Re: Puzzler

["Jack Topper"<jdtopper@icnpharm.com>]

Bates,

Are all of the metal components by chance galvanized or otherwise plated?
Not that I know very much about the process, but it seems plausible that
such a process would result in small quantities of NORM becoming plated
onto the surface of the material.

Jack Topper
ICN Dosimetry Services
jdtopper@icnpharm.com





Bates.Estabrooks@rfets.gov on 10/29/97 08:26:12 AM

Please respond to radsafe@romulus.ehs.uiuc.edu

To:   radsafe@romulus.ehs.uiuc.edu
cc:    (bcc: Jack Topper/HQ/ICN)
Subject:  Puzzler




          Here's a "Puzzler" for the RADSAFE community.  Unlike Click
          and Clack I don't know the answer, nor can I offer fuzzy dice
          to the winner, but this may be of interest to all of you and
          help us out a bit.
          Here at Rocky Flats we have a long history of working with
          "the most dangerous substance known to man."  As such, as we
          tear this place down, we need to screen everything that leaves
          the site for disposal, for "DOE radionuclides"; i.e.,
          239/240Pu, 241Am, 233/234U, 235U, and 238U.
          Recently we have surveyed several metallic items like trailer
          roofs, and chain link fence posts, using smears, and direct
          surveys with NE Electra instruments.  Often we have seen
          effectively no removeable activity (<20 dpm/100 cm2 alpha) but
          high direct alpha readings (~200 to 240 dpm/100cm2).
          Subsequently, we have covered these high spots with plastic
          and resurveyed days later to allow the short-lived activity to
          decay away.  In one case, with chain link fence posts, we
          covered eight spots, and allowed them to sit for 28 days (I'm
          not sure why that particular duration).
          The resultant surveys showed direct alpha activity still
          running in the range of 60-150 dpm/100cm2.
          In another similar instance (a trailer roof) we had a piece of
          the metal lab analyzed by radiochem. and alpha spec. for DOE
          nuclides and they all came back extremely low (Am: 0.0427
          pCi/g, Pu: 0.0177 pCi/g, 234U: 0.0338, and 235U: 0.0216).  We
          are having the fence posts analyzed now.
          So, the question:  what alpha-emitters are we seeing? And,
          what mechanism is fixing them to these metal surface so they
          are not seen on smears?
          Any ideas would be appreciated to help corraborate/refute our
          own.
          Bates Estabrooks
          RFETS
          bates.estabrooks@rfets.gov