Re: Commissioner Dicus speaks on the public's perception about Radiat ion Pro...

[glen.vickers@EXELONCORP.COM]

Group,



I think the point that the 10% smear efficiency value is not really used is

valid.  I don't know of anyone in commercial nuclear power that uses a 10%

smear efficiency for personal protection measurements (10CFR20).  For

example, all that I've seen in writing says that a GM frisker should be able

to see 1000 dpm on a smear.  Using a 100% smear efficiency, this is

approximately 100 cpm above bkg, but if you used a 10% smear efficiency,

you'd be looking for approximately 10 cpm above background.  Detecting 10

cpm above background by visually averaging a needle on a meter display

cannot be done accurately and consistently.  You would need to use a

"scaler" for all of your smears.  How about starting off with 20 dpm on an

alpha smear and following the same train of thought?...  In the shipping

world, the LSA/SCO NUREG is quite clear that NRC believes that a 10% smear

efficiency should be used for DOT (49 CFR) measurements.  I believe that

most still use 100% efficiency for these measurements still and will have to

find a way to shoehorn themselves within the guidance in the NUREG.



I believe this a reasonably accurate picture of where things stand now.  Any

comments or other views on the current state of things?



Glen Vickers

glen.vickers@exeloncorp.com



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

> From: tom_dixie [SMTP:tom_dixie@MSN.COM]

> Sent: Friday, March 30, 2001 4:26 PM

> To:   Redmond, Randy R. (RXQ) ; radsafe@list.vanderbilt.edu

> Cc:   'William R Horne/HRW/CC01/INEEL/US'; 'Scott Davidson'; 'Lavera, Ron'

> Subject:      Re: Smear Collection Efficiency

> 

> Randy,

> 

> Nice work, now that you have a basis (or perceived basis) for collection

> efficiency for activity on smears maybe something will be done with that.

> The 'rule of thumb' that you have identified is an unused rule.

> 

> For example, if it was used, a smear that collected an activity of say

> 20,000 dpm would indicate a surface activity of 20,000/.1 or 200,000 dpm

> over the area that the smear was rubbed.  However, it is recorded as

> 20,000

> dpm over that area (usually 100 square cm).

> 

> 10% is also what the Navy used when I first qualified as a rad tech.

> However, the 'loose surface activity' was never determined using this

> factor.  It is real and should be used, any idea why it isn't?

> 

> There was also some indication (back in the early 70's) that for larger

> areas the smear would be less effective in collection and for some

> surfaces,

> like concrete, the smear (paper) would disintegrate.  Or in some cases

> would

> become a medium for transfer of activity to clean areas from contaminated.

> 

> There are many caveats to the use of this collection efficiency.  The

> smear

> must remain whole, the pressure over the smear surface must be uniform,

> the

> surface activity must be reasonably homogenious, etc.

> 

> It is obvious that smears do not collect 100% of the activity on a surface

> (otherwise the surface would be clean) but the current method of surface

> activity determination simply leads people to believe that surfaces are

> cleaner than they are.

> 

> Tom O'Dou, CHP, RRPT

> tom_dixie@msn.com

> 

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

> From: "Redmond, Randy R. (RXQ) " <RXQ@Y12.doe.gov>

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

> Cc: "'William R Horne/HRW/CC01/INEEL/US'" <HRW@INEL.GOV>; "'Scott

> Davidson'"

> <bsdrp@YAHOO.COM>; "'Lavera, Ron'" <RLavera@ENTERGY.COM>

> Sent: Friday, March 30, 2001 12:19 PM

> Subject: Smear Collection Efficiency

> 

> 

> > Many thanks to those who responded to my inquiry.  10% for the smear

> > collection efficiency appears to be the "rule-of-thumb".  Found a report

> > (RADSAFE Archives) with some actual test data.

> >

> >

> >

> http://ww2.packardinst.com/packard/ecom/pcatalog.nsf/ec5d943f415be30285256

> 8c

> > 2005e6eb3/ff6d3af15d0faeb6852568c30062da4a?OpenDocument   - Test Data

> >

> >

> http://www.google.com/search?q=cache:romulus.ehs.uiuc.edu/cgi-bin/lwgate/R

> AD

> >

> SAFE/archives/radsafe9501/Subject/article-180.html+%22collection+efficienc

> y%

> > 22+and+swipe+OR+smear&hl=en

> >

> > www.epa.gov/radiation/marssim/docs/revision1/apph.pdf  - do a search for

> > "collection efficiency"

> >

> > Randy Redmond

> > BWXT Y-12 L.L.C.

> > Y-12 National Security Complex

> > Radiological Control Organization

> > Email:  rxq@Y12.doe.gov

> > Phone:  865-574-5640

> > Fax:  865-574-0117

> >

> > ************************************************************************

> > You are currently subscribed to the Radsafe mailing list. To

> unsubscribe,

> > send an e-mail to Majordomo@list.vanderbilt.edu  Put the text

> "unsubscribe

> > radsafe" (no quote marks) in the body of the e-mail, with no subject

> line.

> >

> 

> ************************************************************************

> You are currently subscribed to the Radsafe mailing list. To unsubscribe,

> send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

> radsafe" (no quote marks) in the body of the e-mail, with no subject line.





*********************************************************************************

This E-mail and any of its attachments may contain Exelon Corp. proprietary

information, which is privileged, confidential, or subject to copyright 

belonging to the  Exelon Corp. family of Companies.  This E-mail is intended

solely for the use of the individual or entity to which it is addressed.  If

you are not the intended recipient of this E-mail, you are hereby notified

that any dissemination, distribution, copying, or action taken in relation

to the contents of and attachments to this E-mail is strictly prohibited

and may be unlawful.  If you have received this E-mail in error, please

notify the sender immediately and permanently delete the original and

any copy of this E-mail and any printout.  Thank You.

*********************************************************************************

************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.



------------------------------