🚀 go-pugleaf

In article <1992Aug24.185340.19127@unlinfo.unl.edu> cbettis@unlinfo.unl.edu (clifford bettis) writes:
>These small amounts are "exempt" quantities as 
>defined by the NRC. Comparable sources can be found in smoke 
>detectors, lantern mantels and even salt substitute. As far as 
>disposal goes, it used to be the case that smoke detectors were to be 
>returned to the manufacturer at the end of their useful lives; the NRC
>no longer requires this and I suspect it is the same for the bulbs. 

	Most smoke detectors use curium, and tend to have a much longer
"useful life" as a result.  The half life on Promethium is about 2 1/2
years, which is apparently the manufacturers approach to planned obsolecene
(can't have the light bulbs lasting forever!).  The gammas being put off
are fairly infrequent (< 1 per sec).

	The other interesting this is: not only are these bulbs limited to
a maximum useful life of ~2 years by the half life, the clock ticks on
regardless of whether you buy the things or not.  That means the life of
the bulb is limite to ~2 years > (shelf time + installed time), whereas
regular bulbs are (x hours) > (installed time).  Makes you wonder about
"sell by" dates and "close out" 'sales'.


					Terry Lambert
					terry_lambert@gateway.novell.com
					terry@icarus.weber.edu

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Disclaimer:  Any opinions in this posting are my own and not those of
my present or previous employers.