RE: Radioactive Walls

["Spell, Bill" <bills@deq.state.la.us>]

Do you suppose you may have been measuring the potassium-40 in the cement 
blocks?  When you moved the monitors to the center of the room, you still 
had the problem; you just didn't worry about it any longer, right?  Your 
assumption is probably correct.  Quarterly exchange is a viable alternative 
when you are measuring low exposure levels and don't pick up anything in a 
one-month reading, IMHO.

CULater......

 ----------
From: radsafe
To: Multiple recipients of list
Subject: Radioactive Walls
Date: Friday, June 07, 1996 1:13PM

Regarding Peter Vernigs Post:

        We had a similar experience here.  We decided to change our
monitoring period from monthly to quarterly.  When we did, we found that all
TLDs in one location showed ~10-15 millirem exposures (even the control
badge).

        Using a scintillation detector we found that the cement block walls
were slightly radioactive.  The TLDs were moved to a partition in the center
of the room and we haven't had a problem since.

        Evidently the threshold of the TLD was not exceeded during the
one-month monitoring period therefore zero doses were reported.
**************************** /^\   /^\ *********************************
Tad  Blanchard              /__ \ /___\    NASA-Goddard Space Flt Ctr
Nat'l Health Svc, Inc            O             Greenbelt, Maryland
Sr Health Physics Tech          / \            Phone: 301-286-9157
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                  Tad.M.Blanchard.1@GSFC.NASA.gov
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