Re: How much Sr-90 in clip-on lights? -Reply

[avest@magnus.acs.ohio-state.edu (Albert Lee Vest)]

Remember this??

>Like the subject says.  We recently found five of these in a
>steel pig in a physics department lab.  Two are 1" diameter,
>three are 2" diameter.  All are in sheet-metal cases, painted
>black but deteriorating, and have the engravings "USRC" and
>"Poison Inside."
>
>[They don't say Sr-90, but the GM tells me it ain't tritium.]  In
>order to dispose of them, I need to know how much activity is
>probably contained in these items.

Someone suggested, contrary to my personal experience, that the lights
contained Radium instead of Sr-90:

>I suggest doing an MCA do be sure.  Paul's estimate of 5 uCi may be low for the
>larger ones which may have contained 10 -20 uCi.

Well that's what I did, and he was right!  Another victory of
open-mindedness over experience (prejudice).

All five of them appear to have the same activity, since they make a GM sing
as much.  A 'nuclear' 1-microCi check source makes ~20K cpm, and each of
these lights make ~200K cpm, so I'm going to say they each contain (duh!) 10
microCi.  Of Ra-226, of course.  Any dissenting opinions?

Thanks for all the suggestions and insight.

Albert Lee Vest           The Ohio State University
Health Physicist    Room 103 1314 Kinnear Road Bldg
(614)292-1284                     1314 Kinnear Road
avest@magnus.acs.ohio-state.edu   Columbus OH 43212
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