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Re: Iridium volatility
Private:
Franz Schoenhofer
Habicherg. 31/7
A-1160 Vienna, AUSTRIA
Phone: -43 699 11681319
e-mail: franz.schoenhofer@chello.at
Office:
MR Dr. Franz Schoenhofer
Federal Ministry for Agriculture, Forestry, Environment and Water Management
Dep. I/8U, Radiation Protection
Radetzkystr. 2
A-1031 Vienna, AUSTRIA
phone: +43-1-71100-4458
fax: +43-1-7122331
e-mail: franz.schoenhofer@bmu.gv.at
-----Ursprüngliche Nachricht-----
Von: Jacques.Read@eh.doe.gov <Jacques.Read@eh.doe.gov>
An: radsafe@list.vanderbilt.edu <radsafe@list.vanderbilt.edu>
Datum: Dienstag, 05. Februar 2002 22:29
Betreff: Iridium volatility
>
>
>Iridium carbonyl (carbon monoxide complex) sublimes at 250 degrees
Centigrade.
>
>Jacques
----------------------------------------------------------------
Having been on a committee of the Austrian Standardisation Institute dealing
with sealed sources and their testing for tightness I know very well, that
sealed radioactive sources are rigorously categorized and tested as to their
resistance to not only chemicals, but also to heat and mechanical forces. I
know as well, that the USA has standards for that and there are
international standards, because we tried to harmonize our standards with
international ones.
The question is not, at what temperature iridium vaporizes or melts, but
rather at what temperature and after what time the source will lose its
tightness and leak. The sources are clearly categorized as to what
conditions they will survive without leaking.
It is interesting, that iridium carbonyl will sublime at 250 centigrades -
but the stainless steel encasing must withstand the 250 degrees without
damage and so there will be no sublimisation even in a carbon monoxide
atmosphere!
Without knowing the type of the source and the circumstandes in terms of
temperature and possible mechanical force (which seem not to have been
present), it is not possible to make any judgement of that "incident". What
has been on RADSAFE hitherto is just speculations and in line with so-called
"whistle-blower activities". I could imagine that there are quite a few
RADSAFE members who know much more about such radioactive sources, than I
do. May I ask you for comment?
Franz
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