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RE: Deadly Plutonium ?
The question here is really "where does DU come from?" And the answer of
course is "the enrichment process." So if one is only feeding natural
uranium to the process, the DU will theoretically contain Pu, but probably
not in measurable quantities.
If a feed stream to the enrichment facility is reactor fuel, the DU will
contain measurable Pu. The point is that not all DU is created equally.
John Hamrick
Manager HS&E
Umetco Minerals Corp.
970-256-8820
> ----------
> From: Bradshaw, Keith[SMTP:Keith.Bradshaw@nnc.co.uk]
> Reply To: radsafe@romulus.ehs.uiuc.edu
> Sent: Thursday, February 10, 2000 7:20 AM
> To: Multiple recipients of list
> 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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