Let see, the worse it was at Tokyo was 4 times higher then background (0.8 uSv) and Tokyo is 150 miles away from the plant, how fair is the USA, oh 5,000 miles, so I think its plausible.
Japanese N-Plant Explosion
- Thread starter ULTRA
- Start date
Let see, the worse it was at Tokyo was 4 times higher then background (0.8 uSv) and Tokyo is 150 miles away from the plant, how fair is the USA, oh 5,000 miles, so I think its plausible.
i don't it will be high. I don't think it will even be significant, but some is bound to turn up somewhere..
Why read hype when you can get the facts from the source:
http://translate.google.com/transla...en&u=http://www.tepco.co.jp/cc/press/&act=url
Radiation levels outside the plant is now at 268.7 μSv, has been dropping steadily since March 16.
That would actually work, from what I'm reading...but only for a little while, A few days? (asking) until the core converted the Xenon into Xe136?
Which would at least give you a window of time to get pumps online to cool the core...
Edited to add-the wikipedia article says a half-life of 50 hours in a nuclear reactor
http://en.wikipedia.org/wiki/Iodine_pit
http://en.wikipedia.org/wiki/Xenon-135
By the time it gets to the USA it might not even be detectable, think about it its so dilute by the time the worse of it got to Tokyo it was just 4 times above background, the USA is 33 times further away. By the way Nuclear bomb tests in the pacific have given off way more fallout than this.
The problem with these reactors is decay heat. Nuclear fission has already been inhibited but there so much radioactive material produced by the fission in the reactors that it needs cooling to keep from melting. Passive safe 3rd generation reactors can keep the reactors cool after shut down without pumps or attention. Lead or salt cooled reactors don't need cooling post shutdown quite the opposite in fact decay heat is a good thing as it prevents freeze up of the molten coolant.
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Yeah Bikini Attoll and Christmas Island were bombed nearly to destruction. There is little for the US to fear, if anything. If none turned up the conspiracy theorists would say it's a cover-up. I'm sure they'll find something however innocuous...
Actually, I was thinking of a different isotope, I though Xe-124 would have a sufficient cross section to do the job, and it has the advantage of being stable, so you can store it indefinitely, but I misread something I was looking at and thought that Uranium had a small capture cross section, but yes, you're right about Xenon-135.
As it turns out Mercury would work better (environmental considerations aside). One of its stable Isotopes (Hg-196) has a neutron capture cross section of 3080 Barns, and another has a cross section of 2150 barns (Hg-199). Hg-196 is almost as effective as Boron at quenching nuclear reactions. Mercury might even make an effective emergency coolant. It has a lower heat capacity than water, so that's not so good, but being a metal, I think it has a higher thermal conductivity, which might be useful.
Of course, the biggest problem with Mercury is that you've then got the possibility of it forming Amalgams with the fuel, the cotrol rods, and the reaction vessel.
I found this linked at one of the blogs I follow:
http://www.ucsusa.org/nuclear_power...isis-japan-telepress-transcript-03-15-11.html
And found it fairly clear.
http://www.ucsusa.org/nuclear_power...isis-japan-telepress-transcript-03-15-11.html
And found it fairly clear.
The Three Mile Island accident released an enormous amount of Xenon gas, but only a tiny amount of Iodine.
And virtually nothing else.
Does anyone know why so little Radioactive Iodine was released at Three Mile Island?
In comparison with the Chernobyl accident, where it was a major pollutant.
Perhaps it was the graphite fire that pulled out the heavier elements in smoke.
Does anyone know what is being released at Fukushima?
The following is an explanation of what happened at Chernobyl.
Is the same thing happening at Fukushima?
Iodine-135 is a fission product of uranium with a yield of about 6%.[3] This 135I decays with a 6.7 hour half-life to 135Xe. Thus, in an operating nuclear reactor, 135Xe is being continuously produced. 135Xe has a very large neutron absorption cross-section, so in the high neutron flux environment of a nuclear reactor core, the 135Xe soon absorbs a neutron and becomes stable 136Xe. Thus, in about 50 hours, the 135Xe concentration reaches equilibrium where its creation by 135I decay is balanced with its destruction by neutron absorption.
When reactor power is decreased or shut down by inserting neutron absorbing control rods, the reactor neutron flux is reduced and the equilibrium shifts initially towards higher 135Xe concentration. The 135Xe concentration peaks about 11.1 hours after reactor power is decreased. Since 135Xe has a 9.2 hour half life, the 135Xe concentration gradually decays back to low levels over 72 hours.
The temporarily high level of 135Xe with its high neutron absorption cross-section makes it difficult to restart the reactor for several hours. The neutron absorbing 135Xe acts like a control rod reducing reactivity. The inability of a reactor to be started due to the effects of 135Xe is sometimes referred to as xenon precluded start-up. The period of time where the reactor is unable to override the effects of 135Xe is called the xenon dead time.
If sufficient reactivity control authority is available, the reactor can be restarted, but a xenon burn-out transient must be carefully managed. As the control rods are extracted and criticality is reached, neutron flux increases many orders of magnitude and the 135Xe begins to absorb neutrons and be transmuted to 136Xe. The reactor burns off the nuclear poison. As this happens, the reactivity increases and the control rods must be gradually re-inserted or reactor power will increase. The time constant for this burn-off transient depends on the reactor design, power level history of the reactor for the past several days, and the new power setting. For a typical step up from 50% power to 100% power, 135Xe concentration falls for about 3 hours. [4]
Failing to manage this xenon transient properly caused the Chernobyl reactor power to overshoot ~100x normal causing a steam explosion.
http://en.wikipedia.org/wiki/Xenon-135
And virtually nothing else.
Does anyone know why so little Radioactive Iodine was released at Three Mile Island?
In comparison with the Chernobyl accident, where it was a major pollutant.
Perhaps it was the graphite fire that pulled out the heavier elements in smoke.
Does anyone know what is being released at Fukushima?
The following is an explanation of what happened at Chernobyl.
Is the same thing happening at Fukushima?
Iodine-135 is a fission product of uranium with a yield of about 6%.[3] This 135I decays with a 6.7 hour half-life to 135Xe. Thus, in an operating nuclear reactor, 135Xe is being continuously produced. 135Xe has a very large neutron absorption cross-section, so in the high neutron flux environment of a nuclear reactor core, the 135Xe soon absorbs a neutron and becomes stable 136Xe. Thus, in about 50 hours, the 135Xe concentration reaches equilibrium where its creation by 135I decay is balanced with its destruction by neutron absorption.
When reactor power is decreased or shut down by inserting neutron absorbing control rods, the reactor neutron flux is reduced and the equilibrium shifts initially towards higher 135Xe concentration. The 135Xe concentration peaks about 11.1 hours after reactor power is decreased. Since 135Xe has a 9.2 hour half life, the 135Xe concentration gradually decays back to low levels over 72 hours.
The temporarily high level of 135Xe with its high neutron absorption cross-section makes it difficult to restart the reactor for several hours. The neutron absorbing 135Xe acts like a control rod reducing reactivity. The inability of a reactor to be started due to the effects of 135Xe is sometimes referred to as xenon precluded start-up. The period of time where the reactor is unable to override the effects of 135Xe is called the xenon dead time.
If sufficient reactivity control authority is available, the reactor can be restarted, but a xenon burn-out transient must be carefully managed. As the control rods are extracted and criticality is reached, neutron flux increases many orders of magnitude and the 135Xe begins to absorb neutrons and be transmuted to 136Xe. The reactor burns off the nuclear poison. As this happens, the reactivity increases and the control rods must be gradually re-inserted or reactor power will increase. The time constant for this burn-off transient depends on the reactor design, power level history of the reactor for the past several days, and the new power setting. For a typical step up from 50% power to 100% power, 135Xe concentration falls for about 3 hours. [4]
Failing to manage this xenon transient properly caused the Chernobyl reactor power to overshoot ~100x normal causing a steam explosion.
http://en.wikipedia.org/wiki/Xenon-135
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Why not stay on the coast and eat the seaweed in situ.
Another thought on the Geophysics question.
These plants were built in the 70's, and I'd imagine that the main surveys were done in the late 1960's.
I'm wondering whether resurveying in the 80's or 90's would have uncovered a potential problem?
These will be happy days for Geophysicists, if Governments insist on companies resurveying old sites with more modern equipment and programs.
I know that oil and gas people (for example) will rerun old data for years using new programs to extract more information.
It is in the interests of O&G companies to find new reserves, and it is against the interest of the Nuclear energy industry to find problems.
If they did update their information would the 1960's raw data be good enough?
Or would they have to take new soundings?
And were they required to do so?
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Trippy:
I seem to recall reading recently that the reactor runs at 285MPa which is about 2800 Atmospheres, or 41,300 PSI.
Hey Trippy, stop arguing with Trippy!
You don't know what you are dealing with!
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Why not stay on the coast and eat the seaweed in situ.
Another thought on the Geophysics question.
These plants were built in the 70's, and I'd imagine that the main surveys were done in the late 1960's.
I'm wondering whether resurveying in the 80's or 90's would have uncovered a potential problem?
Well, the problem is that the quake was unprescedented. There's never been one like it in modern times. It was thought that a quake of this magnitude was beyond the scope of what quakes could do. This one's re-writing all the books. I don't think this quake could reasonably have been predicted, and let's face it, the Japs have had plenty of experience to base thier models on. But the N-plants survived the quake, it was the Tsinami that knocked out the cooling pumps, and there was no way anyone could have predicted such a massive wave. If it was thought possible, a lot more people would have lived.
@Ultra.
I don't want to argue with Trippy, because he knows a hundred times more about this subject than I do.
I just find it hard to believe that if an exhaustive geophysical survey had been done off this part of Japan's coast, say in the last 5 years, that it would not have pointed to a potential problem.
A 9.0 earthquake? The evidence must have been there for anyone who wanted to delve deep enough, surely.
I don't want to argue with Trippy, because he knows a hundred times more about this subject than I do.
I just find it hard to believe that if an exhaustive geophysical survey had been done off this part of Japan's coast, say in the last 5 years, that it would not have pointed to a potential problem.
A 9.0 earthquake? The evidence must have been there for anyone who wanted to delve deep enough, surely.
Buffalo Roam
Registered Senior Member
The Russian reactor had a totally different design, and used a different grade of fuel.
Plus, Chernobyl was due human-caused error, causing a steam explosion.
This resulted in a graphite fire which was uncontained, and the smoke lofted radioactive matter high into the atmosphere.
Three Mile Island was a undetected leak that allowed the water level around the nuclear fuel, to drop, exposing the fuel rods, resulting in a third of it melting.
The big difference between Chernobyl, and Three Mile Island was that the reactor vessel did not fail and that contained almost all of the radioactive material.
Radiation thought to originate in Japan detected in US, says Reuters. Miniscule levels of radiation though - in no way harmful to humans. http://reut.rs/gyMI3P
Maybe So. The enquiry will be interesting, and will help people to be better informed.
If there is criminal negligence, it will be uncovered.
Whatever happens, the world is desperate for low carbon energy, and I can't see nuclear power being sidelined for long.
Regarding increase in background radiation.
It's not just a problem for one generation.
Genetic problems are cumulative aren't they?
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