Fwd: Re: Source Stuck - Ideas Requested

[James Barnes <james.g.barnes@att.net>]

Let's try that again.  The email burped.

Jim Barnes


Date: Tue, 20 Jun 2000 12:33:46 -0700
To: radsafe@romulus.ehs.uiuc.edu
From: James Barnes <james.g.barnes@att.net>
Subject: Re: Source Stuck - Ideas Requested

Paul,

Going by your description, it seems that the lead plug sitting on top of the 
source was once tapped, and has now stripped the "female" threads.  If so, 
then the plug should have a bolt hole facing toward the top of the pig.  I 
am assuming that the plug is loose in the hole and could be fairly easily 
lifted if you could get a grip on it.

If that's the case, you might try using an expansion plug.  The one I am 
thinking of has a rubber assembly that is expanded by pulling up on a rod or 
ring that compresses the rubber assembly which then jams into the side of a 
bolt hole or plug with enough force that it locks into place.  You might be 
able to lift the plug by running the plug into the hole, then expanding it, 
then lifting the plug out of the pig.  I believe these plugs are farily 
common around a plant, as they are commonly used to keep debris out of open 
pipe and tubing ends being weld prepped.  You might want to check with your 
QA or welding folks to see if they have any that would work.

Similarly, you could use one of the lead expansion taps that are used for
bolting stuff into concrete.  The principle is the same.

If the plug is not tapped, then you might try obtaining a radiograph of the 
source.  This would permit you to get a good idea of how deeply you could 
tap the plug in order to lift it out, and would tell you exactly where the 
source is located in relation to everything else in the pig.  Then you'd be 
able to tap some screws (and perhaps a manipulating handle of some type) 
into the plug and lift it out with a good feel for where the best position 
for them might be.


Jim Barnes, CHP
Radiation Safety Officer
Rocketdyne/Boeing
james.g.barnes@boeing.com


At 01:24 PM 6/20/00 -0500, you wrote:
>Greetings Radsafers:
>
>I currently have a 87 uCi Cs-137 source in a lead pig with an opening of
>0.75 inches.  The source is in the bottom of the Pig in it's normal
>location. The delimma is that there is a lead plug of unknown thickness
>above the source.  The air gap between the top of the plug and the top of
>the Pig is 1.5 inches.  The Pig is 6 inches tall.  Best guess is that the
>source is 3 inches from the top of the Pig and the plug over it.  We are
>trying to remove the plug, which has already been galled.  Our concern is to
>tap the lead plug to remove it without getting into the source itself.  I
>figure to try and roughly calculate the thickness of the lead plug.  The
>dose rate at the opening in the top of the pig is 0.7mrem/hr.
> Calculator is at home. - Thanks. - Paul.
>
>Paul B. Pollan, RRPT
>pbpollan@southernco.com
>
>
>
>************************************************************************
>The RADSAFE Frequently Asked Questions list, archives and subscription
>information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html

************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html