[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: Determining activity of odd shaped parts

Couple of thoughts...

I believe NUREG-1608 for LSA/SCO would call your collection of small
activated materials such as yours LSA unless the materials are less than 2
nCi/g.  If the material is less than 2 nCi/g, then assess the contamination
levels on the material itself as SCO.  The NUREG is the best clarification
available.  Read it closely and I'm sure you'll have a few follow-up
questions to bounce off of other experienced shippers.

As far as actually characterizing the material, you can obtain a code for
money or perform hand calcs.  I believe some who came before me performed
hand calcs under the guidelines of an Edison Electric Institute document,
September 1978.

Put your small items in a good geometry such as a 55 gallon drum and record
exposure rates of the package for the dose-to-curie calculation.

For a total package, I would spend a little money for an industry standard
code package called, "Radman" by WMG (914-736-7100).  The program is well
accepted and essentially the industry standard in the power plant arena.

Is there a concern that your circuit boards contain any non-radiological
hazards which may complicate disposal?

Sincerely,
Glen Vickers
glen.vickers@ucm.com

	-----Original Message-----
	From:	Edwards, Richard W [SMTP:Richard.Edwards@PSS.Boeing.com]
	Sent:	Thursday, March 18, 1999 12:17 PM
	To:	Multiple recipients of list
	Subject:	RE: Determining activity of odd shaped parts

	Clarification:

	I should have expressed this as a two part question. 

	First, I need to come up with geometry corrections for odd part
shapes being analyzed by gamma spectroscopy (HPGe). Small parts can be
counted in a typical fixed system with a shielded cave. Larger parts could
be counted with a portable HPGe. Beyond that, we don't have a lot of
specialized equipment. Just the usual collection of portable contamination
detectors and dose rate meters.

	Second, our organization is trying to define the best method for us
to determine the activity of parts activated by exposure to our
accelerators. We are looking for suggestions from others.
	 
	Rick Edwards, Analyst
	The Boeing Company
	richard.w.edwards@boeing.com

	> ----------
	> From: 	Keith Welch[SMTP:welch@jlab.org]
	> Reply To: 	radsafe@romulus.ehs.uiuc.edu
	> Sent: 	Thursday, March 18, 1999 9:49 AM
	> To: 	Multiple recipients of list
	> Subject: 	Re: Determining activity of odd shaped parts
	> 
	> <HTML>
	> Richard,
	> 
	> <P>If you have access to a gamma spec system (and the parts are
small enough),
	> you can try counting them directly.&nbsp; You'll need to calibrate
a geometry
	> that minimizes to the extent practical the problem of the size and
shape
	> of the item.&nbsp; Or you can get one of the fancy in-situ
counting systems.&nbsp;
	> Sometimes we do this with small parts.&nbsp; If you have a point
calibration
	> source, you could try calibrating with the source at some known
distance
	> from the detector, then when counting, place the object at that
distance.&nbsp;
	> It will get you a fair estimate.&nbsp; In some materials (Al for
example)
	> you'll often have a lot of positron emitters that you can't ID and
therefore
	> can't estimate activity for because all you'll get is a big 511
peak.&nbsp;
	> But if you know what nuclides are present, you can estimate their
activity
	> by the count rate in that peak.&nbsp; But it sounded like you were
looking
	> for a way to calculate the induced activity rather than measure
it.&nbsp;
	> I'll pass your post along to our resident expert on that.&nbsp;
But often,
	> because of the assumptions you have to make when calculating this,
the
	> direct measurement method is probably just as good or better.
	> 
	> <P>--
	> <BR>Keith Welch
	> <BR>Thomas Jefferson National Accelerator Facility
	> <BR>Newport News VA
	> <BR>welch@jlab.org
	> <BR>Ph: (757)269-7212
	> <BR>FAX:(757)269-5048
	> <BR>&nbsp;</HTML>
	> 
	>
************************************************************************
	> The RADSAFE Frequently Asked Questions list, archives and
subscription
	> information can be accessed at
http://www.ehs.uiuc.edu/~rad/radsafe.html
	> 
	
************************************************************************
	The RADSAFE Frequently Asked Questions list, archives and
subscription
	information can be accessed at
http://www.ehs.uiuc.edu/~rad/radsafe.html
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html