Re: Yucca Mountain

[rkathren@tricity.wsu.edu (ron kathren)]

NCRP Report 121, recently issued, has specific guidance with respect to the
use of collective dose over long periods of time.  Specifically this report
cautions against the use of collective at long periods (eg 10,000 y) into
the future.  I suggest that this report be consulted.


Ron Kathren



>>Bob Flood wrote:
>>>
>>> >QUESTION: Is a time span of 10,000 years realistic?  Why should it be
>>> >designed to last for such a long and unforeseeable time period?
>>>
>>> I've heard it said, but I have never tried to verify by my own calculations,
>>> that a standard mix of spent fuel (mixed fission products) will decay to
>>> about the same total activity per unit volume as the original uranium ore in
>>> about 300 years. Has anyone done this calculation? If this is true, wouldn't
>>> it be reasonable to require protection only until the radioactivity levels
>>> are no worse than when they started?
>>>
>>> Bob Flood
>>> Unless otherwise noted, all opinions are mine alone.
>>> (415) 926-3793
>>> bflood@slac.stanford.edu
>>
>>We have recently performed performance assessments to support closure of
>>high level waste tanks at a DOE facility.  The
>>isotopes that contributed most of the potential dose through the
>>groungwater pathway during the 10,000 year period of
>>interest were Tc-99 and Se-76.  The NRC has also focused on I-129.  All of
>>these isotopes have very long halflives and remain
>>long after the 10,000 years considered.
>>
>>What I am interested in, due to their very low specific activity, is it
>>physically possible to consume sufficient quantities
>>of these materials to receive a significant dose?  Some years ago, I
>>performed back-of-the-envelope calculations for I-129
>>and came to the conclusion that it was not possible.  Does anyone have
>>references regarding this conclusion?
>some years ago Book, S.A. performed some research on I-129 and concluded
>that the specific activity question was such that iodine chemical poisoning
>would occir long before any radiation dose of significance; in the late
>'60's at UC Davis.  I think it is Health Physics or is an AEC report.
>
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