Date: Mon, 22 Feb 2010 08:49:51 -0700
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From: Frank Demer <demer**At_Symbol_Here**EMAIL.ARIZONA.EDU>
Subject: Re: Thorium Radiation in Tungsten Rods
In-Reply-To: <531227.26347.qm**At_Symbol_Here**>



-Frank Demer

From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of Craig Calvert
Sent: Monday, February 22, 2010 8:07 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Thorium Radiation in Tungsten Rods

Hello All,


I'm looking for some advice on proceeding with a site that used Tungsten Rods with 1-2% Thorium in welding.  The question I have is would a site that has used these be safe, or is the material "dangerous enough" to warrant a full radiological scan.  Details are given below:


One of the welding processes used at the facility used tungsten inert-gas (TIG) arc welding.  The tungsten rods used in the process contained 1-2% Thorium Oxide (aka as thoriated tungsten), which is radioactive.  The rods themselves are specifically except from NRC  regulations (classified as unimportant quantities of source material), however there was waste (dust) created by the process.  Dust from grinding and fumes from welding likely deposited on surfaces and would likely have been periodically  swept out of the facility or washed out and discharged to the surface impoundment.  There may also be residual dust inside the building.  If the welding process was vented, the gas and dust would have been discharged into the air and then deposited on the ground.  


Craig Calvert

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