Steele Faucet wrote:He goes on to give a hypothesis, but admits that there are things he does not understand.
Here is Dr. Paul K. Kuroda's words, regarding the unexpected ratio of xenon 136 to xenon 134 (my emphasis):
Scientific American, The Workings of an Ancient Nuclear Reactor, 01/26/09, by Alex P. Meshik who wrote:Our understanding of the anomalous composition of the xenon came only after we thought harder about how this gas was born. None of the xenon isotopes we measured were the direct result of uranium fission. Rather they were the products of the decay of radioactive isotopes of iodine, which in turn were formed from radioactive tellurium and so forth, according to a well-known sequence of nuclear reactions that gives rise to stable xenon.
Our key insight was the realization that different xenon isotopes in our Oklo sample were created at different times— following a schedule that depended on the half-lives of their iodine parents and tellurium grandparents. The longer a particular radioactive precursor lives, the longer xenon formation from it is held off. For example, production of xenon 136 began at Oklo only about a minute after the onset of self-sustained fission. An hour later the next lighter stable isotope, xenon 134, appeared. Then, some days after the start of fission, xenon 132 and 131 came on the scene. Finally, after millions of years, and well after the nuclear chain reactions terminated, xenon 129 formed.
This appears, to me anyway, to be a statement of fact and not an hypothesis, whereas his hypothesis is an explanation of how a controlled chain reaction can occur in nature (which he later matches with the evidence of the site).
Toward the end of the article, he adds this possibility:
Scientific American, The Workings of an Ancient Nuclear Reactor, 01/26/09, by Alex P. Meshik who wrote:This picture of how the Oklo reactors probably worked highlights two important points: very likely they pulsed on and off in some fashion, and large quantities of water must have been moving through these rocks—enough to wash away some of the xenon precursors, tellurium and iodine, which are water-soluble. The presence of water also helps to explain why most of the xenon now resides in grains of aluminum phosphate rather than in the uranium rich minerals where fission first created these radioactive precursors. The xenon did not simply migrate from one set of preexisting minerals to another—it is unlikely that aluminum phosphate minerals were present before the Oklo reactors began operating. Instead those grains of aluminum phosphate probably formed in place through the action of the nuclear-heated water, once it had cooled to about 300 degrees Celsius.
It is not entirely obvious what forces kept this xenon inside the aluminum phosphate minerals for almost half the planet’s lifetime. In particular, why was the xenon generated during a given operational pulse not driven off during the next one? Presumably it became imprisoned in the cagelike structure of the aluminum phosphate minerals, which were able to hold on to the xenon gas created within them, even at high temperatures. The details remain fuzzy, but whatever the final answers are, one thing is clear: the capacity of aluminum phosphate for capturing xenon is truly amazing.
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Kuroda matches the evidence found at Oklo to his (self-sustaining chain-reaction) theory and IMHO does an excellent job:
* had to be at least 2 billion years old (because of half-life of U325)
* the deposit had to be a certain size and abundance
* a substance acting as a neutron “moderator" must be present, like water (which needs to boil away)
* the absence of certain element that would have prohibited the reaction
In the case of the Oklo site, these factors are all confirmed and the resultant yield-products are present, although the time factor involved did impact: the ratios found (determined), some of the types of isotopes present (explained), and how a few of those isotopes formed (speculative). Overall, a remarkable feat for Kuroda with the evidence supporting his theory and no evidence excluding it.
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Given that the first factor listed above is absolutely certain (Earth is over 4.4 billion years old) and the last couple of factors are quite common, and then it is perhaps a distinct possibility that appropriate circumstances might occur for a natural, self-sustaining chain-reaction to take place. Given that the empirical evidence does fit Kuroda's theory, then it is certainly reasonable.
The fact that 16 reactions occurred in the same area where the necessary conditions were present is testament that the circumstances in that area were of the correct nature. This is a reflection of the old saying, "most important numbers in science: 0, 1, and 2."
ZERO: means it does not exist
ONE: means it does exist
TWO: means if it exists more than once, then it can exist multiple times.
Now if these reactions occurred millions of years ago, or in several different geographical areas where the conditions were largely not conducive to a natural process, or if the reaction products contained unexplainable isotopes, then all bets are off, but given the evidence and circumstances (and lack of anything remotely indicative of an artificial reactor), this may not be the best AAT propositional stand. (of course, if a manual is found is some strange script at the correct strata level, entitled: "How to Operate the Nuclear Reactor...well, game on.")
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An
uncontrolled chain-reaction, that is a different matter, but I did not see any mention of this except in the Jeff Sheets thread about such a possibility occurring on Mars. Also,
is a natural, uncontrolled, fission chain-reaction possible (aka: an atomic explosion) and if is, how likely? If it turns out hat such an occurrence is unlikely, and if there was such an explosion on Mars: whoa. Even if the Mars reaction was controlled, if the requisite conditions were not present, then same thing: whoa. That is a theory that should be followed-up.
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One last thing, second to last paragraph he adds this tidbit:
"For three decades, the two-billion-year old Oklo phenomenon has been used to argue against [the fundamental physical constant known as
Alpha] having changed. But last year Steven K. Lamoreaux and Justin R. Torgerson of Los Alamos National Laboratory drew on Oklo to posit that this “constant” has, in fact, varied significantly (and, strangely enough, in the opposite sense from what others have recently proposed)."
Dude!
This is incredibly cool, just mentioned in passing!
by Jeff Sheets » Mon Apr 11, 2011 1:56 pm 
like they would even read it, let alone publish...
