[ RadSafe ] distinguishing fuel from non-fuel debris

BRONSON Frazier (CANBERRA) frazier.bronson at canberra.com
Mon Sep 27 12:35:57 CDT 2010

John:  Several years ago Framatome [now AREVA] had a contract with Maine
Yankee to reduce the volume of GTCC waste from all the random junk that
was in the spent fuel pool after the plant was shut down.  We built for
them an underwater ISOCS system [waterproof Ge detector with multiple
collimators].  They used it to identify the location of radioactivity,
the nuclides causing the doserate, and the activity.  All measurements
were done underwater [very interesting spectra !].  Several objects were
found that were labeled indicating that they were fuel fragments, but
ended up clearly being very high levels of Co60 which removed it from
the GTCC category.  This seems like your situation.

Perhaps they still do that service.  

Frazier Bronson CHP

Message: 5
Date: Mon, 27 Sep 2010 12:36:43 -0400
From: "Rich, John" <John.Rich at fpl.com>
Subject: [ RadSafe ] distinguishing fuel form non-fuel debris
To: "'The International Radiation Protection (Health Physics)
	MailingList'"	<radsafe at health.phys.iit.edu>
<4280D416A1C37D4CBB3B910ABEF2D4291B5508A745 at JBXEXVS04.fplu.fpl.com>
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Radsafers, we have a cleanup question.

We have a mixture of very old debris on the spent fuel pool floor.  It's
pretty much all the same color, and pretty much visually
indistinguishable as to its original source.  As you can imagine dose
rates vary all over the map.  The problem is distinguishing fuel from

It's not practical to run small quantities through an MCI, so I'm
looking for help on making a reasonable distinction.  The original
assumption was that if the dose rate is low it's not fuel.  But if the
dose rate is comparatively high, then it could be a fuel fragment, or a
Co-60 fragment, or some such.  We've considered analyses that take
radiodecay and sample size into account to develop a baseline.  (Haven't
performed the analyses yet, though.)

I'd appreciate some feedback on this.  Thanx in advance  - - jmr

John Rich
772-467-7000 #4103

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