AW: A "dirty bomb" question

["Franz Schoenhofer" <franz.schoenhofer@CHELLO.AT>]

    -----Ursprüngliche Nachricht-----

    Von: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu]Im Auftrag von LNMolino@AOL.COM

    Gesendet: Samstag, 25. Oktober 2003 04:18

    An: radsafe@list.vanderbilt.edu

    Betreff: A "dirty bomb" question





    As most of you know I teach in a federally sponsored (DHS ODP) training

program for Weapons of Mass Destruction (WMD).



    I had a fellow instructor present me with a question that he could not

answer during our RAD/Nuclear module.



    How many elements from smoke detectors would it take to make an

"effective" dirty bomb?



    Note that as for effective we are speaking in terms of giving us

(response forces) a reading on a meter of greater than naturally occurring

background.



    Please remember that the answer we seek is not technical in nature nor

do we want the exact formula to build such a device just an answer that we

"lay" person instructors need to answer the question of a response oriented

student.



    ---------------------------------------------------------



    Louis,



    A very simple answer would be to cite a former collegue of mine and his

opinion about the hazard of smoke detectors: If you bite on one you might

damage your teeth.



    The Am-241 is contained in a ceramic matrix. Not being an expert on

explosives I would guess that it would need quite a violent explosion to

volatile or even "atomize" the ceramic matrix and the Am-241, so that

particles would be created which could enter the lung. Such a violent

explosion would kill because of the shockwave a lot of persons if detonated

in a crowded place - so you would not need to bother about the radiation

hazard. Am-241 is not really a highly radiotoxic radionuclide, so the small

amount reaching the alveoles might be of no concern.



    In one of the answers some estimations were brought forward. But the

conditions leading to these estimations were not given. The dose values

given seem to me much too high, probably the assumptions were total

volatilisation, fast absorption (which is not possible) and whatsoever to

give a worst case scenario. To calculate worst case scenarios is o.k., but

if these calculations even come close to dose limits, realistic calculations

have to be done. In the case of Am-241 in smoke detectors I assume that the

realistic doses are lower by order of magnitudes than caculated for a worst

case scenario.



    Best regards,



    Franz