Migration rates of plutonium at the Savannah River weapons plant.

Here is an article describing the migration of plutonium released on soils typical of South Carolina. It is found in Environ. Sci. Technol. 2004, 38, 5053-5058 and the title of the article is "Influence of Oxidation States on Plutonium Mobility during Long-Term Transport through an Unsaturated Subsurface Environment."



Some observations: The plutonium travelled on average about 1 cm per year in South Carolina, with the majority having travelled far less far the leading edge of the contamination. Ninety-five percent moved less than 1 cm per year, in fact 95% moved 1 mm per year.

Focusing only the leading edge, we see that in one half-life of plutonium-239, 24,100 years, the plutonium would have travelled about 241 meters, all things remaining constant. For it to travel 1 km will require 100,000 years. Because the half-life of ²³⁹Pu is 24110 years, by the time any atom of plutonium has travelled 1 km, 94% of its sister atoms will have decayed. Since every ten centimeters attentuates the concentration by 95%, and because 100,000 such attenuations are involved, only a few atoms will actually make it that far, if any. The 100,000 years will involve 10,000 periods during which the migrating species is reduced to 5% of what it previously was. Thus we have 0.5^10,000 which is approximately equal to zero.

Somehow I don't think that any plutonium that is wasted by placing it in Yucca Mountain is going to find its way to Los Angeles. This is especially the case because no one is going to just dump it on the ground. It will be contained in stable glass.

You may know this, but here is how you calculate how much plutonium will remain after 100,000 years. To get the decay constant you divide ln(2) by the half life, 24,110 years. The answer is approximately 2.87 X 10^-5. The radioactive decay law says N_t = N_oe^-kt where k is the decay constant, t is the time N_o is the amount initially present N_t is the amount present at time t. At t = 100,000 years, this works out to N_t = 0.056. Five point six percent is still plutonium. Note that all of this material is contained in a hemisphere 1 km in radius, because of the leaching rates. The vast majority of the remaining material, as we have seen, remains within a few meters of the original contamination point.

Note that this is very consistent with what was found at Oklo. It is known that at Oklo, very little plutonium migrated more than a few meters over billions of years.

Note that like South Carolina, Oklo was a wet climate; for part of its history it was in a rain forest. Moreover the Oklo reactors formed in permeable sandstone, and still the plutonium did not move.

Yucca Mountain is not in a rain forest. I don't agree with placing plutonium in Yucca mountain. I think we should recycle it and fission it. But if it were placed in Yucca mountain, even if the mountain became a rain forest someday, it is very unlikely that any plutonium there would ever harm anyone.

Please, tell us all about it.

:rofl:

It is probably the case that anyone who didn't get the first time is incompetent to understand what I have written.

I have recently shown that I-129 is essentially non-hazardous, certainly not comparable to the cancer risk of say, burning wood.

Several interesting papers are readily available on the soil chemistry of ¹³⁷Cs and ⁹⁰Sr and I may reference them shortly.

It is very clear, in any case, that none of the risk associated with the existence of these isotopes is comparable to the risk of global climate change.

I note that a tremendous risk is represented by doing nothing. Doing nothing is typically punctuated by denial and fantasy, as in waiting for solar PV electricity to get around (in the next 50 years) to finally producing an exajoule.

They are biologically active and readily accumulate in human tissue.

"I-129 is essentially non-hazardous"

horseshit

http://www.health-physics.com/pt/re/healthphys/abstract.00004032-200503000-00005.htm;jsessionid=EkjFFPX7z6l2ddizrTNTOz7jGeHgnpa1HBjMtO9ZGo27R1IWP6Ya!-1070481199!-949856145!9001!-1

Abstract:
mdash;: Nodular formation of the thyroid tissue can occur as a result of exposure to radiation. The nodular goiter is a common disease seen in the city of Elazig and its surroundings, in the eastern part of Turkey. A prospective study was conducted in an effort to identify the role of 129I in drinking water supply. Specimens obtained from nodular and normal thyroid tissue during surgery and also water specimens were counted by nuclear spectrometric system. 129I radioactivity in nodular tissue was noted to be higher compared to normal tissue and the difference was statistically significant (p < 0.05). There was no statistically significant difference (p > 0.05) between 129I radioactivity in the water supply and tissue obtained from the patients who have malignant or benign nodular lesions. These results support that the 129I radioactivity level in the water supply is one of the risk factors of the nodular formation of the thyroid tissue in the eastern part of Turkey.

http://taylorandfrancis.metapress.com/(vdosni45i4n3tf55c0ks0v45)/app/home/contribution.asp?referrer=parent&backto=issue,2,13;journal,64,68;linkingpublicationresults,1:101944,1

and lots more...

negligible and on a global average, much lower, than the concentration of potassium-40 by a factor of many thousands.

As for this googled abstract: A specific report in the literature is not proof of anything, but the body of data, critically evaluated, is. Globally the distribution of I-129 is about 1 in three billion atoms of iodine. It may be shown by calculation that this concentration is essentially of zero risk. One can find similar reports to this one published by Sternglass all over the internet, usually referenced frequently at the vast circle jerk of anti-nuclear websites, but that doesn't make Sternglass right. Most serious people understand that he is out to lunch.

I note that I-129 is a pure beta emitter and has much lower decay energy than potassium-40. Since the concentration of iodine is smaller than potassium, and because the occurrence of iodine-129 is proportionately (even adjusted for half life) much smaller, the risk of I-129 is basically non-existent. The cancer dose probability of I-129 has been estimated, and is 1.15 X 10^-2 per gram. Since the content of human flesh is not on a gram scale, and because I-127 still far outweighs I-129 by a factor of billions, the risk is negliable.

In any case, the issue is not whether or not there is some incidence of injury from I-129, or any fission product resulting from the use of nuclear power. The question is whether on a risk normalized basis whether the risk is lower than all competing forms of energy. If it happens that I-129 kills one person out of every 10 million exposed to it for each megawatt of energy produced, and 6,000 people out of every 10 million die from the air pollution associated with burning wood for each megawatt, it makes a difference. By choosing wood over nuclear, one would be executing almost 6,000 people.

One of the more absurd pretensions of the irrational anti-nuclear movement is to pretend that nuclear energy must be risk free. This is nonsense. Among scalable forms of energy, including most renewables, nuclear energy is simply risk minimized with respect to all other forms of energy, as I have repeatedly shown on this website.

Again: There is no such thing as risk free energy. There is only risk minimized energy. That energy is nuclear energy.

Thyroid cancer is rare even in the Chernobyl area, and it is largely curable. Lung cancer associated with air pollution is not rare and it is generally not curable. It is very clear, of course, that the incidence of thyroid cancer is hundreds of times larger in the Chernobyl area than in other areas, but still we are talking about 100's of people. More people die in New York every year from air pollution than will die of thyroid cancer in the Chernobyl area.

The representation that Cs-137 is "highly mobile" is greatly over simplified and comes from the kind of thinking that reads googled abstracts. In fact the chemistry of Cs-137 (and Sr-90) is complex and depends very much on soil type and location.

It would be nice of Cs-137 were "highly mobile" since it would have washed out into the ocean a long time ago where the activity would be dwarfed by the 500 billion curies of potassium-40 now found in the ocean. However the mobility of Cs-isotopes is greatly affected by the presence of illitic clay minerals, as is well known by anyone who has seriously studied the issue. There are many places where Cs is essentially immobilized.

I would compare the facile statement that "Cs-137...are highly mobile fission products" with the commentary of scientists, for example, this statement:



The latter is from Environ. Sci. Technol. 1999, 33, 1218-1223, the former is from nowhere.

Moreover the biological availability half-life not only varies with soil type, but by the nature of the crops grown as well.

In any case, Chernobyl is the only fatal commercial nuclear accident involving release of the inventory of fission products. It was an accident in a type of reactor that was already rare and that will never be built again. I note that there is not one anti-nuclear activist who gives a shit about coal accidents, for instance, even though they vastly outstrip Chernobyl in effect and occur regularly.

I cannot get anyone to care as much about this story from a few weeks ago: http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=43122&mesg_id=43122.

Everybody makes a big deal about Chernobyl which happened 20 years ago, though. If people gave more of a shit about the first case, in my opinion the world would be a far better place, far more ethical.

But again, the matter comes down to risk minimization since risk elimination is clearly impossible. The conceit raised by ill informed nuclear opponents that nuclear energy must be perfect while any other form of energy can be used indiscrimately in spite of much greater risks is probably going to be fatal to humanity as a whole. That irrational notion is what I am fighting against. Nuclear energy is not zero risk. It is just safer than everything else. To rational minds, the conclusions to be drawn are clear.