Re: Use of Bag Monitors for 'Free' Release

["Frederick P. Straccia" <stracfp@naesco.com>]

     Larry,
     
     I'm involved in evaluating, calibrating, and operating instruments for 
     free-release of material at Seabrook Station in New Hampshire.  We 
     have been using an NE Technology bag monitor as part of a 
     green-is-clean program for evaluation of "clean" waste generated in 
     our RCA.  
     
     We had attempted to use the bag monitor as the primary instrument for 
     free-release, but met with resistance from our Regional Inspector.  
     While the bag monitor is much more effective than a frisker for 
     locating small amounts of contamination, the problem was the MDA.  In 
     a background of 25 uR/hr, the MDA is about 11,000 dpm (assuming our 
     DAW isotopic mix).  Our inspector then argued that a 5,000 dpm smear 
     located in the center of a bag would not be detected.  Even though a 
     5000 dpm smear has a good chance of being missed during a direct frisk 
     with a pancake GM tube, that's the industry standard, and that's what 
     we rely on in our program.
     
     For trash, each bag gets a check with a uR meter (has to be less than 
     25 uR/hr), then a check in the bag monitor (set to alarm at 15,000 
     dpm), then hand-frisking every item in the bag with a frisker or NE 
     CM-7, then shred the material, then count the bagged shredded material 
     in the bag monitor again.  
     
     While this may seem like overkill, it is acceptable by the Region I 
     folks, so that's what we do.  Give me a call if you have any 
     questions.
     
     Fred Straccia
     (603) 474-9521 X-3791
     (stracfp@naesco.com)
     


______________________________ Reply Separator _________________________________
Subject: Use of Bag Monitors for 'Free' Release
Author:  radsafe@romulus.ehs.uiuc.edu at Internet
Date:    5/2/96 10:40 AM


We are starting to evaluate the usefulness of a 'Bag Monitor' for 
free-releasing 'clean' trash from radiologically controlled areas.
I am interested in what the RADSAFE view is on this subject, specifically:
 - is anyone using these types of monitors now?
 - is there a problem using such a system for free release 
 - what types are available, who makes them, any advice
 - what administrative controls, limits or restrictions apply...
     
Thank you in advance for your assistance.
     
Larry Dauer
idauerl@ip3gate.usa.com
     
Radiological Engineering
IP3 NPP
P.O. Box 215
Buchanan, NY  10511
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