no sense to me, but whatever). However, since switching to a full nuclear power system requires going to breeder reactors anyway, it will also result in massively less waste (probably way less than coal power, and better contained), and shorter-lived waste.
You do know that plutonium can be used as a nuclear fuel? If it couldn't it would be useless for nuclear weapons.
Breeder reactors, reprocessing facilities and smart management can be used to dramatically reduce the amount of nuclear waste you have to dispose of - the figures I usually hear are somewhere between 95 and 98%. Also, nuclear plants don't constantly release radioactive particles like coal plants do. And they generate a lot of power. And the more modern designs are very safe; even Chernobyl required a risky test in an old reactor design conducted by a night shift crew that was unsufficiently trained.
Green power doesn't quite deliver as of yet. Photovoltaics still has a rather low efficiency and creates toxic waste during production of the panels. Hydro doesn't scale well, apart from dramatically changing the river you're working with. Geothermal only works in certain places. Wind also only works in certain places, doesn't generate that much power and is suspected to disturb bird populations and people living downwind.
The big question is: What do we do now? We can't go nuclear because that would mean we generate a few tons of nuclear waste per year that we have to bury for a few decades, apart from theoretically enabling teh nukes. We can't go coal because apart from CO2 emissions coal generates some nuclear waste as well. We can't go solar because solar doesn't generate enough power for most places and is toxic. We can't go wind and water either because they can't keep up with demand. We can't scale back our energy consumption either because that would be just as unacceptable as nuclear waste to most people.
At some point we do need to make an unpopular choice because there aren't any popular ones. I think that nuclear is one of the better choices we can make.
USE HOT GRITS WITH STATUE OF NATALIE PORTMAN (NAKED AND PETRIFIED)
Not quite, but you were on the right track. Basically in spent nuclear fuel you have three component groups. Leftover uranium, fission fragments and transuranics (heavy nuclei like plutonium formed when uranium absorbs neutrons ).
In a breeder reactor you constantly recycle the uranium and the actinides, so that the only waste product is fission fragments and activated reactor components. It is a lucky coincidence that virtually all the fission fragments that cannot be easily destroyed through recycling have either very short halflives ( less than 30 years ) or VERY long ones ( hundreds and thousands of years ).
The short lived ones decay to bellow uranium ore levels of radioactivity within about 300 years, while the long lived ones decay so slowly that they are less radioactive than the uranium from which they were made.
In spent fuel from traditional reactors you also have to worry about the actinides, and these cause trouble because they have half lives that are somewhere in between. This makes them radioactive enough to be much more toxic than uranium ore, but still long lived enough that they would have to be stored for hundreds of thousands of years. Breeder reactors split these into fission fragments that have characteristics very similar to the ones mentioned above, and therefore the waste decays to uranium levels within a few hundred years.
Also, in general it is worth noticing that if something has a halflife of X years then half of it will still be left after that time ( that is the definition of the radioactive halflife ). This is why it takes up to 300 years for the Cesium and Strontium components of fission fragments to decay bellow uranium radioactivity even tho their respective half lives are just a few decades.