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Durabilty of sealed radioactive samples

  1. Aug 3, 2009 #1
    Hello everyone,

    Having recently been engaged in a laboratory class involving the measurement of the activity of various sealed radioactive samples, I am curious to know how durable these 'sealed' disks are...

    My question is, how long does it take for its 'sealed' state to become diminished through regular contact with steel forceps (moving the samples to Geiger counter) and pose a danger - i.e. spreading radioactive material around workspace area to unprotected students?
  2. jcsd
  3. Aug 3, 2009 #2


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    I don't know all of the rules, but usually a radioactive source is given to a laboratory for use during a specified time, which is normally such that the confinement is guaranteed. You have a certain licence time for using the source. Sources are also regularly inspected for damage.
    For instance, we use Am-Be neutron sources which have a confinement lifetime of 10 years. After 10 years, they have to be handed in and they will or be considered as waste and handled as such, or will be re-sealed. They are also inspected every year to see if no mechanical damage is done to the source. Also, normally every person which is endorsed to use the source has had a training which tells him/her what to do in case he has an accident with the source which might potentially damage it (like dropping it accidentally), or when he/she notices something strange with the source. In fact, the thing to do is to seal the area as quickly as possible, to call in radiation protection, and to test everybody who might have been near the area for contamination.

    I suppose that this depends on the strength and kind of source, also.
  4. Aug 3, 2009 #3


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    What kind of source? Most sealed sources are actually quite weak -- the Cs sources we use for calibration, for example, or even most Th/U/Pu disks. Obviously there are exceptions -- Am-Be neutron sources can be scary (we have several here).
  5. Aug 5, 2009 #4
    Thanks to vanesch and CRGreathouse.

    The sources were Am243, Sr90, Co60 and Cs137.
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