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Re: Deadly Plutonium ?
Pu got into uranium compounds processed at Paducah because (as I understand
it) those uranium compounds came from the Pu extraction and purification
processes at Hanford, and so would naturally contain small amounts of Pu
(and Np dnd, I imagine, Cm and Am) because no separation process is perfect.
Pu is not usually found in natural uranium.
Ruth F. Weiner, Ph. D.
7336 Lew Wallace NE
Albuquerque, NM
505-856-5011
fax 505-856-5564
ruth_weiner@msn.com
-----Original Message-----
From: Bradshaw, Keith <Keith.Bradshaw@nnc.co.uk>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Date: Thursday, February 10, 2000 7:19 AM
Subject: RE: Deadly Plutonium ?
>
>> Please, how does Pu get into DU? Are the enrichment plants contaminated
>> with
>> Pu? It seems so from all the current media articles on Paducah. If so,
>> what is
>> the measured Pu concentration in DU? Or has no one ever asked that
>> question?
>>
> Well, I did, on this very list about a year ago:)
>
> At the time it generated some conflicting postings and some
>interesting private emails. Some people were adamant that no Pu could ever
>get into DU, whereas others said it could be present. Several
correspondents
>suggested I must be mentally deficient for even asking the question.
>However, very recently Rodney Bauman provided the following to RADSAFE:
>
> <SNIP>
>Standards in existence since the early 1950s
>limited Pu-239 activity to approximately 10 ppb of uranium. This
>specification
>had to be met prior to reduction of the uranium in solution to solid UO3 at
>the
>reprocessing site. Most data show levels to be much less than this limit.
>For
>"natural" UO3 (i.e., approx. 0.71% U-235 by weight), 10 ppb equates to just
>over
>10% additional inhalation burden (using current 10CFR835 DAC values).
>
>Certain processes at the gaseous diffusion plant sites concentrated the
>transuranic content into "waste" streams. The most obvious is the fly ash
>produced during the fluorination of UF4 to UF6 in the GDPs' feed plants.
><SNIP>
>
>Now, some of the private mail I got at the time suggested that,
>historically, most wastes ended up in the DU stream precisely because that
>was seen as the 'waste stream'. Possibly this included the fly ash?
>
>Another RADSAFER (P Egidi) tells us the following:
>
><SNIP>
>One thing I haven't heard mentioned anywhere is that the "DOE Manual of
>Good Practices for Uranium Facilities", EGG-2530, June 1988, clearly states
>that these contaminants are a possibility. Page 2-5:
>
>"Much of the uranium feed material that is currently handled at DOE
>facilities has been reclaimed, or recycled, from reprocessed, spent reactor
>fuel. The chemical processes by which recycled uranium is purified leave
>trace amounts of transuranic elements (neptunium and plutonium) and fission
>products (mainly Tc-99). Recycled uranium also contains trace amounts of
>uranium isotopes not found in nature, such as U-236. At the concentrations
>in uranium from fuel reprocessing facilities, the radiological impact of
>these impurities is negligible in many cases. However, there are many
>routine chemical processes which tend to concentrate these impurities
>either in the uranium product or in reaction by-products such that
>radiological controls and effluent/environmental monitoring programs must
>consider these impurities in some cases."
>
>This manual was written by staff from Fernald, Rocky Flats, Livermore, PNL,
>and Portsmouth, and published by EG&G Idaho at INEEL.
>
>Clearly, it was known over 10 years ago in the DOE complex, and mentioned
>in this fairly widely-distributed manual. The paragraph to me seems to
>downplay the issue, but admits that it is there.
><SNIP>
>
>
>> Or is the DU used in weapons all from non Pu contaminated DU? Al
>> Tschaeche
>> antatnsu@pacbell.net
>>
> Perhaps someone will tell us!! I suppose the US has been using the
>'once through' fuel option since 1977, so since then, US DU should have
been
>made from virgin U, and hence relatively uncontaminated. That's as long as
>they haven't shipped in used U for re-enrichment from other countries. I
>don't know who in the world makes DU munitions and where they get their DU
>from. If it's sourced from countries like the UK, France or the old Soviet
>Union, which recycle uranium, there must be at least the possibility of Pu,
>U-236 etc in the DU. Also we don't know what, if any, standards (eg the
>10ppb limit for Pu mentioned above in the US - does that apply to DU?)
there
>are in these countries.
>
> Al, just asking this question seems to get some people upset. I'd
>like to emphasise that I've no particular axe to grind and I originally
made
>this enquiry for reasons entirely unconnected with Gulf War Syndrome etc.
>
> Just a humble seeker of the truth
>
> keith.bradshaw@nnc.co.uk
>
>
>> "Bradshaw, Keith" wrote:
>>
>> > When you take into account the dose coefficients for INHALATION
>> of
>> > insoluble species and for members of the public, by my reckoning it
>> takes
>> > only approx. 1ppm by mass of Pu-239 in DU to double its overall Sv/Bq
>> rating
>> > and hence reduce its DAC by a factor of 2. The presence of 238 and
>> 240-Pu
>> > (which is usual in civil Pu) would give a figure below 1ppm because of
>> their
>> > greater alpha activity per unit mass.
>> >
>> > Nat-U has about 1.7 times the U alpha activity of DU (of Rand
>> Report
>> > isotopic composition) so about 1.7ppm of Pu-239 in nat-U would
>> approximately
>> > double the radiological hazard weight for weight.
>> >
>> >
>>
>> begin:vcard
>> n:Tschaeche;Al
>> x-mozilla-html:FALSE
>> org:Nuclear Standards Unlimited
>> version:2.1
>> email;internet:antatnsu@postoffice.pacbell.net
>> title:CEO
>> x-mozilla-cpt:;0
>> fn:Al Tschaeche
>> end:vcard
>>
>>
>>
>>
>>
>>
>>
> END
>
>
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