Buick and Deere, I have questions?

Gun guru · Mar 16, 2011

With all the talk below about reactors and you work in one or you used to work in one, I have questions.

1. Are all nuclear power plants pretty much the same, IE: A chain reaction is needed to produce heat that turns water into steam and then the steam turns turbines. (I am assuming what I said is true). (fission reactor)

But....In France they are working on a Nuclear fusion reactor (is this true) And a large group of nations are building this.
What is the advantage of a fusion reactor over a fission reactor? Is a fusion reactor self sustaining or something?

And how does the chain reaction work in any nuclear plant? And how is the chain reaction controlled so that it doesnt meltdown? (I assume water is used extensively)
It just seems that being able to have a ball of uranium go critical would be hard to control.

sotxbill · Mar 16, 2011

dont they use the carbon rods to slide down between the fuel rods to asorbe and slow down the reaction.. and then pull them back up a bit to turn up reaction.

sotxbill · Mar 16, 2011

oh and I did sleep at a holiday express last year...

thats all I know about the nuclear plants and I saw that on a childrens show. sorry... Bill

Anonymous-0 · Mar 16, 2011

BuickandDeere can tell more about particular reactor types used today. Fission is breaking apart a molecule and fusion is combining two molecules (hydrogen). Both give off energy with fusion providing much more and also is cleaner, less dirty byproducts. Fission is a atom bomb and fusion is a hydrogen bomb. To date it roughly takes a small atom bomb to start the fusion process and then no way to control it. Past ideas have included massive magnetic force fields around a fusion reaction but only theory. Recent idea is to use extremely powerful lasers to provide the massive starting energy and to ultimately control the "explosion". All reactors today the fission because it is the only one that todate can be controlled.

big fred · Mar 16, 2011

Several places working on fusion, each place has a different way of approaching it. Once there is a breakthru, it will probably be another 25-50 years until the materials science catches up to make a practical powerplant. Very much worth the effort and expense to do the research, though. The payoff, if they can get there, is huge.

ErnieD · Mar 16, 2011

http://www.lle.rochester.edu/

CH(upstate,NY) · Mar 16, 2011

Change the word molecule to atom.

old · Mar 16, 2011

There is the fusion and the fision type of reaction. One we can control the other is what are sun is and if we some how start that on here on earth we is all gone because it will feed on any thing unless what I was taught in the Navy is wrong. Yes the system we use to produce power is used to heat water into steam and then in turn turn a turbine or turbines to product power. There are control rod that if in or close stop the reaction and if pulled out starts the reaction. My Brother could fill in the blanks better then I can because he did that for a living for about 35 years both in the Navy on subs and in civilian plants

TomH in PA · Mar 16, 2011

The reactors in Japan are a very old, obsolete design. Better than what the Russians had in Chernobyl, but more like Three Mile Island than one that would be built today. New designs wouldn't have those problems cooling down after a power failure.
Reactor Design Discussion

Gun guru · Mar 16, 2011

thanks, that is the info that I wanted to know.

It sounds like too much hype and hysteria over the reactor(s) and not enough worry over the main problem, the tsunami wiping out thousands or people.

TomH in PA · Mar 16, 2011

"other is what are sun is and if we some how start that on here on earth we is all gone because it will feed on any thing unless what I was taught in the Navy is wrong"

Naa. Fusion is what makes the H-Bomb so powerful, but it takes a tremendous amount of heat and pressure to keep the reaction going. Lots of them were touched off in the 50's by the US and USSR.
H Bomb

MarkB_MI · Mar 16, 2011

Fusion is the holy grail of nuclear power. It is clean and uses readily available fuel with no hazardous waster. Very smart people have been working on it for 50 years or more. The problem is that fusion takes place at temperatures far hotter than any known material can resist, so the only way to contain hydrogen plasma is to create an intense magnetic field. As far as I know, no laboratory has been able to create a fusion reaction that created more energy than was used up creating the magnetic field and heating the hydrogen to fusion temperatures.

Here's a link to an article about the ITER fusion power plant project your brother told you about.
Wikipedia ITER

Gun guru · Mar 16, 2011

Thanks for the link.

Very informative.

Anonymous-0 · Mar 16, 2011

Yes you are correct, wrote too fast without thinking, my mistake.

buickanddeere · Mar 16, 2011

Graphite is a very good neutron moderator. That is why Chernobyl had a run away when they inserted the emergency shut off rods.
Somebody had designed on graphite tips to the ends of the normally raised shut off roads. To improve neutron efficiency during normal operation.
When Chernobyl #4 started to run away a little bit. They dropped the shut off rods and the extra split second of moderation assisted the run away to the point of no return.
By the time the shutoff roads entered the reactor.She was past the point of using delayed neutrons for the chain reaction. And into using "prompt" neutrons.

buickanddeere · Mar 16, 2011

Tom H in Pa's link is very good. Wikipedia tends to be very close to the truth too the last I checked.
While gasoline is a fuel, so is U235. The different kinds of reactors vary as much as piston engine 2 or 4 stroke, carb, fuel injected or direct injected, gas turbine, steam boiler. Or a jug of gasoline tossed onto a bonfire.
Non enriched reactors like the Candu need to be poked in the behind with a sharp stick to get them to even run. Loose the any of the numerous conditions that encourage the chain reaction. The Candu takes a snooze and cools down.
Enriched reactors generally need the "brakes applied" to hold them back. No brakes, she runs away.
All said the Japanese reactors are going to be mostly embarrassing and expensive.
I've never understood why people up to their ears in muddy water. Are surprised it happened after they built in a flood plain.

MarkB_MI · Mar 16, 2011

I heard that the Japanese reactors in question were made by the folks at General Electric. You know, the ones who "make good things for living".

Ever heard of the Fort St. Vrain plant in Colorado? It used helium as its coolant. They had lots of problems and eventually closed it down 1992. As far as I know, it was the only reactor to be built with this design.
Ft. St. Vrain

buickanddeere · Mar 16, 2011

The British had some strange units that used CO2 gas for cooling.

PeterE · Mar 16, 2011

Soviets used liquid metal (sodium) on a few of their subs. I assume because metal is good at transferring heat.

But for my preference I'd rather not be underwater with a reactor cooled by an element that explodes when wet.

PeterE · Mar 16, 2011

Soviets used liquid metal (sodium) on a few of their subs. I assume because metal is good at transferring heat.

But for my preference I'd rather not be underwater with a reactor cooled by an element that explodes when wet.

old · Mar 16, 2011

So that is the one that is what the sun does. Hope no one ever does get it started because if they do we is dead and the earth will be another sun

bc · Mar 16, 2011

I see the japaness are looking for elderly volunteers to work on those damaged reactors. Apparently they will die before the years it takes for radiation to start causing health problems. Sounds like there is a future for B & D if something goes wrong at a reactor near him.

paul · Mar 16, 2011

So they put - um, little mirrors on the ends of the emergency rods to make the plant run better, but didn't realze the mirrors would mess up the one reason for those rods - to shut things down if it all went to heck?

It was, oh, let's hang them here, as long as these rods are dangling around in the way?

(I know not mirrors, an no nothing is that simple in this complex field...)

--->Paul

buickanddeere · Mar 16, 2011

Actually the way my chest is feeling tonight. After getting speared in the sternum with the end of a hockey stick eight days ago. You might get your wish.

KEB1 · Mar 16, 2011

"So that is the one that is what the sun does. Hope no one ever does get it started because if they do we is dead and the earth will be another sun"

Utter nonsense. Every hydrogen bomb that's ever been ignited involved a fusion reaction, and the earth hasn't been swallowed up yet. The earth does not have enough mass for gravity to create the temperatures and pressures necessary to sustain a fusion reaction, plus the earth is already mostly heavy elements that won't sustain a fusion reaction. The sun is mostly hydrogen, and is busily making heavier elements in the fusion reaction at its core.

Fusion reactions require extreme pressure and temperatures, like you find in the interior of the sun, to be sustained. Without both the temperature and pressure to force atoms together, the reaction will simply stop. That's why no one has been able to build a workable fusion power source yet...it takes more energy to ignite and sustain the reaction than we've been able to recover out of it. Some one will eventually solve that problem, but right now its still being worked on.

In simplistic terms, a hydrogen bomb uses a chemical explosive to compress fissionable material to critical mass, which then ignites a fission reaction, which it turn heats and compresses a sphere of deuterium (heavy hydrogen) enough to force the hydrogen atoms to fuse into helium, creating a fusion reaction.

Keith

buickanddeere · Mar 16, 2011

Sort of correct enough. Fast neutrons tend to bounce off other nucleus of other 235's.
If slowed by a moderator such as light water, heavy water or graphite.The neutrons stick to the U235 and make it as unstable. As a wife who has just been called "mother" by her husband.
Light water's drawback is that it absorbs some neutrons for a higher concentrate fuel is required to provide more targets.
Graphite burns which makes for a Chernobyl if the red hot material is exposed to air.
Heavy water costs huge $$$ to extract.

Mike M · Mar 17, 2011

I'm sure not a nuclear scientist,but I certainly think I could design a power plant to provide its own power so it didn't run out of electricty to run the cooling pumps.

Tom-TX · Mar 17, 2011

I am not a nuclear scientist either, but how on earth are you going to "provide its own power" during a shut down?? You have to cool it long after it is shut down and no longer producing electricity; thus you must have alternatively produced electricity during such procedures. Tom

glennster · Mar 17, 2011

mike, i worked at lasalle nuke plant in illinois in the mid 1970's during construction. lasalle has 2 reactors. in the aux buildings, there were massive locomotive engines that drove generators to provide back up power. if i remember each unit had 4 backup generators. also, it is possible to backfeed power from the grid to supply power to the plant. it was done during construction to supply power. we have quite a few nuke plants here in illinois, also coal fired, oil fired and natural gas peaker plants,

JML755 · Mar 17, 2011

(quoted from post at 19:29:13 03/16/11) The reactors in Japan are a very old, obsolete design. Better than what the Russians had in Chernobyl, but more like Three Mile Island than one that would be built today. New designs wouldn't have those problems cooling down after a power failure.
Reactor Design Discussion

Good article at that link. The media, politicians and tree-huggers are using this disaster to further their own agendas. The media will sensationalize anything (Lindsay Lohan, Charlie Sheen, etc) to get ratings and viewers and have no interest in actually telling a balanced, well-researched story. When something like this happens, they run to the library or do a google search to see who's written a book that will give them the dire headlines they are looking for. CNN is the worst.

And how many people have actually died as a result of the reactor problems? None that I've heard of, but thousands have died from the earthquake and tsunami. But CNN can't do "Breaking News" banners regarding the cleanup and recovery efforts. That doesn't produce the "edge of your seats" audience that they thrive on.

Ken Macfarlane · Mar 17, 2011

Thats why the new CANDU ACR 1000 just use heavy water right in the core. The old ones have huge amounts of heavy water to make it work making them more expensive than the US pwr reactors.

They are nice that they don't use enriched fuel, and can "burn" old nuclear weapon and other lower grade fissile material. Also, if they leak out or overheat, they tend to shut themselves down like Buick said.

You don't see more of them because they cost quite a bit more than the pwr and Canada hasn't been pushing them as strong as they used too. The other problem is some creative scientists in India used one sold there in a modified way to breed nuclear material that can be refined into an atom bomb.

RodinNS · Mar 17, 2011

Come on now... we hadn't heard about Charlie Sheen for a whole week until you brought that up...

Rod

Anonymous-0 · Mar 17, 2011

Canadian Candu reactors are very different from reactors such as Indian Point or Salem etc. On the news they talk about Japan's crisis. Worse than Three Mile Island but not as bad as Chernobyl. Okay On a scale of 1-100 Pa. is a 20 Chernobyl is off the chart. People still live in Pa. nobody lives near Chernobyl.People that go near there bring geiger counters to monitor the exposure. Chernobyl was bad. There was a bad one in the U.K. that was about a 40 on the scale.Chernobyl wont be livable for another hundred years. Dig some coal.

cadet trooper · Mar 17, 2011

My head hurts and I"m gonna build a bomb shelter!

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