[ RadSafe ] U-236 in DU

Thu Jul 17 15:05:27 CDT 2008

Given that the process of uranium enrichment is the separation of
lighter isotopes of uranium from the heavier isotopes of uranium, I
would expect there to be less U-236 in DU because U-236 is
preferentially concentrated in the U-235 product stream and separated
from the U-238 which is, of course, what the DU is.

While it is true that there are some stores of uranium hexafluoride
available from when the US still practiced fuel reprocessing where the
concentration of U-236 is higher than natural, these stores are at
approximately natural enrichement and, as far as I can tell, wouldn't be
associated with DU.

So, based on my experience in the uranium enrichment industry, U-236 and
DU have nothing to do with each other.  If anything, the DU should have
less U-236 than natural U.

-Jason Bolling

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of Roger Helbig
Sent: Thursday, July 17, 2008 5:15 AM
To: Radsafe
Subject: [ RadSafe ] Analysis of Hawaiian Soil Sample for Depleted
Uranium

It is interesting that upsilquitch (believed to be Ted Weymann of the
so-called Uranium Medical Research Centre, with no known education or
experience in either uranium or medicine) belittles this report from
Professor Randall Parrish, who normally sides with the anti-depleted
uranium crusaders, such as his being invited to Colonie, NY to sample
the area around the closed National Lead Foundry FUSRAP site.  What do
you say about Parrishes presumption that U236 is indicative of depleted
uranium.

Roger Helbig

--- On Wed, 7/16/08, upsilquitch <upsilquitch at yahoo.com> wrote:

From: upsilquitch <upsilquitch at yahoo.com>
Subject: [DU-WATCH] Randy Parrish (MOD lap dog) lies to people fo
Hawaii, too
To: du-watch at yahoogroups.com
Date: Wednesday, July 16, 2008, 9:50 AM

Report on Uranium Isotope Analysis
For the attention of:
David Bigelow
8 July 2008
I apologise for any delay, but I am pleased to now provide you with a
uranium isotope analysis and concentration of the sample you submitted.
Conclusion in lay terms
The analysis of dust submitted contains a maximum of 1% Depleted Uranium
as a proportion of the total uranium in the sample. The uranium in the
dust is less than 1 part per million, a value that is typical for rocks
that would occur in Hawaii. The uranium contained in the dust sample is
overwhelmingly or entirely dominated by this natural uranium component.
Any DU, if present at all, is in fact less radioactive than the natural
uranium in the sample by virtue of its being `depleted' in the more
radioactive isotopes 234U and 235U. 
As such the radioactivity of the sample is virtually dominated by
natural background radioactivity, and any additional component if
present adds a negligible additional amount to this. In fact the normal
variation in amount of background radioactivity in rocks is far larger
than the maximum additional component, if any, of DU in the sample.
Technical aspects of the analysis
For your dust sample, the 4M HNO3 leach dissolved all but the silicate
portion of your samples and the ratio of 238U/235U was
138.92 with an uncertainty on the measurement of 1.01. The normal value
is 137.88. Your measurement with its uncertainty band can be argued to
be sufficiently close to the natural value as to conclude that it
contains no DU. On the other hand it is slightly elevated and given the
isotopic composition of depleted uranium munitions, a value of 138.9 is
also consistent with 1% of the uranium in the dust being DU and the rest
being natural. When DU makes a contribution to uranium, it also
contributes the rare isotope 236U. A 1% DU contribution would result in
a 236U/238U value of ~3.0 x 10-7. The value of this quantity we measured
in your sample was 5 x 10-7 but with an uncertainty of 5 x 10-7, in
other words this measurement is just at our detection limit. While both
measurements can be regarded as failing to prove the presence of DU they
are also consistent with a 1% DU contribution to the dust uranium which
is effectively the lowest contribution we can measure. The concentration
of uranium in the dissolved dust material is 0.68 parts per million,
which is quite normal for volcanic rocks like those that are common in
Hawaii.
Should you have any further questions, please do not hesitate to contact
me.
1
The methodology of the test is similar to that described in the
publications entitled :
Parrish, R. R., Arneson, J.Brewer, T., Chenery, S., Lloyd, N.,
Carpenter, D. 2008. Depleted uranium contamination by inhalation
exposure and its detection after >25 years: implications for health
assessment. Science of the Total Environment, Science of the Total
Environment v. 390, 58-68; doi:10.1016/j.scitotenv.2007.09.044. and
Parrish, RR, Thirlwall, M, Pickford, C, Horstwood, MSA, Gerdes, A.,
Anderson, J., and Coggan, D., 2006, Determination of 238U/235U,
236U/238U and uranium concentration in urine using SF-ICP-MS and MC-
ICP-MS: An interlaboratory comparison. Health Physics v.90 (2), p. 
127-138.
Or you can read of the procedure by visiting the method of Laboratory
`B' of the following website: 
http://www.duob.org.uk/laboratory.htm
Sincerely,
Professor Randall Parrish
NERC Isotope Geosciences Laboratory
British Geological Survey
rrp at nigl.nerc.ac.uk

_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood
the RadSafe rules. These can be found at:
http://radlab.nl/radsafe/radsaferules.html

For information on how to subscribe or unsubscribe and other settings
visit: http://radlab.nl/radsafe/