sealed source

["Les Slaback, Health Physics" <SLABACK@micf.nist.gov>]

The purpose of the DoT def of special form and manufacturer oriented
definitions of sealed source are to address essentially unknown but
presumed extreme conditions.  At a specific site, e.g., a specific license,
the purpose is to distinguish between to operations where contamination
might be unknowingly spread and hence need close surveillance, and those with s
ources that are adequately contained so that failure is easily recognized
and only infrequent, e.g., semi-annual, checks of containment are needed.
For this purpose my definition of a 'sealed source', is one that is
contained adequately for the approved usage.  This incorporates the factor
of the type of usage as well as the element of an approval process.
A glass vial used in lab calibrations could be a sealed source, but
certainly would not be approved for use in field operations where the
consequences of a failure would be more uncontrolled.

So, I do not believe there is a stand alone definition without defining the
circumstances in which this definition is to be used.  And applying
definitions like special form or those for high activity therapy sources
are inappropriate for defining surveillance programs for many licensee
activities, which is the underlying purpose of that definition in many
cases.

SLABACK@MICF.NIST.GOV
   ...a little risk, like a bit of spice, adds flavor to life