Re: A real solution

["Jerry Cohen" <jjcohen@prodigy.net>]

In case anyone is interested in the details of my previous posting on this
thread, the published report is:

Cohen, J et al, "Assessment of Issues Related to Determination of Time
periods Required for Isolation of High Level Waste", Proc. WASTE MANAGEMENT
'89, U. of Arizona,

jjcohen@prodigy.net


-----Original Message-----
From: Jerry Cohen <jjcohen@prodigy.net>
To: radsafe@romulus.ehs.uiuc.edu <radsafe@romulus.ehs.uiuc.edu>
Date: Friday, August 18, 2000 3:52 PM
Subject: Re: A real solution


>I believe I am the one who is responsible/guilty ( U pick) for  deriving
>sets of curves relating the ingestion radiotoxicity  and/or chemical
>toxicity of spent fuel as a function of decay time. This was part of a
>project for DOE and related to the Yucca Mountain project. It was intended
>to address the question of when a nuclear waste repository becomes less
>hazardous than a undisturbed uranium ore deposit.The study was done during
>the early 1980's. I found the curves in my old files and can summarize them
>as follows: [1] Using ICRP-2 data
>(I told you these were old), spent fuel (33,000 MWD burnup) does indeed
>become less toxic than uranium ore in ~300 yr, [2] using ICRP-30 data, it
>takes about 10,000 years, and [3] with ICRP-48 data it becomes more like
>~100,000years. Another interesting relationship that we calculated in this
>study assumed that at time zero we had 1.0 Kilogram of natural uranium and
>had a choice of either fissioning every atom to produce nuclear power, or
we
>could leave it alone let it decay "naturally". We followed the toxicity
>index of this one kilogram of material ,i.e. fission products vs natural
>decay products ( considering both radio and chem toxicity- the stable end
>product of natural decay being mostly toxic lead) and found a crossover at
>about one million years. In other words, if you wait long enough, the world
>becomes toxic as a result of nuclear power production. But who cares!
>
>
>-----Original Message-----
>From: Michael McNaughton <mcnaught@lanl.gov>
>To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
>Date: Friday, August 18, 2000 2:37 PM
>Subject: Re: A real solution
>
>
>>At 02:54 PM 8/18/00 -0500, you wrote:
>>>Some years ago I was told by someone whose opinions I respect that the
>>>oft-used 10,000 year worry period is way off and that spent fuel will
>decay
>>>to being no more radioactive than the original unirradiated fuel in about
>>>300 years.
>>
>>I have seen this presented as a graph, but with essentially no
>>justification, no references, and no technical details. The graph is
>>"ingestion toxicity" versus time; Pu is assigned a low ingestion toxicity
>>because it is insoluble. After almost 1000 years, the total ingestion
>>toxicity of the high-level waste from a LWR is shown as less than the
total
>>ingestion toxicity of the original uranium ore used to make that fuel.
Many
>>years ago I tried and failed to find the origin of the graph so I could
>>check the details.
>>
>>mike
>>
>>Mike McNaughton
>>email: mcnaught@LANL.gov or mcnaughton@LANL.gov
>>phone: (505)667-6130
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>

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