Joe Perez

iTrader: (8)

Or at least, it can be safer.

The Chinese are tinkering with a rather ingenious design for a subcritical Thorium-fueled reactor. There are a number of interesting advantages over present light-water designs (such as the BWRs and PWRs that make up 100% of the US commercial reactor inventory, and the vast majority of European and Asian reactors as well.)


For starters, Thorium, as a nuclear fuel, is incapable of sustaining a chain reaction on its own. It just isn't sufficiently reactive. In order to get it to do anything, you have to shoot a continuous stream of protons at it from a particle accelerator. Reactor power is adjusted by increasing or decreasing the intensity of the proton beam, so there are no control rods (fewer moving parts). And since the reaction stops instantaneously when the beam goes away, an electrical blackout inherently means an immediate and total shutdown.


The reactor is graphite-moderated, which is usually a dangerous thing (it's the reason the Chernobyl reactor had a positive void coefficient, which is what caused it to explode) but the fact that the fuel itself is a liquid at normal operating conditions allows a very unique passive safety feature. Each fuel tube has a plug at the bottom which melts if temperature in the core exceeds an upper limit. When the plug melts, the fuel simply drains out into a pit. So even if the system goes totally apeshit, the core essentially disassembles itself for you in an orderly fashion.


Since reactivity is externally controlled, the fuel can be run for longer, achieving more thorough "burnup", with the result that less waste is produced. And the waste products have much shorter lifetimes than those of an enriched uranium reactor- hundreds of years rather than thousands.


Thorium is much more abundant than uranium. And like the CANDU reactor design, this one can also run on "blended" fuel. Translation: it can actually be fueled in part with nuclear waste from other sources, such as spent fuel from light-water reactors, dismantled atomic bombs, etc.


Since there's no water involved, the reactor operates at atmospheric pressure. So there's no possibility of coolant boiling, steam explosions, hydrogen explosions, etc.


The US experimented with this technology back in the 50s, but abandoned the work when it became clear that reactors of this type were not capable of breeding fuel for use in nuclear weapons, something which was considered desirable at the time. Hmm. An inherently proliferation-proof design.

y8s

iTrader: (8)

i take it you need another power source to power a proton beam? maybe just a small generator to kickstart the process

jtothawhat

iTrader: (7)

I thought we all where supposed to buy IODINE tablets?

gearhead_318

iTrader: (1)

I don't know much about nuclear energy, (power plants or weapons) but it seems like a bad idea to have a nuclear power plant that produces weapons grade plutonium or uranium on the side. Could a nuclear power plant explode through fusion or fission like a nuclear weapon does, or does a "compromised" plant "just" leak radioactive stuff? Can somebody please tell me what I'm supposed to be afraid of?

jtothawhat

iTrader: (7)

Nothing is wrong with nuclear energy, in 50+ years we have been using it there has been 3 significant problems. 442 Nuclear power plants exist creating power for millions of homes and businesses world-wide--also, they power a lot of our Navy with reusable energy only requiring refueling every 20 years or so.

I don't think it's anything to be scared or worried about, you have a much higher chance of getting killed by a million other things in this World, including being ran over by your Miata while you're working under it.

Nuclear plants also cannot 'explode' like a nuclear weapon either, as far as I know. Problems happen when the rods are exposed and melt therefor releasing radioactive material.

JohnX

iTrader: (1)

The dark? Without nuc power we live in darkness.

falcon

iTrader: (13)

Nuke plants don't explode like a bomb. Too many people think nuke plant = nuke bomb. Morons.

Have fun ODing on your KI pills and having health issues because you took too much and are so stupid that you started taking it before any actual meltdown, and you can't take it for longer than 7 days. Which means if anything DID happen, you're fucked anyways. <--- directed at morons who believe Faux News, not anyone here specifically





Leave it to the Chinese to fix everything. They are going to take over the world... hell don't they basically own the USA anyways? So what, when they call the trillion $ loan and you guys don't have any money does that mean we are now "New China's Top Hat?" Lolz

chicksdigmiatas

iTrader: (11)

Not really, I will let Joe handle it explaining it to you. I think this is a great idea and I read and did a little research, and the thorium reactors are a great idea that needs to be developed here, but we all know, tree huggers say nuclear power is the devil.

Joe Perez

iTrader: (8)

Well, you have to remember that at the dawn of the nuclear power era, WWII was a recent event and the US was very much in the throes of the cold war. At that time, we "needed" as much weapons-grade fissionable material as possible, so in considering the design of any reactor, it was considered beneficial if it was able to produce Pu-239 or U-233 as a byproduct of normal operation. Some reactors (so-called breeder reactors) are specifically optimized for this purpose, and they actually generate more fissile material than they consume.

In modern times, of course, the tables have turned. We (the US) now have enough nuclear bombs to last quite a while, so the concept of further proliferation is deemed a "bad thing", and the goal is now to figure out how to generate power without also enabling new weapons to be constructed.

The Canadian CANDU reactor is one ideal candidate under these criteria (India copied this design after the world reacted negatively to their detonating a bomb). It is able to run on completely unprocessed natural uranium, so in theory, a country could install and operate CANDU-style reactors without also having to build an enrichment infrastructure which would also be capable of creating cores for nuclear weapons. This was one of the big sticking points in the recent controversy surrounding the Iranian nuclear program (which culminated in one of the coolest computer viruses ever written by man.) Iran claimed that their enrichment program was for energy-generation purposes, but the same machines can be used to create weapons-grade nuclear material. Alas, CANDU is not without its drawbacks- they are physically enormous and expensive to construct, and requite heavy water to operate, adding further to their expense.



No.

To generate an actual nuclear explosion is quite difficult. Familiar with the Manhattan Project? It took the world's most brilliant physicists four years to figure out how to produce a nuclear weapon, and that was after they had some hands-on experience with operational nuclear reactors. In addition to refining the nuclear material to a level of purity many times greater than that found in a nuclear reactor, the physical geometry of the device is critical. You have to get just the right amount of material arranged in just the right shape and then compress it in just the right way, or else it simply fizzles.

There has never, absolutely never, been an accidental thermonuclear explosion on any scale whatsoever. Short of mis-handling a core which has been specifically designed for the purpose of being a bomb, the laws of physics just won't allow it to happen.

You **** up a nuclear reactor badly enough and it'll melt down, leak, and if you're having a really bad day, undergo a steam explosion. But expecting a nuclear explosion from one just isn't reality.


The only thing we have to fear is fear itself.

And spiders.

gearhead_318

iTrader: (1)

I'm in favor of nuclear power. I didn't/don't think a NPP can explode like a bomb, but I figured as long as I had the opertunaty, I might as well ask incase I happend to be misinformed.
I was making fun of the panicky people who believe things like Japanese cars are going to be radioactive when I asked what we're supposed to be afrade of.

Is there some big Chinese dude who's gonna break all our legs when they want their money and we don't pay up?

falcon

iTrader: (13)

Lol... Yao Ming?

Joe Perez

iTrader: (8)

Yes, with a but.

Remember that the power grid works both ways. You can pump power into it, and you can also pull power from it.

All nuclear power plants have sufficient on-site capacity in the form of diesel generators to run the plant in the absence of a connection to the grid. (This was the system that was destroyed by the Tsunami at Fuku and put them into this whole mess.) So in theory, any existing nuclear plant would be capable of a so-called "black start", that is, starting up the plant from scratch without any external power.

In practice, however, this would never be done.

A supply of offsite power is considered a prerequisite for safe plant operation. In fact, during normal operation, the plant itself is actually powered by the grid, rather than by its own turbine. The plants are designed such that a loss of offsite power causes an automatic shutdown. It's intended to be a safety feature. The idea is that if offsite power was to be lost and the backup systems were offline, you'd lose control of the reactor. Ironically, this very design feature is what killed Fuku. When the quake hit and the grid went down, the reactors automatically tripped, shutting down the turbines. The batteries and diesels functioned normally until the wave hit, and when that happened, all power was lost. In theory, if the plant had been designed such that a loss of offsite power kicked the reactors down to a low power level but left the turbines and main generators running, then we wouldn't be having this conversation.

(A similar idea, and one which I've never heard mentioned but expect somebody to propose sooner or later, would be to install a small auxiliary turbine and generator, possibly inside containment on the primary loop, which would be capable of generating enough power to run the plant systems even after a trip, by functioning on decay heat alone. In the unlikely event that this is actually an original idea on my part, I hereby grant permission for anyone to implement it provided that you pay me 0.01 % of any proceeds generated by it.)

But that's all just speculation. This system has always worked reliably in the US. There have been hundreds of blackouts since we first started generating nuclear power, and every nuke plant has always tripped, switched to backup, and performed a safe shutdown.


So to get back to the question- yes, you could in theory use the backup diesels (presupposing that they were large enough) to fire up the accelerator and "kickstart" the reactor from a cold shutdown. In actual practice, it is hugely unlikely that this would be done. Since normal operating procedure is to use grid power to start up the plant, it would make no sense to connect the accelerator to the backup generators in the first place, as it would be the first thing that you'd shut down in the event of a loss of offsite power.

Joe Perez

iTrader: (8)

And this is one thing that really kills me about all of the anti-nuke proponents. With nuclear power, there is a finite, non-zero probability that something might go wrong, so we'd better not do it.

If I get up tomorrow, get in my car, and drive to work, there's a possibility that I'll be hit by a truck and killed.

Better ride the bus instead. Except, what if someone sitting next to me on the bus has smallpox and they cough on me? I could die.

Well, I guess I should ride my bicycle instead. Except that there's a steep hill, and there's a possibility that I'll have a heart attack and die while going up it.

Ok, I'll walk. But wait- I might get a blister on my heel, which could become infected, lead to gangrene, and kill me.

Guess I'd better not go to work at all. Except if I do that, they'll stop paying me. After a decade or two of unemployment I would be flat broke and homeless, and I'd freeze or starve to death.

So there is absolutely nothing at all I can do which is "safe."



Same deal here.

No nukes. But also no oil drilling (kills ducks), no oil importation (funds terrorists / depletes economy), no coal (kills lots of coal miners), no hydro (dams kill fish and alter the local ecology), etc. Wind power would be great if the whole US were under a constant category 1 hurricane all the time. Solar would be great if it were always daytime (and if we had the capacity to cover an area four times larger than the surface of all of the land masses on earth with solar panels).

So basically we need to generate less electricity, but at the same time, we all need to buy electric / plugin hybrid cars. How did you say we were going to charge them?

I've got no problem with pouring money into hippy green-energy BS. It keeps the liberals happy and makes us look good to the electorate. We just need to understand that at best it's capable of supplying only a small fraction of our (the world's) current energy demand, to say nothing for the demand 10 or 20 years from now, when everybody in China and India moves into an apartment in the city with air conditioning and an electric stove.

Nukes are the answer.

NA6C-Guy

iTrader: (1)

Yes, nukes are the answer. The ONLY answer we currently have.

I get so pissed when I see someone on one of the news networks talking about how nuclear is bad and we need to push to have it banned. Clearly these fucktards don't understand the role nuclear plays.

Earlier I saw some idiot on Fox News spouting off some bullshit about Chernobyl causing something like 250k deaths because of cancer and some other ****. That is ******* ridiculous. **** like that scares the less educated population into agreeing with retarded plans like this.

Also, wouldn't Fukushima have been alright if the generators weren't destroyed? Surely they could be build more safe from elements/disasters in the future. Enclosed in their own water tight buildings or something.

y8s

iTrader: (8)

Go walk around chernobyl's site for a few days without protection.

that's the problem with nuclear disasters. it's a lasting damage. if a gas plant or coal plant fails destructively, **** just burns down and is gone. You wont get sick or die investigating it a couple days later.

of course one could argue that coal is probably WORSE than a nuclear disaster since the health problems associated with burning it are pretty damn lasting. there is a reason reputable news sources put the term "clean coal" in quotes.

Braineack

iTrader: (62)

also the world is safe:

JasonC SBB

Here's another great chart
http://xkcd.com/radiation/

kaisersoze

iTrader: (8)

It's interesting that that nuclear development is essentially held hostage to fear and money.
There have been several different versions of nuclear plants that are much safer than the older conventional light water reactors but we continue to use the more dangerous older plants because it is too expensive to build newer reactors.
For example the high pressure pebble bed reactor concept where the fuel is encase in ***** of graphite and helium is used as a coolant removes much of the complexity of light water reactors and cuts radioactivity dramatically as well. But of course the Germans shut the only active ones down after chernobyl because politicians passed a no nuclear power law. Again instead of improving the design we keep using old stuff.

Braineack

iTrader: (62)

old stuff has better lobbyist.

chicksdigmiatas

iTrader: (11)

People fail to mention that coal plants also produce radioactive elements. Maybe once China develops the thorium reactor, we can sell all of the thorium our coal plants produce to them.