What Is A Nuclear Meltdown?

[Snipergod87]

[citation][nom]mlopinto2k1[/nom]Zirconium is mainly used.[/citation]
I stand corrected, My information is a litle old.

 

[bayouboy]

[citation][nom]LePhuronn[/nom]And the Japanese haven't just filled up the containment chamber with boron powder why? Standard failsafe equipment over here in the UK (IIRC, of which I probably don't).Kills the reactor stone dead yes, but the fission reaction stops as every particle gets soaked up.[/citation]

They did, but the daughter products continue to generate heat as they decay and there are no means to stop this. Since the primary cooling system is still nonoperational, they are having to use the reactors primary cooling circuit as the sole method of cooling the reactor, and this is an extremely difficult task.

The exchange of neutrons has long since ceased in all the reactors.

 

[Guest]

[citation][nom]Snipergod87[/nom]I stand corrected, My information is a litle old.[/citation]

Actually you stand correct. Zirconium is used in the fuel rod cladding because it absorbs so few neutrons, exactly the opposite effect to what you want in a control rod which, as you point out, mainly use boron now due to it's excellent neutron absorption. Hence the emergency cooling of the reactor cores using seawater and boric acid, a convieniently water-soluble boron compound.

 

[bigcatface]

well fcuk me sideways, turns out all tomsnerds are nuclear scientists too!
if we ever actually run out of intelligent people, i'm sure we could turn to you guys instead.
bad news for japan though, i do hope they manage to fix themselves sharpish!

 

[maestintaolius]

[citation][nom]jnc852[/nom]Hmm....I bet coal fired generation isnt looking so bad in the eyes of many anymore.[/citation]
Considering how many people coal gathering kills per year, not really.

 

[Guest]

Whoever made this needed to check their work more carefully. The Chernobyl reactor was of the RBMK design and thus had no containment building - that was why so much radiation was spread.

 

[caamsa]

Ok let us put this in perspective.......the tidal wave killed tens of thousands and we are worried about a dang nuclear power plant. Nothing rivals mother nature.

 

[DokkRokken]

[citation][nom]maestintaolius[/nom]Considering how many people coal gathering kills per year, not really.[/citation]

Not to mention the illness and deaths caused by burning the stuff, as well as the environmental contamination.

 

[fancarolina]

That depends on what your definition of is ... is.

 

[Ciuy]

thats what you get by building a NUCLEAR REACTOR near a fault line on the shore of the largest ocean.

 

[beayn]

So I'm a little confused. I keep hearing that 4 reactors can possibly melt down and two reactors are critical. The confusing part is, are all 6 reactors at the same nuclear power plant or are there 6 separate plants that have reactors with issues? There's so much information on this out there I don't have time to sift through it all.

 

[jamoise]

got this from an article thats doing circulation atm.


"Can this end up like Chernobyl?

No, it cannot. for several reasons .

Chernobyl used graphite as a neutron moderator and water as a coolant. For complicated reasons, this meant that as the coolant heated up and converted to steam, the fission reaction intensified, converting even more water to steam, leading to a feedback effect. The Fukushima reactors use water as both the coolant and the neutron moderator, which means that as the water heats up and converts to steam, the reaction slows down instead. (The effect of the conversion of water coolant to steam on the performance of a nuclear reactor is known as the "void coefficient", and can be either positive or negative.)

Chernobyl was designed so that as the nuclear fuel heated up, the fission reaction intensified, heating the core even further, causing another feedback effect. In the Fukushima reactors, the fission reaction slows down as the fuel heats up. (The effect of heating of the nuclear fuel on the performance of a nuclear reactor is known as the "temperature coefficient", and can also be positive or negative.)

Chernobyl's graphite moderator was flammable, and when the reactor exploded, the radioactive graphite burned and ended up in the atmosphere. The Fukushima reactors use water as a neutron moderator, which is obviously not flammable."

In other words, if the system runs out of water, the reaction will "shutdown" and go into decay mode, where the fuel rods will melt but not go out of control, and the containment vessel is designed to handle such an occurance. it will also mean the reactor is a write off. currently what they are trying to do is save the reactor, which if they cant, they will just feed sea water into it, like they have 2 of the others, and the reactor will be a write off, costing billions of dollars to replace.

 

[vvarreng]

UN nuclear counsel said the soil was unstable for a Nuclear power plant. Not saying Japan was wrong for building them, but this is what happens when you take any risk. No expert here just stating the simple.

 

[christop]

I don't think the people at the power plant are not being totally honest about the problems. I mean come on one blew another one blew one is on fire. I also saw on the news they filled one with water and it didn't fill up sound like a breach to me. I think they should be totally honest and stop making out like they have this under control. I am shocked that all that hydrogen gas that is venting doesn't ignite from something. I would not trust them saying o yeah it just like getting an x-ray. Any ways I wish them luck...

 

[sonofliberty08]

[citation][nom]jnc852[/nom]Hmm....I bet coal fired generation isnt looking so bad in the eyes of many anymore.[/citation]
the natural gas plant is way better ......

 

[m0j0j0j0]

[citation][nom]sonofliberty08[/nom]the natural gas plant is way better ......[/citation]

nah, geothermal powerplants are the way to go

 

[f-14]

[citation][nom]cjl[/nom]There's a lot of misinformation here. Although a meltdown will severely damage a powerplant, modern powerplants are unable to have anything like what happened at Chernobyl. Chernobyl had no containment vessel, and a poor design which resulted in an explosion in the core, spreading radioactive waste far and wide. A modern reactor, if it were to melt down, would still have everything in the containment vessel. It would just be in a molten puddle in the bottom of the containment vessel. No substantial radiation would escape, and there would be effectively no danger to the surrounding population. For a much more detailed explanation of what's going on in the reactors right now, see here:http/morgsatlarge.wordpress.com/ [...] -reactors/[/citation]
^5. don't jump the gun before inspections are carried out inside the reactor by people and not some poor quality camera images. that earth quake was strong enough to crack every layer of casing.
2 reactors at 2 different power plants and a thrid is on the frits at fukushima and a 4th is severly damaged and on fire and spewing radiation.
http/news.yahoo.com/s/ap/ap_on_bi_ge/as_japan_earthquake_nuclear_crisis

those rods should be stable and under control by now yet there are still problems occuring. something sounds fishy and given the jap history of covering terrible things up, i'm starting to get concerned their pride and honor are getting in the way.

 

[jamoise]

[citation][nom]f-14[/nom]^5. don't jump the gun before inspections are carried out inside the reactor by people and not some poor quality camera images. that earth quake was strong enough to crack every layer of casing.2 reactors at 2 different power plants and a thrid is on the frits at fukushima and a 4th is severly damaged and on fire and spewing radiation.http/news.yahoo.com/s/ap/ap_on_b [...] ear_crisisthose rods should be stable and under control by now yet there are still problems occuring. something sounds fishy and given the jap history of covering terrible things up, i'm starting to get concerned their pride and honor are getting in the way.[/citation]

sorry, but, ill start believing more of what I read, when its not from a news source who are out to sensationalize to bring readers to their website/buy newspapers. At the moment, I trust news websites about as much as I trust Barny the dinosaur, to deliver the latest on love compatibility between himself and yourself.

 

[jamoise]

also, even though the SCRAM system was implemented through all the reactors (which effectively shuts down the system), theres still decay heat, and unless coolant is continously pushed through the system. it will still "melt" the fuel rods. which will damage the reactor making it unusable again, the amount of containment and safety in place means that even after a magnitude 9 earthquake and a tsunami and 3 hydrogen explosions, the safety of the system is still intact. if you read up on how the reactors in Japan work, then you will see why.

 

[belardo]

[citation][nom]cjl[/nom]Although a meltdown will severely damage a powerplant, modern powerplants are unable to have anything like what happened at Chernobyl. Chernobyl had no containment vessel, and a poor design which resulted in an explosion in the core, spreading radioactive waste far and wide. A modern reactor, if it were to melt down, would still have everything in the containment vessel.[/citation]

Except there really aren't many "modern" reactors. Most of these are 40+ year old designs. Of course, you are right that these are nothing like the Chernobyl fluster cuck.