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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'."
I applaud this kind of work.
Nuclear Power, despite the cries of environmentalists, is possibly the cleanest mass power source. On a scale of power generated per ton of input material it is incredibly efficient (bested only by those power sources which require no nonrenewable input, like wind/tidal/etc.), generates no effluent or air pollution, and needs only a competent staff (and, unfortunately, security), to stay running properly.
Nuclear plants may be prohibitively expensive to build these days, but if "pebble bed" reactors cost significantly less, then they may lead the way back towards what I view as our ideal energy source.
It's time to give nuclear a second chance.
It's how to handle the waste. That represents a real engineering challenge - some of that stuff is going to remain toxic for tens of thousands of years. Not only does it have to be stored safely and securely, but you have to work out some way of marking it so that should anyone stumble across it in a couple of thousand years, they understand not to touch it. The amount languages and cultures change, you can't just write on it, and even things like skull pictures could be interpreted as meaning "burial chamber - archaelogists, get digging!".
That said, I'm not against nuclear power (from fusion) per se. Of the options we have, it's one of the best at the moment. "Alternative" power sources need a lot more work, and fusion, whilst extrememly promising, just isn't practicable yet (unless I've missed a major breakthrough in the last couple of years). I'm just pointing out that there are still other problems that need to be addressed.
It's official. Most of you are morons.
I think it is important to move away from the current reliance on fossil fuels as quickly as possible and move towards nuclear power generation as the only realistic sustainable alternative power generation scheme.
Many of the world's problems exist because of the small patch of oil-soaked land out in the Middle East and the lack of trustworthy stewards of those fields. With Gulf War II over and those oil fields finally in the hands of Western democracies we may see some improvement in global stability vis a vis the opening of OPEC to its main customers. However, because we continue to rely on oil as our primary power source we will likely continue to have problems as the oil fields run drier and drier.
It is good to see Africa (of all nations!) take the lead in this new system of nuclear power generation. Older systems like the ones in Canada and France are fine, however it would be a stretch to say that they are perfect. There is plenty of room for improvement in those power plants. This usage of uranium pebbles is one such improvement, but there are more.
It is a problem that people would be willing to block the development of Africa because they object to the usage of these newer power systems. Especially so because for the most part the same protesters unwittingly reap the benefits of their own country's nuclear power generation systems.
The perennial question is one of waste disposal. It's all very well having a realtively clean source of energy right now, but if you have to guard against people getting hurt for X years, where X is a very large number...
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They claim the graphite and silicon carbide around the pebbles will keep it sealed for ~ 1 million years, which is impressive. It'll be interesting to see if humanity is around in ~1 million years
It also produces about 19 tons of radioactive waste (in the form of these coated pebbles) every year. That's going to be some landfill site, if the technology takes off...
Simon.
Physicists get Hadrons!
Reading some of the comments in this article, I have to wonder when 'Geek' and 'Nerd' transformed into 'Reactionary Luddite'.
Yeah, disposal is a problem.. but it's not like it wasn't just lying around to begin with.
Oh please.. that old, tired argument again. YES, uranium occurs in most rocks in concentrations of 2 to 4 parts per million and is as common in the earth's crust as tin, tungsten and molybdenum. HOWEVER, uranium in the natural state is a mix of two isotopes; 99.3% U-238 and 0.7% U-235. And guess what? U-238 is barely radioactive, with a halflife of about 4500 million years. U-235 on the other hand is way more radioactive, and thus the part they are interested in using for reactorcores.
Guess what? The enriched uranium they use in reactors contains in the region of 3% to 4% U-235 - making it litterary too hot to handle. Even 'spendt' reacorfuel contains more U-235 than ordinary oranium-ore, as well as more than a bit of Pu-239 and Pu-240 (the longer the fuel stays in the reacor, the more Pu-240). And Pu-239 and Pu-240 is two isotopes of an element better known as plutonium... granted, it's not weapongrade plutonium, but it's still something I wouldn't have scattered about.
Fact: There is little or no pollution from an operative reacor.
Fact: Spent fuelrods from reactors are a major enviromental problem.
You might find this and this webpage interesting.
Everything in the world is controlled by a small, evil group to which, unfortunately, no one you know belongs.
No not really, the parties behind the S-African reactor are the same ones as were behind the Hamm-Uentrop fiasco, which by the way is only 13 years old. And the Germans at least have significantly scaled down their interest in the technology. By the time construction started Hamm-Uentrop drew on 20+ years of research and testing. Even so took 3 times as long to build as planned, it went way ahead of budget and due to amont other things fuel handling problems never functioned 100% reliably. So if the S-African reactor is based on German PB-reactor technology which has not evolved much since Hamm Uentrop due to lack of funding I rather think these people are trying to restart development of a troubled technology in a place where they think resistance will be weaker. They are betting the S-Africans will allow them to do something that would have the Europeans picketing by the thousands at the construction site faster that you can say "pebble bed".
Only to idiots, are orders laws.
-- Henning von Tresckow
Guess what? The enriched uranium they use in reactors contains in the region of 3% to 4% U-235 - making it litterary too hot to handle. Even 'spendt' reacorfuel contains more U-235 than ordinary oranium-ore, as well as more than a bit of Pu-239 and Pu-240 (the longer the fuel stays in the reacor, the more Pu-240). And Pu-239 and Pu-240 is two isotopes of an element better known as plutonium... granted, it's not weapongrade plutonium, but it's still something I wouldn't have scattered about.
Sure, we "enrich" the uranium-- largely by sorting isotopes. There's no reason why you couldn't choose to de-enrich/deplete the uranium back down for storage, if you thought this was beneficial. This is why it's entombed in glass in many storage proposals, and why it's often reprocessed-- so you can sort the "useful fuel to reuse" and "spent fuel/waste".
There are intermediate-term (80-500 year) storage problems involved with the high level wastes produced in fission reactors. The thing is, these wastes inherently have short half lives and decay to more harmless stuff very quickly.
Chernobyl had a lot of things that were just wrong.
The reactor increased in efficiency as temperature increased. This is a nice little feedback loop. Most reactors lose efficiency as temperature increases, meaning that it is difficult to try and overload the reactor, even on purpose.
The reactor was designed to be cheap, and it did not have a dome. Domes contain radioactive material very well. Tests have shown that an aircraft hitting a dome would hardly scratch it.
As another cost-cutting measure, the reactor didn't have any good backup power. It may seem silly to have a power plant that needs power, but nuclear power plants do need power to start up and in case of emergencies. Western plants have batteries and generators.
As if these technological blunders weren't enough, some bonehead transfered control of the power plants from the ministry that designed and built them, where all the trained personnel are employed, to the ministry of energy. There are reports of operators sitting on the control board and people showing up to work drunk.
Basically, in 1986, the Chernobyl reactor demonstrated a bunch of "don'ts" to a world that should have already known.
There will always be technology out there that can be misused. The amount of that technology will only increase. Do we ban knives because people get stabbed? Do we ban nuclear power because a couple of Russians cut costs?
The 'ball' nuclear reactors are basically foolproof. You put a bunch of balls next to each other and you get heat. This is not weapons grade Uranium.
I only see one problem with nuclear -- the small amount of waste that is generated needs to be handled properly. It can be done, but it just has to be done right.
Fact: There is little or no pollution from an operative reacor.
Fact: Spent fuelrods from reactors are a major enviromental problem.
Fact: The byproducts of all other currently viable forms of energy production are major environmental problems.
I can't think of anyone who would say that nuclear waste is not bad. But I for one, and many others who have researched the topic, believe it is less bad than the alternatives.
I would rather have a small amount of really bad stuff being controled, than a huge amount of pretty bad stuff being spewed into the air I breath every day.
"I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...
True, if you only consider what is legally released into the environment while the nuclear plant is operating. If you consider the fission byproducts and their "disposal" (e.g. long term storage) then this isn't true. Yucca Mountain nonwithstanding, the problems associated with nuclear waste may not be worth the benefit (and I'm a nuclear-trained engineer).
I think a lot of us fall into a 'middle-ground.' I'm fearfull of the long term effects that plant melt-downs have. . . but at the same time I realize that there potentially are safe(r) designs. If someone can truly come up with a 'disaster proof' reactor design that doesn't produce highly dangerous waste (it sounds like the design you mentioned is a likely candidate) then I'm willing to at least consider them.
Safe designs for nuclear reactors actually kind of excite me, because we clearly need to get away from fossil fuel energy.
Although, ultimately, I'm most excited about bio-mass energy (if it can ever be made to be practical at a large scale), because while burning bio-mass derivative fuels produces CO2 - at least the next generation of fuel will re-fixate that CO2 as it grows. . . it's a stable system where we are at least not increasing the amount of CO2.