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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...
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
Actually, the design of these reactors is nothing short of ingenious.
The reactive elements are spherical pebbles, each with just a tiny amount of radioactive material inside.
Individually, they do not have enough material to go critical.
when you put them all together inside the reactor, the shape of them puts its nearest neighbour just in range to react.
If the reaction begins to cascade, the elements heat up and expand. This automatically seperates them and cools the stack back down.
You can pour new elements into the top, and extract the lowest from the bottom in a relatively safe manner.
liqbase
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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!
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.
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
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
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.