Re: resuspension factors

["High Plains Drifter" <magna1@jps.net>]

BRZ, grinding, machining, and welding do not "re-suspend" contaminated

material.  Dispersion of contaminants during welding and grinding are due to

the physical forces imparted on the contaminants by the process being used.

Most are carried by the materials removed/expelled by the process.  Having

worked around welding, machining, and grinding operations, and viewed areas

after several years of operations, it is clear that most material plate out

on any surface (vertical and horizontal) close  to the operation (10-25 foot

radius in all directions).  Most grinding operations created particles of

varying size but most are non-respirable.  Machining, except for skim

cutting and polishing, generally produce heavy shavings that deposit close

to the machine, and are also normally covered in cutting oil.  The cutting

oil also binds the contaminations to the metal when heated during machining

operations, some is carried away by the fumes but is of minor significance.

Welding of a metal with fixed surface contamination (I assume that removable

contaminants will be removed before starting the process) will cause

airborne contamination, but is easily controlled local ventilation.  Plasma

or acetylene cutting of contamination metal creates more airborne

contamination that the other operations due to the large area of heat

application and vaporization of the surface materials.  Any operation that

would disperse contaminants during a process should be evaluated for the use

of containments and ventilation to control the spread of contaminants.



I once reviewed the controls and results of plasma cutting of old spent fuel

pool components.  I was amazed at the low spread of contaminants during the

process.  The components were hydrolazed prior to cutting.



H. Dean Chaney, CHP

URS Corp. Sacramento, CA

(916) 679-2086



"In science there is only physics; everything else is stamp collecting."

                                      --Ernest Rutherford



----- Original Message -----

From: "Thomas E. Potter" <pottert@erols.com>

To: "RADSAFE" <radsafe@list.vanderbilt.edu>

Sent: Friday, November 29, 2002 6:59 AM

Subject: RE: resuspension factors





> Virtually all of the resuspension factor work I have seen, including

> NUREG-1720 mentioned by Eric Ablequist, applies to resuspension of

> material deposited on floors, soils, or similar surfaces due to typical

> mechanical forces--floor traffic, wind, etc.  I seriously doubt that

> they would be directly applicable to grinding or machining operations

> such as those of interest to John Priest.  I suspect that use of

> conventional resuspension factors for those applications would greatly

> underestimate the airborne radioactive material concentration.

> Unfortunately, I have no alternate information sources to propose.

> There may be some empirical information available in the health physics

> literature, but I am unaware of any.  There may also be some industrial

> hygiene information relating dust load in air due to grinding

> operations.  That might be useful if one can estimate the average

> radioactive material concentration in grindings.

>

> Original post:

> Date: Wed, 27 Nov 2002 08:22:59 -0500

> From: "Abelquist, Eric" <AbelquiE@ORAU.GOV>

> Subject: RE: resuspension factors

>

> A terrific reference on the subject of resuspension factors was just

> published by the U.S. Nuclear Regulatory Commission: NUREG-1720

>

> "Re-evaluation of the Indoor Resuspension Factor for the Screening

> Analysis of the Building Occupancy Scenario for NRC's License

> Termination Rule", NUREG-1720; June 2002.

>

> This NUREG provides an excellent review of past literature concerning

> resuspension studies and culminates with a recommendation to use 1E-6

> m-1. You can find it electronically on the following web page:

>

> http://www.orau.gov/ddsc/dose/guidance.htm

>

> Regards

> Eric

>

> - -----Original Message-----

> From: John M Priest Jr [mailto:priestj@DTEENERGY.COM]

> Sent: Tuesday, November 26, 2002 3:45 PM

> To: radsafe@list.vanderbilt.edu

> Subject: resuspension factors

>

>

> Im looking for some input.

>

> From: brzibung@firstenergycorp.com

> To: John M Priest Jr <priestj@dteenergy.com>

>

>

> Jack:

>

> Would you have knowledge of or know of an electronic reference that

> could provide me with resuspension factors for machining on a lathe -

> perhaps surface grinding??

>

> I am working on a lesson plan that will help the techs estimate the

> amount of radioactivity that could be available to become airborne if,

> for example, fixed radioactivity was propelled into the air from a

> machining operation.  I am using values of E-5 per meter to E-7 per

> meter. There is an OE that discusses the machining of a valve stem that

> has a stellite seat with fixed and loose contamination of 7.8E8 dpm/100

> sq.cm. Consider the airborne activity if you use a resuspension factor

> of E-5 per meter.

>

> brz

>

>

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