Re: Japanese nuclear accident: Did the reaction oscillate?

["Bjorn Cedervall" <bcradsafers@hotmail.com>]

>Do not forget the natural phenomena in South Africa.
>That reactor has been around for a while and as far as I know, it is still 
>sustaining fission.

I thought about that but going backwards 1700 million years which I think 
was when the OKLO phenomenon (but that is not South Africa - you may refer 
to something I am not aware about) was taken place wouldn't put us at a 
U-235 enrichment level of almost 19 %. (Without correcting for U-238, 700 
million years back -> approx. 1.4% and then another 700 million years 
-approx. 2.8% U-235. We should land somewhere around 3.5% U-235 (I don't 
have time to do the calculations must rush in 10 minutes) 1700 million years 
ago (Rosalee Bertell writes 1700 years in her book BTW...). And then it 
turned itself off after 100 000 years or something like that - leaving the 
local sites with a depletion of U-235 plus some fission products/nuclear 
waste.

Thanks also to everyone responding to oscillation issue: It was as I assumed 
- a steady state thing - I wonder if this should be considered "fortunate" 
or not - a more intense initial reaction would probably have turned itself 
off by bursting the vessel or spilling out the uranium slurry ("nitrate 
mix") but that would have resulted in higher doses I suppose. With a high 
enrichment level it seems like (=my "gut feeling") the chance for steady 
state should be lower.

My personal thoughts only,

Bjorn Cedervall  bcradsafers@hotmail.com

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