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Uranium Pebbles May Light the Way
kristy_christie writes "According to Wired News, South Africa's state-run utility giant Eskom and its international partners want to build the world's first commercial 'pebble bed' reactor, which, instead of using fuel rods, 'is packed with tennis ball-size graphite "pebbles," each containing thousands of tiny uranium dioxide particles'. To developers, the Pebble Bed Modular Reactor promises a rebirth of nuclear energy. Proponents insist that the reactor's design features make it 'meltdown-proof' and 'walk-away safe'."
We (USA in the 90s) promised two of these (or very simiar to these) to North Korea so that they a) could have plenty of power and thus might spend money on economic growth/feeding their people and b) couldn't develop nuclear weapons from the material. but oops, congress wouldn't approve it. Now look where we are with them. big mistake
though many popular activists site environmental reasons as opposition to nuclear energy, disposing of nuclear waste really isn't that difficult. Most scientists (at least those in the field) object to nuclear power because of the potential of the spread and proliferation of weapons. while environmental issues ARE a concern (there's always some governmental dweeb that screws things up), it is something that can fairly easily be isolated given the proper precautions. Part of the reason that these reactors get so much attention is that these same experts have much fewer qualms with them precisely because they are so much more difficult to make weapons-grade uranium/plutonium from. (i cite Howard Margolis, Dealing with Risk as a decent summary of this topic).
burying it deep enough is the key(so that it's not too probable that anyone with brains will just accidentally stumble upon it while on a picnic, also at relatively not too deep there's natural radiation also so that anyone who would dwell there would need to have the brains to protect himself anyways), or wait till we can send it to the moon/sun/mars/alfa centauri(50-400years.. if there's not a huge nuclear ww3 before that and then i wouldn't worry about nuclear waste).
burying it deep in some stable part of the earth is the best way currently though(at least much better than the sometimes used method of just stacking it in a shack). and besides, ancient egyptians got their cursed tombs, WHY CAN'T WE HAVE THEM??!?!?-)
however, we have much bigger waste problems than just nuclear waste.
world was created 5 seconds before this post as it is.
As far as I know there are no international treaties banning breeder reactors; the bans that exists in the US for example, are internal to the country.
Maybe it's time to reconsider those bans, as it is becoming quite apparent that there is no near term solution to the energy problem apart from nuclear energy and there is no other good way to handle nuclear waste.
I would like to see the Department of Naval Reactors, in conjuction with the Department of Energy and the U.S. Navy be contracted to design, build, man and run nuclear power plants for commercial power consumption. Then turn around and sell that power to the utilities companies.
They already buy power from one another on a regular basis and the more importantly the track record of the U.S. Navy in Nuclear Power useage is impeccable. The training program, security, design protocols, safety record and tradition of excellence make them the only people in the world I would trust 100% to run a nuclear power plant.
Another problem with pebble-beds is that they use natural or low-enriched uranium in a cycle where the fuel passes through the reactor relatively quickly and continuously (no big refueling outages). This makes them ideal Plutonium factories, which is obviously a matter of concern. Most of the graphite-moderated reactors ever built were designed primarily to produce Plutonium, including the Soviet RBMK's and the piles at Sellafield.
Don't get me wrong - I'm all for nuclear power for many reasons, but I'm not sure the pebble bed is that much of a breakthrough, and I don't think graphite is the best choice of material. And any operator of a plant in trouble that went home for the weekend should be shot. "Walk-away safe" my ass.
Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
And generate all sorts of weapons-gradd material in the process. It's a major proliferation risk; that's why the U.S. has not chosen that option.
Nuclear waste simply is not a significant reason not to use nuclear power. The only problem is what to do with old, worn-out reactors.
There's another little reason: the risk of terrorist attacks on the plants. People argue all day about the technical safety and waste disposal issues. However, the security issues of proliferation and terrorist risks are by themselves enough to make avoiding nuclear power a no-brainer.
Our president has been running around hysterically shouting about WMDs for several years now. What's one of the most significant sources of material WMDs? It's when 2-bit countries convince people to let them have their own nuclear reactors. Again and again, we find out that they start producing weapons materials as soon as they crank up their plants. Part of the "war on terrorism" should be developing energy sources that allow us to totally eliminate nuclear power with its fuel cycle that has allowed several countries to hide their nuclear arms programs. Not to mention the problem that nuclear plants in your own country allow someone to turn a truck bomb or an airplane into a WMD (and don't bother bringing about the 3-foot thick shield around the reactor; I'm talking about attacking the unshielded spent fuel storage ponds).
Whatever happened to vitrification? Mix the stuff into glass, cast into handy-sized lumps, bury in moist earth, post a guard to keep the bad guys from digging it up. As deep as they want to bury it, any post-catastrophe society capable of reaching the stuff should be developed enough to figure out that it is dangerous, particularly since, unlike natural ores (which are also dangerous), the stuff will be *marked*.
Also, we've done well with Reduce and Recycle, but how are we doing with Re-use? It seems to me that much rad"waste" is just a resource for which nobody has tried hard enough to find a use. Medicine, nondestructive testing, long-term preservation of organic matter, etc. all have uses for long-lasting sources of radiation. (I tell my kids to remember where the landfills are, because their grandchildren will want to mine them.)
the problem that most people have with nuclear power is tchernobyl(or similar catastrophy that would release radioactivity to a wide area).
I'm glad you mentioned Chernobyl...
'is packed with tennis ball-size graphite "pebbles," each containing thousands of tiny uranium dioxide particles'... Proponents insist that the reactor's design features make it 'meltdown-proof' and 'walk-away safe'."... because apparently these people haven't learned anything from it.
The most important lesson of Chernobyl is that graphite burns. So if you lose control of this thing, it will catch fire. And the fire will spread radioactive decay daughters all over the place.
I am a big proponent of nuclear power, but only of one design: CANDU (CANadian Deuterium-Uranium). It's inherently impossible for it to melt down. It uses U-238 (natural uranium, in the form of "ceramic" pellets of uranium dioxide) which is NOT capable of a chain reaction without a heavy water moderator. (Heavy water is just water where the hydrogens have neutrons. Non-radioactive, naturally occurring, and just slightly heavier than normal water.)
As a result, if you lose control of a CANDU reactor, the reactor will overheat. Pressure will build up in the heavy water system until something breaks. The moderator will escape as steam, and since the fuel is essentially non-water soluble, with only extraordinarily small trace amounts of radioactive materials. With no moderator, the chain reaction stops, and the reactor cools down. This process occurs as a result of the laws of physics; in other words, Chernobyl cannot happen at Pickering or Darlington even if all the control systems fail or someone goes to extraordinary lengths to circumvent them.
The other great lesson is not to let boobs run the reactor. All nuclear power programs have had problems with this in the past; a "walk away" approach simply encourages this.
Fire and Meat. Yummy.
I don't think I'd want to carry it around as a good luck charm, though.
Well, reprocessing "spent" fuel to get the unconsumed U back was what I meant by "recycling". It's a good idea and, if we can do it right, we ought to do it.
By "reuse" I meant take the stuff that's no good for large-scale power reactor fuel and use it for something else. Like sterilization or probing metal castings for flaws. And if all else fails, someone else pointed out that the gunk still produces quite a bit of heat -- not enough for a commercial electric plant, but maybe enough for something that has to sit in an inaccessible place for decades without resupply.
Hydro...yeah, come to Indianapolis and ask the old-timers where Dandy Trail is. (It's at the bottom of a reservoir now, not such a fun place to go anymore.)
Stuff like solar, wind, tides, etc. can be stored as compressed air, used to extract hydrogen from water, pushed into high-performance flywheels, etc. so batteries are not necessarily needed.
Tidal generation might actually be a good thing for e.g. the barrier island systems of the North American east coast. Hmmm.
Oh, and coal mines are hard to clean up too. Ask about all the acid runoff. Ditto the mines that produce whatever materials go into your favorite alternative energy source.
We could boil all this down pretty compactly: energy production is messy and dangerous. So's millions dying of cold or fighting the wolves off with sharp sticks, though.
You are mistaken.
A nuke plant produces about 6.5 ounces of waste per minute, or about 20 tons per year for a typical thousand megawatt plant. A single coal plant produces about 10 tons of waste per minute, or about 300,000 tons of waste per year. Since the radioactives don't burn, they get concentrated in the ash. That thousand-megawatt coal plant releases about 20 tons of uranium and thorium (alone) from the 4 million tons of coal it burns.
All waste is an "emission", whether it literally goes up in smoke, is stored on site, or gets bundled into bricks and hauled away by truck. The only question is in what form, and where and how you transport it and store it.
Where do you think all that coal ash goes? They retain most of it at the power plant and bury it -- just like nuclear waste. Some of it gets made into building materials. The FAS estimates there are 2000 additional cancer deaths per year from radioactivity from the 5% of coal ash incorporated into building materials; it would be 40,000 if all the ash were used.
You can imagine the panicked public reaction if nuke plant waste were spread out by diluting it with a lot of neutral material and built into people's houses.
And, of course, the non-radioactive toxins from coal, like lead, cadmium, mercury, and C02, remain toxic forever, with a nearly infinite half-life.
There's no funny accounting going on here, with the coal emissions being counted while all the nuke emissions are ignored because they're stored at the plant, as you suggest. The radioactive emissions from a coal plant are indeed about the same as the total waste produced from a nuke plant. But then you have to pile on all the other waste from those fossil plants. Nuclear plants are cleaner, in total, and surprisingly not even any messier when it comes to radioactive waste alone.