Re[2]: List of materials containing naturally occurring nucl

["William CTR Kolb"<William.CTR.Kolb@faa.gov>]

     According to NUREG-1717, constant bombardment by high-energy electrons 
     eventually causes the glass in television faceplates to darken and 
     turn brown due to the creation of color centers in the glass atoms. 
     This effect can be reduced by adding approximately 0.3 percent cerium 
     oxide to the glass. Rare earth oxides such as cerium oxide, however, 
     usually contain throrium as a tramp contaminant. Assuming a typical 
     impurity of 0.25 percent thorium in cerium oxide, the specific 
     activity would be about 0.8 picocuries per gram of glass in the TV 
     faceplate. It is uncertain, however, if cerium oxide has been used in 
     video monitor faceplates.
     
     NUREG-1717 goes on to say that specialty automotive glass was designed 
     to block ultraviolet light and reduce solar heating by adding up to 
     1.5 percent cerium oxide. Such glass was widely used in luxury cars in 
     1988 and 1989 but usage has declined since then for economic reasons. 
     If the cerium oxide contained 0.25 percent thorium by weight, the 
     specific activity of those windshields would be about 4 picocuries per 
     gram.
     
     
     bill
     william.ctr.kolb@faa.gov
     
     
     


______________________________ Reply Separator _________________________________
Subject: RE: List of materials containing naturally occurring nuclide
Author:  <radsafe@romulus.ehs.uiuc.edu> at SMTPGate
Date:    04/11/2000 10:54 AM


     
     
I've read that there's NORM in the screen.
     
     
     
     
Antoine Philippe <pantoine@SCKCEN.BE> on 04/11/2000 11:45:57 AM
     
Please respond to radsafe@romulus.ehs.uiuc.edu
     
To:   Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu> 
cc:    (bcc: David P Harrison/BC2/AEPIN)
     
Subject:  RE: List of materials containing naturally occurring nuclides
     
     
     
     
Could someone said to me wat types of isotope are present in the computer 
monitors. What parts of the monitor are concerned (is it only the glass of 
the screen) ?
     
Philippe Antoine
Belgian Nuclear Research Center SCK?CEN 
Boeretang 200
B-2400 Mol Belgium
-----Original Message-----
From: dpharrison@aep.com [mailto:dpharrison@aep.com] 
Sent: lundi 10 avril 2000 11:56
To: Multiple recipients of list
Subject: Re: List of materials containing naturally occurring nuclides
     
     
     
     
Here is a list of items that I've received so far that may or that does 
contain
radioactive material to be mindful of before the material goes into the 
Restricted Area:
     
Computer or Video Monitors (naturally occurring radioactive material, NORM, 
in
the screen)
Breakers (arc chutes are made of materials that include NORM ~ 4k to 6k dpm) 
Cameras (some lenses and camera batteries contain NORM, Thorium coating on 
the
lens)
Welding rod (often contains NORM)
Batteries (may contain NORM)
Charcoal (contains Cs-137 as background) 
Grinding Discs
Timepieces (tritium, Promethium-147, Radium-226) 
Balances of Precision (tritium)
Marine compasses, self-luminous dials and instrumentation (tritium gas; 
Promethium-147; Kr-85)
Thermostat dials and pointers (tritium)
Electron tubes (tritium in the microwave receiver protector; Co-60; 
Nickel-63;
Krypton-85; Cesium-137; Promethium-147) 
Spark gap irradiators (Cobalt-60)
Synthetic plastic resins containing Scandium-46 which are designed for 
sand-consolidation in wells
Ice Detection Devices (Sr-90)
"Black Beauty" sandblasting grit
Rock wool (thorium) used for oven insulation and in fire doors
     
     
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