quote Originally posted by phonedawgz: 4:22

Ok, you win that one, the talking head said burning.

quote Originally posted by maryjane: Especially human stupidity-proof. It is to be remembered, that Chernobyl happened because of mistakes made during an intentional planned test. And IIRC, addittional sand was brought in and dumped on the burning core via helo.

Russia's nuclear program = extreme stupidity multiplied by extreme arrogance

Chernobyl's design was inherently unstable
it used graphite to moderate the particles
it lacked containment
it lacked proper secondary and tertiary cooling methods
the operators weren't properly trained

Just to mention a few.

Basically anything Russia did was junk.

quote Originally posted by phonedawgz: How do you think thermal runaway applies here?

Thermal runaway refers to a situation where an increase in temperature changes the conditions in a way that causes a further increase in temperature, leading (in the normal case of an exothermic reaction) to a destructive result. It is a kind of positive feedback.
http://en.wikipedia.org/wiki/Thermal_runaway

quote Originally posted by dennis_6: Thermal runaway refers to a situation where an increase in temperature changes the conditions in a way that causes a further increase in temperature, leading (in the normal case of an exothermic reaction) to a destructive result. It is a kind of positive feedback. http://en.wikipedia.org/wiki/Thermal_runaway

And how do you think an increase in temperature will increase the reaction?

quote Originally posted by phonedawgz: And how do you think an increase in temperature will increase the reaction?

less cooling = more melting.

quote Originally posted by dennis_6: less cooling = more melting.

That fails the definition of thermal runaway.

quote Originally posted by dennis_6: Cup is analogy for people who can't understand a containment vessel can not stand excessive temps. I know the core isn't open ended, i know it doesn't hold standing water and requires a constant flow, and I know it contains fuel and control rods. I also know that the goo that can melt through the core and can melt through the containment vessel and the concrete of the building, and any damn thing it touches till it cools. This is where you seem to lack understanding. Now tell me what happens when this radioactive superheated goo comes in contact with mositure? I mean we have thousands of recording incidents for you to draw your knowledge on right? I am sure everybody knows its just harmless and will just cool and be concreted over once it cools. Zero chance something superheated could react with moisture and eject radioactive particles into the atmosphere, and there most certainly won't be contaminated soil to get blown by the wind. CNN said it can't happen, and they would know. They are staffed by experts in nuclear science. Yeah, thats the ticket. I am so glad your here to rehash cnn. Thanx. Look up thermal runaway.

Please try to be civil. Being uncivil only serves to detract from the quality of the discussion.

Thanks!

quote Originally posted by phonedawgz: That fails the definition of thermal runaway.

I disagree, the melting rods damaging the reactor core and containment vessel, making it impossible to cool. Leading to the rods temps increasing even higher. Similar to thermal runaway in electronics.

[This message has been edited by dennis_6 (edited 03-14-2011).]

Being that I'm not a nuclear engineer, and don't even play one on TV, I have a question for the more knowledgeable folks here:

If the core fuel structure fails in such a way the fuel's heat liquifies the fuel rods and the now liquid fuel rod material settles in the bottom of the containment vessel, how hot could it get and what is the temperature at which the containment structure loses its structural characteristics? Also, the sketch on the previous page showed thrus on the bottom of the containment vessel, are there actually items like pipes and such entering the vessel at the bottom? If so, what temperatures do these things melt at?

What features of reactor vessel design, passive or otherwise, prevent the fuel rods from generating enough heat to melt?

quote Originally posted by JazzMan: Please try to be civil. Being uncivil only serves to detract from the quality of the discussion. Thanks!

Your are correct sir, and I will either remove myself from this discussion or tone it down.

quote Originally posted by dennis_6: CNN said it can't happen, and they would know. They are staffed by experts in nuclear science. Yeah, thats the ticket. I am so glad your here to rehash cnn. Thanx.

I was noting the stuff CNN was telling us Saturday.

They initially said that Japan was handing out Iodine pills that would stop anyone from getting Radiation poisoning.
Then they said that Japan was not familiar with Nuclear power, and had no experience in dealing with a nuclear disaster.
Then in an interview with a Navy ship they asked how Japan would react when the US took charge. The Captain corrected then twice, telling them that they were simply there to assist Japan however Japan needed.

There were a few other things that made me , but those are the ones that are in my head at the moment.

Brad

quote Originally posted by dennis_6: I disagree, the melting rods damaging the reactor core and containment vessel, making it impossible to cool. Leading to the rods temps increasing even higher. Similar to thermal runaway in electronics.

The rod temps are not affected by a melted blob in the bottom of the reactor chamber. The same amount of heat needs to still be dissipated.

From your 'source'



There is no increase in reaction rate caused by heat. Melting the rods will not increase the reaction rate. Not a thermal runaway.

Yes a melted core at the bottom of the reactor vessel will be harder to cool. It however does not increase the reaction rate. It fails the definition.

[This message has been edited by phonedawgz (edited 03-14-2011).]

quote Originally posted by phonedawgz: The rod temps are not affected by a melted blob in the bottom of the reactor chamber. The same amount of heat needs to still be dissipated. From your 'source' There is no increase in reaction rate caused by heat. Melting the rods will not increase the reaction rate. Not a thermal runaway. Yes a melted core at the bottom of the reactor vessel will be harder to cool. It however does not increase the reaction rate. It fails the definition.

Your still hung up on trying to apply thermal runaway to the actual nuclear reaction and not to a reactor meltdown. It doesn't increase the nuclear reaction. It does apply to the meltdown scenario.

quote Originally posted by twofatguys: I was noting the stuff CNN was telling us Saturday. They initially said that Japan was handing out Iodine pills that would stop anyone from getting Radiation poisoning. Then they said that Japan was not familiar with Nuclear power, and had no experience in dealing with a nuclear disaster. Then in an interview with a Navy ship they asked how Japan would react when the US took charge. The Captain corrected then twice, telling them that they were simply there to assist Japan however Japan needed. There were a few other things that made me , but those are the ones that are in my head at the moment. Brad

The iodine pills do not "stop anyone from getting radiation poisoning". They do help to prevent the thyroid from storing radioactive iodine. They do that by saturating the thyroid with non-radioactive iodine. Having radioactive isotopes stored in your body isn't good. It sill doesn't prevent other radioactive isotopes from being absorbed, and it doesn't stop radioactive rays caused from decaying radioactive particles.

quote Originally posted by JazzMan: Being that I'm not a nuclear engineer, and don't even play one on TV, I have a question for the more knowledgeable folks here: If the core fuel structure fails in such a way the fuel's heat liquifies the fuel rods and the now liquid fuel rod material settles in the bottom of the containment vessel, how hot could it get and what is the temperature at which the containment structure loses its structural characteristics? Also, the sketch on the previous page showed thrus on the bottom of the containment vessel, are there actually items like pipes and such entering the vessel at the bottom? If so, what temperatures do these things melt at? What features of reactor vessel design, passive or otherwise, prevent the fuel rods from generating enough heat to melt?

Three mile island would have been at meltdown in 30-60 minutes if the rods have been exposed that long. I have heard the temps required is around 2700 degrees. I also am not a nuclear engineer, nor do I play one on tv. I am sure someone will google and find your answers. I do know the control rods and the extremely pressurized flow of coolant keeps the cores temps stable.

[This message has been edited by dennis_6 (edited 03-14-2011).]

quote Originally posted by phonedawgz: The iodine pills do not "stop anyone from getting radiation poisoning". They do help to prevent the thyroid from storing radioactive iodine. They do that by saturating the thyroid with non-radioactive iodine. Having radioactive isotopes stored in your body isn't good. It sill doesn't prevent other radioactive isotopes from being absorbed, and it doesn't stop radioactive rays caused from decaying radioactive particles.

I know that, because I switched over to Fox news, and their "Expert" said basically the same thing as you just put. I didn't know about the pills before that. Fox said they just block one type of radiation though, and hinted that the pills were more to make the people feel better (placebo effect) than anything. \

Brad

quote Originally posted by phonedawgz: Well I'm glad you agree that this isn't a potential thermal runaway situation.

From a practical point of view, is there a difference between a thermal runaway event and a runaway fission event? I understand the former is more chemical where the heat feeds back into the process, resulting in an increasing amount of energy release, whereas the latter, once full criticality is reached has a fixed but very high rate of energy output. I think Dennis_6 is trying to understand it in terms of a runaway exothermic reaction which, though similar in end rsult, isn't technically identical. Am I seeing it right? Is it right to assume the rate of energy release by a molten fuel rod puddle is limited by the relatively small percentage of fuel in the mix? I've seen fuel rod fuel percentages discussed as low to mid single digit percentages, is that correct?

------------------
Bring back civility and decorum!

It's possible to understand someone's point of view without accepting it. It's possible to disagree with someone without being rude and nasty about it. Sure it's hard, but nothing worth doing is ever easy, is it?

Replying to Jazzman

The cooling water in US (and Japan) reactors is part of the nuclear reaction chain. The water 'moderates' or slows down the particles so they are at the proper energy level to strike the next atom and keep the chain going. With a drop in water, the nuclear reaction stops. Again you still need to deal with the decay heat that is still being produced. A negative feedback loop.

Chernobyl's graphite design actually worked in reverse. As coolant was lost, the reaction increased. A positive feedback loop. A HUGE flaw in the design.

quote Originally posted by JazzMan: From a practical point of view, is there a difference between a thermal runaway event and a runaway fission event? I understand the former is more chemical where the heat feeds back into the process, resulting in an increasing amount of energy release, whereas the latter, once full criticality is reached has a fixed but very high rate of energy output. I think Dennis_6 is trying to understand it in terms of a runaway exothermic reaction which, though similar in end rsult, isn't technically identical. Am I seeing it right? Is it right to assume the rate of energy release by a molten fuel rod puddle is limited by the relatively small percentage of fuel in the mix? I've seen fuel rod fuel percentages discussed as low to mid single digit percentages, is that correct?

Thermal runaway and runaway fission are different. Runaway fission sounds like a nuclear explosion to me, thermal runaway can occur in electronics, batteries, chemical reactions. I wasn't stating that the fuel rod would become hotter because of a reaction, but due to a potential breach of the containment vessel causing it impossible to keep pressurized sea water on the core, making it a self feeding cycle until the rods melted through the vessel.

[This message has been edited by dennis_6 (edited 03-14-2011).]

quote Originally posted by twofatguys: I know that, because I switched over to Fox news, and their "Expert" said basically the same thing as you just put. I didn't know about the pills before that. Fox said they just block one type of radiation though, and hinted that the pills were more to make the people feel better (placebo effect) than anything. \ Brad

They do some good. Again it's more that you don't want radioactive isotopes stored in your body. The thyroid stores iodine.

quote Originally posted by phonedawgz: They do some good. Again it's more that you don't want radioactive isotopes stored in your body. The thyroid stores iodine.

You should also warn the pills can cause harm, so they shouldn't be taken unless needed.

Yes a runaway nuclear event would be a bomb. That can't happen with the low concentrations of uranium used in the reactors.

quote Originally posted by JazzMan: Being that I'm not a nuclear engineer, and don't even play one on TV, I have a question for the more knowledgeable folks here: If the core fuel structure fails in such a way the fuel's heat liquifies the fuel rods and the now liquid fuel rod material settles in the bottom of the containment vessel, how hot could it get and what is the temperature at which the containment structure loses its structural characteristics? Also, the sketch on the previous page showed thrus on the bottom of the containment vessel, are there actually items like pipes and such entering the vessel at the bottom? If so, what temperatures do these things melt at? What features of reactor vessel design, passive or otherwise, prevent the fuel rods from generating enough heat to melt?

I'm not the guy to answer all that, but from my past discussions with a friend employed at the South Texas plant, yes--there are coolant pipes entering and leaving the containment vessel from below. They have had some leakage problems with them in the past--as far back as 2003, which is public knowledge, and I believe one of the Vermont plants had similar problems. Evidently, there is a way to get to these pipes from below, as they were fixed at STNP.

I have no idea what the melt point of any of it is.

Anytime you have high pressure steam and high pressure water you are going to have issues with leaking sometime. Problems are managed not solved.

quote Originally posted by twofatguys: I was noting the stuff CNN was telling us Saturday. They initially said that Japan was handing out Iodine pills that would stop anyone from getting Radiation poisoning. Then they said that Japan was not familiar with Nuclear power, and had no experience in dealing with a nuclear disaster. Then in an interview with a Navy ship they asked how Japan would react when the US took charge. The Captain corrected then twice, telling them that they were simply there to assist Japan however Japan needed. There were a few other things that made me , but those are the ones that are in my head at the moment. Brad

Yes, but they said it with a British accent!

quote Originally posted by phonedawgz: They do some good. Again it's more that you don't want radioactive isotopes stored in your body. The thyroid stores iodine.

They primarily block the uptake of radioactive iodine isotopes, which can cause thyroid cancer, by pre-filling the thyroid's iodine storage. However, they do nothing for cesium and strontium isotope uptake which are far more dangerous. Thyroid cancer is probably one of the most easily-treated internal cancers with survival rates in the mid to high 90% range. Ironically, the treatment for thyroid cancer is a large dose of radioactive thyroid isotopes which kills the thyroid, cancer and all, leaving one dependent on thyroid pills for the remainder of life. Only a few percent of thyroid tumors fail to respond to this treatment.

quote Originally posted by phonedawgz: I don't think anyone in Japan is reading PFF. We use iodine to purify water when camping in the US.

More for people in California, that might think its a good idea to take a few "just in case".
Iodism
# Patients who use potassium iodide may experience side effects such as hives, nausea, vomiting and swelling. These side effects typically go away as the body adjusts to the medication, but in some cases, long-term users develop a more serious condition called iodism. Iodism may involve skin eruptions, runny nose, severe headache, irritation of mucous membranes, and sometimes weakness, anemia and depression.
Pregnant and Breastfeeding Women
# Use of potassium iodide by pregnant or breastfeeding women can cause fetal goiter and hypothyroidism in the fetus or infant. It's usually not recommended for use by pregnant or breastfeeding women. However, if authorities recommend use of potassium iodide in a radiation emergency, the Centers for Disease Control does say that pregnant and breastfeeding women, as well as infants, should take an appropriate dose. The CDC says they should avoid more than one dose if possible.

Read more: Potassium Iodide Hazards | eHow.com http://www.ehow.com/list_74...s.html#ixzz1GcFVjGsx

Believe whatever you want to. You are going to anyways.

Breaking 2nd explosion at reactor 2 according to Fox News containment breach!!!
No link yet, was just on TV. If this is so, Reactor 2 has went into full meltdown!!

From the "talking head".. The last explosion came from within the containment vessel. This power plant has the worst safety record and the company has a history of lying. What a combination, we are operating where all answers are theoretical and the company in charge appears to be incapable of managing the emergency or truth.

quote Originally posted by Wudman: From the "talking head".. The last explosion came from within the containment vessel. This power plant has the worst safety record and the company has a history of lying. What a combination, we are operating where all answers are theoretical and the company in charge appears to be incapable of managing the emergency or truth.

Lol, you should change your username to talkinghead :P