Fukushima - will there be a problem Alaska? (Chicken: construction, safety)

[Dakster]

Turn off the faucet and boom...

[Rance]

Might be the best way to end the flow? Blow it up and be done with it.

[yanvit]

Maybe we evolved from monkeys exposed. The evolution continues! we are waiting for a new world.

[Dakster]

Originally Posted by Rance

Might be the best way to end the flow? Blow it up and be done with it.

I think that would be a really bad idea. Radioactive fallout is not good.

[richelles]

Reading the material posted here reinforces my belief that few people fully understand the concepts of nuclear reactions. One thing is that creating a nuclear reaction isn't easy. Look at the years it took to actually become nuclear proficient. The thing most people think they know about nuclear reactions is summarized by the term "Nuclear Meltdown". The first thing we need to understand is during a nuclear meltdown the amount of nuclear fuel involved is directly related to the seriousness of the incident. A nuclear criticality excursion can be caused by a number of different things. Loss of coolant is the most obvious cause which could be from a number of causes such as low flow or loss of coolant pressure. Damage to the nuclear fuel could range from a local meltdown of a fuel rod to meltdown of an entire fuel assembly. The latter is close to what the so called "China Syndrome" was purported to be where the liquid core melts through the reactor vessel and into the Earth until it reaches the water table. If a criticality excursion occurs there are a number of safeguards known as "Emergency Core Cooling Systems" (ECCS) built into reactors ranging from lowering the control rods by gravity, flooding the area with neutron absorbing material, or dilution by debris bed formation created by melting the components in the reactor vessel until the inability of the chain reaction to continue is reached. This goes back to the first statement above where even getting to a critical mass is difficult. In the Fukushima incident there is a possibility the nuclear fuel has melted through the base of the reactor vessel and the resulting hydrogen explosion has allowed the radioactive products to escape into the environment. But the more exposure to materials that can create a debris bed the greater the dilution that is occurring rendering the continuation of a chain reaction impossible. So at this point the danger of a continued chain reaction is remote and the function of nuclear decay is rapidly removing the radiation danger. Two important factors in dealing with radiation are time and distance. The half life of the nuclear isotopes is removing the radiation and how far away you are from the source is directly related to the exposure. So if you're a long way from the source and it has taken time for the material to reach you the possibility of contamination is getting smaller. So even Chicken Little should relax now and hope they get the mess cleaned up in due course.

[Rance]

Thank you richelles!

[Hawknest]

So far as I know there have been three such meltdowns - a partial at TMI, full blown at Chernobyl and Fukushima. Tepco is starting the process to move the fuel rods to a safer building. They said last night the large debris has been removed from the pool. However, fisson will occur if the rods touch each other or bump into the debris still in the pool.

[Rance]

So thats bad? If these fuel rods touch each other? They explode? Or turn white hot and melt through anything including the earth?

[Frostnip]

Originally Posted by Rance

So thats bad? If these fuel rods touch each other? They explode? Or turn white hot and melt through anything including the earth?

Cross the streams - YouTube

[richelles]

Originally Posted by Hawknest

So far as I know there have been three such meltdowns - a partial at TMI, full blown at Chernobyl and Fukushima. Tepco is starting the process to move the fuel rods to a safer building. They said last night the large debris has been removed from the pool. However, fisson will occur if the rods touch each other or bump into the debris still in the pool.

Hawknest has fouled his nest again by pretending to have some knowledge about nuclear reactions. There have been three nuclear incidents that were classified as major; rating a place on the scale of such incidents. TMI was serious but only caused a small amount of radioactive material to be released. The site has been cleaned up and there is a report available on the actual results. Chernobyl was a totally different type of nuclear accident being it was a graphite moderated reactor that when a steam explosion exposed the carbon to air it burned in a manner similar to burning coal. The smoke from the burning radioactive debris was widely scattered and caused major problems with radioactive contamination. A concrete cap was poured over the entire containment area and to the best of my knowledge is still in place. I believe there have been some drill probes into the remains of the reactor but only limited information is available about the current situation. Fukushima was a series of six interconnected GE Boiling Water nuclear reactors which seemingly was built on the cheap which suffered massive equipment failure as a result of an earthquake and the resulting Tsunami. Three of the reactors were either defueled or in cold shutdown and present a lesser problem than the other three which went into a SCRAMED event during the earthquake as they were designed to do. The damage was from residual heat which couldn't be controlled after the emergency generators were overwhelmed by the tidal wave resulting from the off shore earthquake. The lack of proper attention to the suitability of the siting of the generators by not making the wall high enough to protect the generators from the results of the Tsunami was the proximate fault.

Hawknest has proven again his complete lack of knowledge about nuclear reactions with his statement to wit : "fission will occur if the rods touch each other or bump into the debris ... ..." There might be normal decay which always occurs in a fuel rod; but I defy him to produce any credible citation that supports an assertion that a chain reaction will be the result of such chance touching. Building a critical mass that will support a chain reaction is a serious business that does not depend on chance or dumb luck such as Hawknest seems to be full of. A single nuclear fuel rod will, as a result of natural decay, have some reactions but without a critical mass positioned so it can capture the released neutrons there is no chain reaction fission. Actually being Hawknest has some carbon, oxygen and other fissionable isotopes in his full body load of radioactive isotopes he could also cause fission but without a chain reaction it just amounts to normal half life decay. No matter how much you touch one fuel rod to another without an intelligent design of a critical mass no chain reaction is possible. This is a very poor example of how dangerous a busted fuel rod actually is.