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China to Pioneer Melt-Down Proof Reactors
pease1 writes "FT.com reports China is poised to develop the world's first
commercially operated "pebble bed" nuclear reactor. If successfully commercialized, the pebble bed reactor would be the first radically new reactor design for several decades. It would push China to the forefront of development of a technology that researchers claim offers a new "meltdown-proof" alternative to standard water-cooled nuclear power stations." This was mentioned in September of last year but now looks as though the plan is moving forward.
Funny how it is, generally speaking, the same group of people who berate the US for our dependence on mideast oil, while at the same time vehemently protesting any movement down any path that might actually allow us to realistically release ourselves from some of that dependence, e.g., new nuclear plants. But no: must ... be ... scared ... of ... anything ..."nuclear" (including things like Cassini...)
Face it: from a standpoint of physics, wind, water, and solar, and the mechanisms for extracted energy from them, are NOT ENOUGH to sustain any semblance of the current lifestyles, right or wrong, without drastic and dramatic changes that would have far-reaching economic and social implications. We need to REPLACE the power sources we aim to wean ourselves from. And nuclear is the answer. Yes, there can be conservation. Yes, there can be debate. Yes, there can be compact fluorescents and LEDs. But those will only affect so much. Our energy requirements, as well as those of the rest of the world, are growing, and we should be leading the fucking way on the front of nuclear power, INCLUDING fusion, building new plants, and making a lot of investments in this area.
And we're simply not doing that. Fuck it: people say Social Security is the "third rail" of American politics? Energy policy is the power plant that electrifies it.
Perhaps China's communist regime has an advantage after all: they can actually do things that will be GOOD for their country, like building nuclear power plants without endless ranting and raving from protesters, and storing waste safely in places like Yucca Mountain (because having waste at ~150 temporary, insecure facilities is certainly better than having it at one site, imperfect as it may be).
While this is a worthy achievement, and will certainly ease a lot of fears about third world countries operating reactors.
Unfortunately these reactors will still produce quite a bit of waste, and will still need to be decomissioned. Given how poorly the western world handles these issues, i can't imagine how well it'll be done elsewhere...
is there any diffrence in the ammount of waist produced? Being assured that it wont melt down or spin out of controll is good, but to get past the anti nuke arguments it'll have to be at least a little cleaner.
Paying taxes to buy civilization is like paying a hooker to buy love.
"If you don't like this nuclear facility next to your rice paddy, you can go to jail."
As China's growth continues to surge, there will be more examples of China taking the lead in things- both good AND bad. When the government can tell you what to do (or else), things get done.
I am not an alarmist and I do believe that nuclear power can be safe BUT does anyone else get that deja vu, creepy music in the background, the monster is RIGHT behind you feeling whenever any one says something is *-proof?
Just me then? OK.
I don't think, Therefore I'm not.
So would the worse-case scenerio in a meltdown in China be called "The America Syndrome"?
Somedays I'm convinced that China will become the sole economic superpower in the world in our lifetime. The US may still have a powerful military decades from now but it really looks like the Chinese want success more than we do. The fact that they are moving ahead with nuclear power is an example. Here in the US, you just can't get any kind of nuclear power plant built. We continue to use rediculous amounts of electricity but resist any attempts at becoming self-sufficient. The Chinese are hungry to improve their country while we Americans have become complacent and feel like we will always be on top. Once our debt gets to the point that other countries will no longer invest in us, we'll sink like a stone and China will take over (economically). They just want success more than we do.
GMD
watch this
just like england pioneered the unsinkable ship?
This is truly sad. Not to be a troll or anything, but the only reason we are not seeing a massive reduction in the amount of foreign oil we depend on, or improved air is because of the stigma attached to the world "nuclear".
So, we continue to use oil and coal.
For those of you who don't know, pebble bed reactors will allow for the increased use of the radioactive elements until they pose no significant threat. To use an analogy, the battery is almost completely drained. Also, they are inherently safer due to improved design. Their default position is one in which the reactive elements are in no position to cause any sort of melt-down.
But hey, it has the word "nuclear" in it, so it has to be bad, right?
Buncha tree-hugging softies.
I'm out.
In my opinion, one of China's greatest assets is its lack of current infrastructure. Imagine being able to design roads, dams, bridges, electricity generating plants, etc with 2005 technology without having to support an existing infrastructure.
We're going to hear more stories of bullet trains, monstrous dam projects and now advancements in nuclear energy production.
Good for China - start investing in them now.
I'm a big tall mofo.
Here is the better article from Wired all about these types of reactors.
m l
http://www.wired.com/wired/archive/12.09/china.ht
Won't somebody please think of the dinosuars?!!!
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
For alternative fuels this century. While the United States continues its 'fight' for fossil fuels in the middle east, they will be spending their budget to completely remove themselves from the shackles of fossil fuels.
just IMAGINE where we would be if we spent that $280 BILLION on the Iraq war funding technology to develop alternative fuels? When will we realize that fossil fuels are such an impediment and where we could get if we got real about losing the middle east (oil)?
Lawrence Person (lawrencepersonh@gmailh.com (remove all "h"s to mail)
http://www.lawrenceperson.com/
If we can build safe, pebble-bed nuclear reactors, GREAT! However, before we start up construction, the same problem that plagues conventional reactors exists; what are we going to do with the waste?
Even if Yucca Mountain (or some other ground storage facility) happens, it's years and years away, and it seems foolish to continue to generate nuclear waste with no place to put it.
Speaking as a US citizen *we* want success but some of *us* will shout down and protest any and all attempts to research and/or build Nuclear Reactors.
Europe wants success too. But they measure success as everybody gets a comfortable living, everyone is cared for and no person goes hungry.
Remember, one of the most successful countries of all time was Nazi Germany.
Not just China. I know someone who has just accepted a job to help develop a pebble bed reactor in South Africa. And he is not a nuclear scientist but an electrical engineer: i.e. they are actually building something. See also http://en.wikipedia.org/wiki/Pebble_bed_reactor
Paul Beardsell
Umm. Candu reactors shut down when they lose coolant because the coolant is what sustains the reaction. I'd say thats meltdown proof. They can crank out a heck of a lot more power than a pebble bed reactor because a pebble bed reactor creates less heat - unless thats what they are working on fixing.
We have gone from having the most enviable public school system in the industrialized world to having the flat-out worst.
We don't invest in infrastructure, we don't protect our borders from illegal intrusion, we don't care about pollution or graft. As long as we can have the appearance of wealth...not to be confused with legitimate wealth which is grown, not borrowed.
I agree, the US is over as the preeminent power, its just going to take time for people to realize it. Around 2030 when China and the US face off probably in the Middle East for the remaining easy oil, Americans will get a rare taste of what war is like from the losing side.
> net negative sources of fuel
:P
God, when will this myth stop propagating? They haven't been net negatives since the 1970s; and of the dozens of studies done since then by everyone from the DOE to various universities (essentially all except anti-ethanol crusader Pimental) have shown a 30-50% positive energy balance, and with current tech it may be able to scale up as high as 70%.
Furthermore, even if it were a net negative, this is completely irrelevant. Example: During WWII, the Germans made petroleum from coal. This was a costly process that used many times more energy to produce the oil than the oil contained (they burned much of the very coal that they were converting in order to power the conversion). And yet, it largely fuelled the Nazi war machine.
The issue is converting a *non-mobile* source of energy to a *mobile* source of energy that you can put into your gas tank. If an ethanol plant takes in grid power, it's eating mostly coal. If it doesn't use grid power, it's most likely burning ag waste or other local non-mobile sources of energy. It's not like they're burning ethanol to produce ethanol
Of course, this is all irrelevant: Ethanol *IS* a net positive.
Dear Lord: One of your creatures may be hurt tonight. Please let it be the other creature.
Not in my backyard and all that.
So you're saying, then, that it's better for our nation as a whole to have waste stored in unmonitored, insecure, and in some cases failing, storage containers and sites at over 150 locations randomly scattered around the country, indefinitely, than in one place that is at least quasi-permanent?
And why do I have to live within visual distance of a nuclear power plant to (correctly) say that it's a very compelling answer to our power problems? Possibly because nuclear power has been so vilified by some people that others are irrationally deathly afraid of it?
Your argument is extremely poor, because:
1.) It's based on "non in my backyard", and,
2.) You make a fallacious argument that living closer to a power plant somehow makes one more able to comment about nuclear power.
The fact is, the city where I live doesn't have a nuclear power plant. Frankly, I wish it did.
Good job using nothing more than scare tactics to frame your argument. Why, exactly, would it be bad to live close to one of the 104 operating nuclear plants in the United States?
Because of irrational fear and nothing more?
Or perhaps we should eliminate nuclear power altogether! I'm sure that would help us down the road to solving our energy problems!
Should this spread from China to the increasingly energy-hungry South Asian and African nations, will it have to be as heavily controlled as conventional reactors? Is it possible to use a pebble bed reactor to create weapons grade uranium or plutonium?
Where did you get those numbers?!
;-)
Brazil runs a very successful ethanol program for many years now. It had a low a couple years ago, when engines running on gasoline had a technical edge (largely due to imported vs homegrown technology issues), but now most factories (GM, Fiat, Volkswagen) offer cars with dual fuel engines. In fact, since 1986 I only had two fossil-fuel running cars. My current one has never even tasted gasoline
True - ethanol still creates CO2, but at least you can grow it on the field and hope it absorbs a lot of CO2 before you harvest it.
I think if ethanol was that bad a fuel we would have noticed that by now.
http://www.dieblinkenlights.com
The war on terror has been an incredibly useful device for the Republican party...they get to broaden their appeal to military types and flat-out bigots, they get free reign to pillage Alaska for a miniscule amount of oil, they get to paint criticism as "unpatriotic", and they get to defer serious debate because of course "we're at war!".
They wouldn't get any of this out of alternative fuels research, and to boot they would lose the oil and military graft dollars that got them there in the first place.
Sorry, wouldn't work!
Since this is slashdot, I know your post will probably be modded to +5.
Let me just say: is it possible that traditional energy companies don't just *adore* nuclear power (or ANYTHING that cuts into their profits)? Sure. Absolutely.
But there is no organized conspiracy by ANYONE in the industry to foster a fear of nuclear power. There didn't need to be. The anti-nuclear activists and some (not all) of the environmentalist movement have done that all by themselves.
Well, you'll be glad to know that the Chinese pebble reactors will, more than likely, not encounter any icebergs.
--- Ban humanity.
Calling pebble beds "meltdown proof" is really a stretch.
First off, meltdown aside, their moderator is *graphite*. Their emergency cooling scenario is that air will cool the reactor. Nice, except for the fact that even nuclear grade graphite will burn in extreme conditions quite fiercely (it was the burning graphite, more than anything else, that spread the radiation from Chernobyl). Hot graphite also produces explosive hydrogen gas in contact with water (in fact, many of these plants are going to be designed to produce hydrogen from water, so we know it will be present, even if in a different loop).
The very concerning thing is that they're so confident about them that they're not planning to build containment structures. Pebble beds are a nice design, mind you, but they're not *that* safe. A single graphite fire starts, and you've got another chernobyl that destroys a large swatch of land (it's not the casualties from nuclear events that are the problem, but the land rendered uninhabitable). Nuclear accidents have been, unfortunately, surprisingly frequent; it's the containment structures that have kept the danger that they pose limited.
Then, there's the problem with the pebbles themselves. Even in normal conditions, the German prototype experienced pebbles jamming. The safety against meltdown for the pebbles is that their expansion coefficient is designed to reduce the rate of reaction of the fuel; however, if the pellets jam against the sides as they expand, this safety won't help. This may or may not to prove to be an actual problem, of course.
I'd much rather see them go with a lead-bismuth breeder. It's a breeder (so you can utilize more fuel), it produces less waste, the waste is easier to handle, it's anti-proliferation, there's no graphite, there's no pellets to jam, etc.
Dear Lord: One of your creatures may be hurt tonight. Please let it be the other creature.
The titanic is unsinkable
...nuke waste can, for the most part, be recycled. The media, however, is too busy playing boogeyman, and leading us down the path to being a 4th world country with horse drawn wagons and biomass generators providing citizens enough electricity to light a 20W bulb.
--- Ban humanity.
I think the CANDU reactor is inherently more meltdown-proof than this design. The CANDU reactors use heavy water as both the moderator and the coolant - if you lose the coolant, you also lose the moderator, so the reaction stops. The only bad situation would be if the coolant pumps stopped moving the coolant, but then you could dump the heavy water manually, or just wait for it to flash to steam and get sucked into the vacuum building that sits beside the containment building. Either way, the reaction stops before it gets to a "meltdown" point.
The next Cmdr Taco duplicate will be ready soon, but subscribers can beat the rush and see it early!
Imagine one peb cracking, and depositing the stuff on the bottom of the bed, which reacts more strongly with a few more pebs, causing a hot spot and some convection, which can crack more, etc.
Some things that seem to be missing from the popular accounts: just what the pebs are coated with, how tough they are, and how long they are supposed to hold up to constant expansion and contraction.
Sometimes seventeen/Syllables aren't enough to/Express a complete
I should preface this by saying that I'm not opposed to nuclear power generation, and that I think that the newest generation of reactors (especially those using pebble beds) are very promising.
Still, I'm wary of these sweeping, blanket statements people tend to make about new technology. Remember how electricity would be too cheap to meter? Remember how Vioxx easily secured FDA approval? How the Space Shuttle flew for years with bad O-Rings?
I'm not a luddite, and I'm all for progress -- even when it's dangerous. But people are making sweeping statements about the safety of this new generation of reactors. What about spent fuel? What about issues that we don't fully understand yet?
We have a long track record of giving lay people the rosiest possible picture of progress. Then something goes wrong. The SL-1 Reactor, Three Mile Island, Chernobyl, others. The public gets scared and recoils. And then we're surprised when they balk at a new generation of "meltdown proof" reactors!
I'd like to see the PRC try these reactors out for a decade or so before I approve the operation of one in my backyard. Remember the consequences of missteps -- entire regions of the country made uninhabitable for generations. The risk may not be great, but the consequences are.
That's simply not correct. It was true decades ago when the only source of biomass being used was food-grade crops - current industrial agriculture is massively inefficient. Current biomass production, primitive as it is, is net positive.
Uranium and Plutonium are both highly toxic. Supplies of U-235 are limited. Plutonium presents massive security issues.
Costs of both photovoltaic and wind are falling. When external costs are figured, they're cheaper than coal or nuclear.
So stop with the FUD already, ok?
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
Fortunately I just read about the term "unsinkable" as it was applied to the Titanic. The boat-maker never used the term. The dock-workers never used the term. The buyers never used the term. The only one who used it was a marketer for a travel agency booking berths aboard the Titanic. No one, the captain included, thought the ship was unsinkable. The very idea is ridiculous. Pour enough water into the ship, and it will sink.
On the other hand, pebble-bed reactors do not rely on making it difficult to meltdown, they rely on the fact that the natural state of the reactor bed is a "safe" condition. (No, that doesn't mean you can stick your head in it, just that it will not maintain a chain reaction.) So, in the case of a pebble-bed reactor, if you take away all the coolant, the reactor shuts itself down. The coolant (or more accurately the heat-transfer media, since it's used to move heat from the reactor core to the heat exchangers to make steam to turn generators) is integral to the design of the reactor.
To have a sustained reaction, there must be coolant present. If the coolant is present, then the reactor cannot melt down, because it's covered in coolant. If the coolant were to be allowed to boil off, then the reaction cannot be sustained and the reactor shuts off. So, Coolant=no meltdown, no coolant=no meltdown. Please find the way to make the reactor meltdown in the above scenario...
Give up? That's the difference between engineering and physical law. I can engineer a damn tough ship, but physical law says that if I add enough weight, it'll displace more weight than an equal volume of water, and it will sink. On the other hand, if I have a pebble and it releases X number of neutrons, nothing I can do will increase that number of neutrons or moderate them in such a way as to cause a chain-reaction, except adding a moderator, which, in-turn controls the chain-reaction. It's like claiming that I can make a light bulb that's hot get hotter and melt-down by turning off the switch.
Pebble-beds have been built and tested in the harshest ways, and no reaction can be sustained when the pebbles were "exposed" without the sustaining material. The only way to make a pebble-bed melt down is to take the pebbles, grind them down, extract the fissile material and make a regular nuclear reactor out of them.
And that's the whole point.
Life, the Universe, and Everything... in my image.
Just to clear up some misconceptions, the idea of pebble-bed reactors has been around since the 50's, however, due to the political environment other designs were promoted and used, as they do have higher energy potentials than pebblebed reactors do. Basically, for a nuclear reactor to "melt down", you have to have a configuration where enough nuclear material can be close enough together for the material to stay critical and generate enough heat where it will start to melt. The core idea of a pebble-bed reactor is that you encapsulate each piece of the fusion material with a protective coating that insures that even if it was let loose to react in an uncontrolled manner, the protective coating would keep the material from melting into a larger mass, which would then generate more heat even faster, etc. If you can keep the material from melting together, you can't have a complete meltdown. Materials technology has come far enough so that these protective pellets can be made safe enough that the pebblebed reactor can be created. Does this prevent people from breaking open the pebbles and inducing a failure? No. Does it prevent a bomb from exploding the reactor and releasing the material? No. Are there other ways to gain fusion material beyond attacking a commercial nuclear reactor? Yes. This is a risk vs. reward equation, we will need to get power someway, and simply dismissing nuclear as "too dangerous" is ignoring the fact that when we run out of oil, the world will be a much more dangerous place anyway as everybody fights for the limited resources. Why not AVOID the political mindset that in all likely lead to the US invading Iraq in the first place by using nuclear power?
Seriously, the breakdown of imports and been brought up a thousand times and shot down a thousand times. Until Arabs lose control of the liquidity of the market, they control oil prices.
The graphite is covered in silicon carbide, so it won't burn. In fact the Chinese pebble bed design IS relying on a passive system for control - the reaction can't sustain itself without the coolant present, and will quickly slow down and stop.
If you want to make a comparison with the Titanic, you should carry it all the way. This reactor is meltdown proof, the way the titanic would be unsinkable had it been placed in a desert. That is to say, it is possible it could sink beneath the sand and vanish, but there is not any scientific support for a theory as to how it could happen.
There is an excelent article on pebble bed reactors in wikipedia. Briefly, the idea is credited to a German physicist Rudolf Schulten. General Atomic is building one in Russia (link). Also there was a project at MIT under Andrew Kadak, but the website, gives an impression that the work did not go far.
> Please find the way to make the reactor melt down in the above scenario
Simple: Pebbles jam. It happened in Germany. If they're jammed, they can't expand properly.
Of course, the biggest risk for a pebble bed is not meltdown but a graphite fire.
Dear Lord: One of your creatures may be hurt tonight. Please let it be the other creature.
First off in a pebble bed design the graphite is encases in a ceramic, usually SiC. For a fire of the type you are describing all the ceramic coating of all the pebbles would have to fail. And I do not mean just a few small cracks but big chunks of it would have to fail.
Second the hydrogen production is not going to be from hot graphite in contact with water. The Hydrogen production will not be in any loop of the reactor but will be at the ends of power lines coming off the generator. This is not a safety factor with the reactor.
Third as far as lead-bismuth goes I only know of one production reactor that used that. The power plant for the Alpha class sub. Guess what it was a disaster. All of them have been withdrawn from service.
Should they still use a containment dome? I would say you bet. Seems like very cheap insurance to me. If nothing else it could help to protect if from terrorist attack or even milliatry action.
All of you points though are just not issues except for maybe the lead-bismuth breeder. I would have to do more research to see what the state of the art is with those.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
So in China when a reactor melts down, is that referred to as the 'American Syndrome'? M
The reason that the U.S. is not innovating in the area of energy production has to do with politics. America controls (directly and in the case of Saudi, indirectly) world oil production and therefore world energy. Alternate energy sources, especially those that free nations from the oil addiction reduce dependence on America and therefore reduce America's power.
China, knowing this, is actively persuing alternate energy policy including nuclear, hydrogen and more novel approaches. They want to detach themselves from the oil addiction so that they have independence from the U.S. and U.S. controled energy interests.
Again, politics.
But, the results are inevitable: As a result of these politics, the Chinese will inevitably control more advanced and more important energy technologies (both economicaly and ecologically). So the conclusion to this will be exactly the opposite of that desired by the status quo (America controlled energy). However, the administration doesn't care because they will be retired, rich, fat and happy (or dead of old age) when China turns it all around on America and effectively takes control of world energy production.
The reason that it can be true that 1+1 > 2 is that very peculiar nonzero value of the + operator
pebble bed reactors have a low density, so they don't overheat , even when all cooling breaks down. The Tchernobyl reactor did overheat. Then exploded. Then the air could reach the core and start a fire.
The low density approach is actually 50 years old. The first prototype was made in the fifties. The low density track was left behind by the more evolved high density approach. High density reactors got a headstart because compact reactors were needed in submarines. Freeman Dyson describes the history in one of his books.
The problem with nuclear power isn't the big scary scenarios that the mainstream anti-nuclear community put about. The problem is that economics suck, and probably always will. "Successful" national nuclear power programmes are propped up by artificial means--either direct government investment, or special-needs laws like the insurance liability cap, or both.
Sure, coal plants pump out a lot more garbage into the environment than nuclear plants, but coal plants have two big advantages: relatively small events don't wind up writing-off the whole plant; and you can take the damn things apart and fix them relatively cheaply because they aren't radioactive.
It isn't just "unreasonable regulatory burden" that makes nuclear plants expensive--it is the fact that the available energy density is extremely high, and any departure from equilibrium can result in sufficiently high energy density to result in plastic deformation of components of the core. Once that happens they're hellishly expensive to fix. Even relatively routine maintenance is extremely expensive due to the real safety requirements of doing engineering work in a radioactive environment.
"Inherently safe" design for fission reactors is an interesting area of research, and much progress has been made, but it isn't clear that any of them are really as safe as their designers would like to believe. And again, it isn't the possibility of catastrophic, world-ending melt-down that you need to prevent, but relatively minor excursions that will leave the containment intact but make a mess of the core.
Older designs, such as the CANDU (which has a negative temperature coefficient of reactivity, if memory serves, meaning a temperture spike will damp the reaction down) are already more-or-less "melt-down-proof". But they have also proven to be bloody expensive to maintain--far moreso than coal-fired plants run by the same utility.
These are all reasons I got out of the nuclear engineering business many years ago--the core physics of fission power is such that it is very hard to create reactors that are going to be economic to operate over the lifecycle of the plant.
--Tom
Blasphemy is a human right. Blasphemophobia kills.
Read the article, this reactor design (the CANDU) does not rely on pebble expansion for reaction moderation. The coolant itself (heavy water) provides the moderator that makes the reaction possible. Without the heavy water, there's no reaction. The generator also runs in the 900 degree F range, which is not hot enough to flash-ignite graphite. The Chernobyl reactor didn't ignite the graphite until the core reached 2200 degrees farenheit. The pebble-bed without coolant would probably back down to only a few degrees over ambient temperature without the moderating heavy water. The reactor efficiency is so low (195MW vs 2GW for a typical U.S. reactor) exactly because the pebble-bed never gets to insanely high temperatures.
So, the only time it's hot is when it's covered in water. Difficult for the graphite to ignite without an oxygen source. When it's exposed to air, the pebbles are already cooling to near ambient temperatures and can't get to the several thousands degrees it takes to ignite graphite.
Even a graphite fire is not dangerous if contained in a containment vessel. Chernobyl was only a disaster because the Russians used a single-wall design for their containment vessels, and the initial steam explosion blew that off the building. Then the core was exposed to open air. All U.S. reactors are double-walled and would have contained a Chernobyl type meltdown.
Read the article and research the design. Meltdown is prevented in this design by physical law, not by thermal expansion. (Okay, that's a physical law, but it's not the one we're depending on.)
Life, the Universe, and Everything... in my image.
The current crop of CANDUs are unreliable and expensive to maintain. Ask any Ontarian paying a whack of "stranded debt retirement" on their hydro bill, and they wouldn't wish CANDU on anyone.
When people talk about breeder reactors as "producing more fuel than they burn", what they mean is that the reactor is run on either U-235 or Pu-239. It produces heat energy which is converted into electricity.
At the same time, excess neutrons from the reaction are reacted with an otherwise inert blanket of U-238 around the reactor, converting the U-238 into Pu-239 which can then be used to run the same reactor, or other reactors. It turns out that Pu-239 production is faster than Pu-239 or U-235 consumption.
It is relatively easy to use chemical methods to separate the produced Pu-239 from the leftover U-238 in the blanket, certainly MUCH easier than separating U-235 from natural uranium.
So it's not a perpetual motion machine because a resource is used up, i.e. the natural U-238, but that resource is plentiful and the overall process is easier than the conventional method of getting fissile fuel.
The reason that breeder reactors aren't widely used is partly technical, because they're fairly complex things to design and operate, but mostly political because the Pu-239 produced can relatively easily be used in bombs.
"Studies have shown that people who eat peanuts live longer than those who do not eat."
Americans, 5% of global population, produce over 30% of the output on 20% of the energy. We're very productive, and very efficient, compared with most of the rest of the world - vastly more efficient than any comparably sized group in either of those three measures. Of course, we're too wasteful, too - our economy hides the cost of our energy consumption. When we reduce our energy consumption, our economy will benefit, and lead the rest of the world to a more sustainable production system. But trashtalking our relative efficiency isn't the way to lead us there.
--
make install -not war
You think just the same way that Timothy McVeigh used to on Usenet. I thought he was a dangerous nut before he murdered close to 300 people in his attempt to do exactly what you suggest. Try a google search and look for his posts on Usenet.
Bin Laden and McVeigh are both cut from the same cloth. The most powerful tool you have for changing your government is the Web.
Bin Laden has changed nothing, achieved nothing. The IRA achieved nothing. Mao and Stalin ultimately achieved nothing.
Ghandi won India's freedom without a shot being fired. Lech Walensa in Poland, the Velvet, Rose revolutions, far more is achieved with the power of speech than has ever been achieved with guns.
The East Germans I met in the 1980s never asked for guns, they wanted photocopiers and type writers. They knew what they needed.
Looking for an Information Security student project suggestion?
Try http://dotcrimeManifesto.com/
> encases in a ceramic, usually SiC
Above 1250C, SiC degrades relatively easily in a reactor environment;. it has varying degrees of instability above 900C, and remember that PBMRs are definintely not low-corrosion environments. A coolant-devoid reaction in a pebble bed maxes out typically around 1600C (sometimes lower); too low for meltdown but not too low to seriously jeapordize the graphite.
> The hydrogen production will not be in any loop of the reactor but will
> be at the ends of the power lines coming off the generator
Incorrect. The reason pebble beds are desirable for hydrogen production is direct thermolysis of water in the presence of a catalyst; pebble beds can reach sufficient temperatures, unlike conventional PWRs, to do this.
> as far as lead bismuth goes I only know of one..
I don't care if you don't know about a subject. Lead or lead-bismuth reactors have been built for experimentation and/or studied in France, Japan, the US, Italy, Russia (extensive), and other countries. Lead-bismuth has gotten a lot of attention recently in the nuclear power industry.
BREST is little like an Alpha-class sub's reactor. One of the most prominant features of BREST is that it is largely convection cooled. Secondly, thanks to data from Alpha, lead compatability issues have largely been addressed. The main corrosion issues were with steel; despite having largely resolved this through oxygenation and chromium steels (yes - a coating of rust, and/or stainless steel - the first Alpha reactors didn't even use stainless steel for many corroded parts!), the lead tank on BREST is mostly concrete (which never had compatability issues). And if you want to talk about corrosion, you don't have much to point to from US reactors - look at CANDU's recent troubles with feeder pipes, for example. Even if throuh some miracle the concrete base were destroyed, the lead would just solidify and trap its contents within.
Dear Lord: One of your creatures may be hurt tonight. Please let it be the other creature.
The "too cheap to meter" comment is addressed later in the comments, and was from one guy talking to a group of science-fiction writers in the 1950's. But yes, a real nuclear scientist said it, so I'll give you that.
On the other hand, in the U.S. Nuclear Reactors have killed how many civilians? So far as I know, the number of civilians killed in nuclear accidents at power plants is... zero. Yes, there have been deaths of workers, yes, you could argue that a few plants have leaked radiation here and there, but when you consider that the CDC is claiming 30,000 deaths a year from coal plants in the U.S., it makes for a hell of a weak argument.
Besides, the "safe" claim isn't even being made by the U.S. government, it's coming from China. As for me, I think nuclear is a great idea, and I'd rather be living 10 miles from Yucca Mountain than the 10 miles I currently live away from a coal plant that's rated one of the cleanest in America.
As for your "dirty bomb" statement, yeah, give it a try. Start by walking into a nuclear power plant, past the six layers of security. Then enter the core, ignoring the fatal dose of radiation you'll be bathed in. Grab hold of a few dozen pebbles, ignoring the heat that burns the flesh off your hands and arms. Take them home. Grind them up, again, ignore the fact that the fumes of the uranium or plutonium are among the most powerful and fastest acting poisons known to man. Use fluorine (a controlled substance also instantly fatal if breathed) to create UF6 to separate the Uranium from the graphite gas. Then use a million dollars of platinum to catylize the UF6 back to uranium metal. Stick it to 100 pounds of C4 and detonate it in downtown New York. Of course, the fact that you'll set off every airborne neutron detector that homeland security and the air force (and a half-dozen spy satellites) have before you leave your house might slow you down. Not to mention the continous man-hunt looking to find you.
You may not trust the government with this stuff, but consider the alternative. If there's one thing I'm not worried about in this country, it's how well our fissile material stockpile is guarded. When you realize that it takes three semis, twenty secret-service agents, the FBI and the army to move 20 grams of *spent* material to be used as the thermal warmers for the Pathfinder rover, you realize that the government is very serious about the security of this material.
story from "Managing Martians" by Donna Shirley
Life, the Universe, and Everything... in my image.
Why don't *you* RTFA? They're not building a CANDU, they're building a PBMR. Furthermore, pebble beds run in the 900C range, not 900F. Their "loss of coolent" scenario is as high as 1600C - plenty to burn graphite. I can skip all of your comments about "covered in water", because CANDU uses water as a moderator, not pebble beds (strange that you would think that CANDU uses graphite, however...)
Dear Lord: One of your creatures may be hurt tonight. Please let it be the other creature.
Until we get either lots of electric or partially-electric vehicles or nuclear hydrogen, nuclear is going to be used to light lights and run motors; it will compete primarily with coal and natural gas. Gas-fired turbines are cheap to build and easy to site. Coal plants burn cheaper fuel but are harder to site and take longer, and the utilities stayed away from nuclear after the WPPSS bond default (stemming from cost overruns on two nuclear plants and consequent bankruptcy). The people who run utilities have a different mindset from dot-commers; they like their jobs, and they won't keep them if things stay even moderately exciting outside of things like hurricanes and ice storms. Surprises like having your multi-billion dollar plant go from 75% complete to 35% complete as a consequence of one NRC-mandated redesign, during a period of 20% interest rates (Carter administration - look it up) are things they can quite do without. The technological, financial and political risks of nuclear are much higher than fossil-fired, and are compounded by the duration of construction.
THAT's why nobody has build a new nuclear plant in the USA for the past 25 years. With luck, maybe things will change.
Sustainability and energy independence essay
Then China has changed its plans since the last time this article was up here (last September) because I spent hours researching it then and was quite impressed with their reactor design. Several other people have commented on this topic that they are building a CANDU variant, with graphite coated pebbles of slightly enriched uranium bathed in a heavy water moderator.
If they have moved away from that design, then they are in danger of burning the graphite shells and a dozen other problems (Uranium can react spontaneously with air after all.)
Lo and behold, the second sidebar article says they are going for an HTGR design using the packed pebble design. So much for their "innovative new design" that they screamed all over back in September.
Of course it would still be hard to ignite the graphite in a helium atmosphere, but that also assumes a containment vessel is present, something that China, along with Russia, seems to think is a luxury.
Of course, the second sidebar also points out that they have already done "absolute failure" scenarios where they've turned off all the safety systems and watched the reactor shut down.
Life, the Universe, and Everything... in my image.
This is a minor point, but South Africa's involvement is not at all surprising. South Africa has some pretty high technology, due to its unique position as one of the only stable democracies on the continent, and being involved in various regional conflicts. They were the continent's only nuclear power until they voluntarily gave it up, they build some of their own military aircraft, and so being handy with reactor technology is not too surprising.
Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
Why don't *you* RTFA? They're not building a CANDU, they're building a PBMR. Furthermore, pebble beds run in the 900C range, not 900F. Their "loss of coolent" scenario is as high as 1600C - plenty to burn graphite. I can skip all of your comments about "covered in water", because CANDU uses water as a moderator, not pebble beds (strange that you would think that CANDU uses graphite, however...)
AFAIK they are building THTR-Type Devices. That are Pebble Bed Reactors which are cooled by Helium.
This type of device is inherently safe from meltdown because
which is absolutely inert
The german THTR-300 at Hamm-Uentrop has been a demonstration reactor at commercial size (300 MW). It was shutdown after proving to work well.
The reason to cancel the further development and building was completely political because there is no chance to get public acceptance for any Nuclear Powerplants all over Germany after Tchernobyl and Three Mile Island.
The reactors themselves may be safe, but the problems of the required fuel production and handling, especially the waste disposal, are nowhere in the world sufficiently solved. Thats a truth whatever the Nuclear Industry and there political gofers may say.
CU
And having many small nuclear power plants is much more safer than having one megasized nuclear power plant to power an entire city. Why? Simple, compare what happens if one huge plant fails than if one small plant fails.
And IIRC, the material to be heated with the reactor is not water, but helium.
From the sept. wired article:
I think that everything argument against these new nuclear plants is the existing FUD caused (with all reasons) by traditional nuclear plants.
"Success" is defined subjectively. Is it the nation with the most land? Resources? Quality of life? All of the above?
Hitler turned Germany from a destitute war-torn nation into an world economic power house in ~10 years. That's "success" in a lot of people's eyes. And why what happened afterwards is even more of an abomination.
From the ORNL:
I first heard this fact from a professor of mine, and it made sense at the time as coal is ultimately a source for uranium as well as radium. (That's where the Curies got their uranium from, after all.) This is the first time I did a web-search to verify his statement, and I wasn't surprised to see that it agrees with other people's calculations (Google for "coal radiation").
Ben Hocking
Need a professional organizer?
I do not know where to put this so I'll attach it to this post. Germany has experimented extensively with breeder-type reactors but we sunk nearly 7 bilion german marks (3.5 billion Euro) into those projects without going anywhere.
The concept of pebble-bed reactors was developed in the 1950s by a german scientist named Rudolf Schulten. The first prototype had been in use between 1966 and 1988 when the project was discontinued after the chernobyl incident. The protoype used helium as a coolant but other inert substances like nitrogen or carbon dioxide are also possible maybe even water but all sources I could find claim that these designs used inert gases as coolant and moderator. Pebble-bed reactors use either uranium, thorium or plutonium for the reaction and produce new fissionable material during the reaction.
There were also plans to build a commercial type reactor using this design but the reactor was never finished due to technical difficulties with the handling of the pebbles themselves and because of safety concerns following the destruction of the chernobyl plant.
There was also another type of breeder which used uranium as fuel and natrium as coolant but there were so many technical difficulties and safety concerns (mainly with the handling of the hot liquid natrium (300 C) that the reactor was never used at all.
Research into breeder technology was cancelled after 1986 mainly because of the chernobyl incident. The other main concern was that breeder type reactors produce fissionable materials. If you use uranium as fuel you will get plutonium as product. So some were concerened that this material might be used to build bombs. This was especially a concern with the natrium-cooled reactor since it didn't use fuel enclosed in pebbles like the other reactors did.
Jeff
"I'd much rather see them go with a lead-bismuth breeder. It's a breeder (so you can utilize more fuel), it produces less waste, the waste is easier to handle, it's anti-proliferation, there's no graphite, there's no pellets to jam, etc."
That's the trouble with you nuclear physicists, you make out you know what you're talking about and then round the whole lot off with 'etc', as if everyone is going to fill in the gaps.
What does 'etc' signify? Certain death? Mild itching? What?! For God's sake man! Tell us!!
1) The reaction rate isn't the problem; latent heat in the graphite if the core is exposed to air is the problem.
:)
2) The "safety" mode of cooling is air cooling - i.e., if the reactor is ruptured, air can come in and cool it. In such an event, though, the graphite can burn.
3) The pressire is quite high in PBMRs; one that I read about was 69 bars for the core (a bar is roughly 1 atm). If it's not high, it won't run a turbine very well, now will it?
4) The German reactor was shut down due to a variety of reasons, but when it was shut down it had just gotten over a problem with a pebble jamming the retrieval system and causing big complications, including a minor radiation release and a shutdown that would be unacceptable for a commercial plant.
Dear Lord: One of your creatures may be hurt tonight. Please let it be the other creature.
As I mentioned previously, meltdown is not the serious risk; it's only a risk if pebbles get jammed. The serious risk is fire from a rupture, and especially the intake of water due to a hydrogen-generation explosion for hydrogen-producing reactors.
So, if you want to claim that it has been "tested" against failure, point to where they:
* Jammed the pebbles and then shut it down
* Ruptured the containment vessel while it was operating
* Detonated hydrogen gas in the hydrogen production loop to see if any water posed a threat to the core.
> the material to be heated with the reactor is not water, but helium
Sigh, how many times do I have to go over this? Apart from a significant containment failure when it is raining (no containment structure for chinese PBMRs), water is a secondary loop for hydrogen-generating reactors. They don't make the hydrogen through electrolysis; they run the helium (via as short of a distance as possible so as to not lose much heat) up to a tank of water and a catalyst (for example graphite), which creates hydrogen through thermal decomposition of the water. A rupture of the helium lines risks getting water vapor or outright water into them, in addition to other potentially serious problems involving the hydrogen itself.
Dear Lord: One of your creatures may be hurt tonight. Please let it be the other creature.
Liquid metal is hard stuff to contain for long periods of time - it works it's way into cracks and attacks the metal at the crack tip.
So it looks like you are describing the wrong mechanism and the wrong material - so why should your assertions based on this be correct?
Face it - these are not a mature technologies. Pebble bed at least is furthur along, and is going into production for the first time after a series of prototypes.
As for your "dirty bomb" statement, yeah, give it a try. Start by walking into a nuclear power plant, past the six layers of security. Then enter the core, ignoring the fatal dose of radiation you'll be bathed in. Grab hold of a few dozen pebbles, ignoring the heat that burns the flesh off your hands and arms. Take them home. Grind them up, again, ignore the fact that the fumes of the uranium or plutonium are among the most powerful and fastest acting poisons known to man. Use fluorine (a controlled substance also instantly fatal if breathed) to create UF6 to separate the Uranium from the graphite gas...... blah blah blah...
Yeah, way to go cowboy - tell everyone how to do it!
(Note to moderators: the above comment is meant in jest. Okay? Good!)
> the generative capacity of the uncooled spheres is not adequate to
> exceed the cooling capacity of the old itself
That is not true. The generative capacity of spheres when hot being reduced to where the reaction rate won't increase further is dependant on the *EXPANSION* of the spheres. Objects cannot expand when they get jammed.
> will not set off any sort of significant reaction
Hot graphite + water = H2 (likely exploding because of the temperature)
Hot graphite + air = fire (not guaranteed, but a solid possibility)
> I personally witness the shutdown test
Which, as I mentioned, doesn't cover any of the *Real* safety risks. That's like me demonstrating the safety of gunpowder by disolving it in water and saying, "look, I can make it as wet as I want without it exploding!"
> (snipped out personal attack)
When you address how you expect jammed pebbles to expand to reduce the reaction rate, or why a ruptured core wouldn't be a risk for a graphite fire, let me know. Until then, go bother someone else.
Dear Lord: One of your creatures may be hurt tonight. Please let it be the other creature.
According to the oft quoted ORNL report, there is 0.00427 millicuries/ton of coal, and each ton releases 6150 kilowatt-hours(kWh)/ton. This is therefore 6.9431e-7 mCi/kWh. The DOE's Energy Information Agency gives the world total of energy production for 2002 as 4.0512e17 BTU or 1.18699e14 kWh. Since only 9.756e16 BTU or 24.08% of the world energy production is coal for 2002, we can come to a total of 19.85 MCi/yr. Some estimates for Chernobyl put the radiation released at 1.2e19 Bq or 320 MCi. It would take coal plants at the 2002 rate of production 16 years to equal the release from Chernobyl. On the 26th of April, it will be the 19th anniversary of the Chernobyl accident! Is it really that intelligent to put the noose around the neck of our nuclear industry because a near bankrupt Cold War enemy with a poorly designed reactor had an accident that almost certainly could not happen with US reactors?
Suddenly, the hairy finger of a familiar monkey tapped me on the shoulder. It was time.--G. T.
"Above 1250C, SiC degrades relatively easily in a reactor environment;. it has varying degrees of instability above 900C, and remember that PBMRs are definintely not low-corrosion environments. A coolant-devoid reaction in a pebble bed maxes out typically around 1600C (sometimes lower); too low for meltdown but not too low to seriously jeapordize the graphite."
Notice you said degrades not disintegrates. The idea is that you never let it get to 1600c. Combine it with He as the coolant the chance of a graphite fire is extremely, extremely, low.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
On the other hand, in the U.S. Nuclear Reactors have killed how many civilians? So far as I know, the number of civilians killed in nuclear accidents at power plants is... zero.
Define U.S. Nuclear Reactors. I'd define that as any reactor operated by the USA. Reasonable? In that case, there indeed have been deaths and rather horrible accidents.
The 1961 SL-1 BWR experimental reactor accident in Utah comes to mind. Three fatalities, one was by control rod impalement and/or irradiation, the other two were from irradiation.
Some info about it here: http://www.radiationworks.com/sl1reactor.htm
The History channel has a documentary on this accident. Truly gruesome.
Sig for hire.
Intersting that for all your knowledge of the pressure of a PBMR, you assume (completely incorrectly) that the primary coolant loop is used to turn the generators. There is no reactor design that I know of where this is true. The primary loop carries radiation, and the idea of pumping radioactive material through a turbine from high to low pressure (because that's how turbines work after all) would mean all of the equipment in the generator house would quickly become radioactive. Not very conducive to generator maintenence.
On the other hand, in the real world, the heated primary loop runs to a heat exchanger where it heats the secondary loop, usually water from a river or lake, that is flashed to steam, run through the turbine and then used to pre-heat the incoming water in those big concrete cooling towers that everyone associates with nuclear reactors (even though most coal and gas fired plants have them as well.) The water is then either recycled (rare) or returned to the water source (river or lake) at slightly elevated temperatures. This means that the secondary loop is only "exposed" to a minor dose of radiation (through radiation leakage through the heat exchanger) before it is dumped. The overall radiation level is usually barely higher than background on release of the secondary coolant.
Thus, the primary coolant (in this case Helium) is locked in a closed cycle at a fixed pressure and exchanges heat to the secondary coolant loop. It never sees a turbine and is probably driven by high-speed impeller pumps in a closed loop. No turbines. The gas is kept at high pressure because helium is such a rotten carrier of heat. Liquid sodium is much better, but poses all kinds of other problems. The U.S. uses a lot of water steam, but high-temp steam is extremely corrosive.
Again, surprising that you would think that the primary loop is used for turning the turbines.
Life, the Universe, and Everything... in my image.