[ RadSafe ] Fallout "preserved" in concrete

[Grant Nixon]

This is interesting. I would suspect that most of the radiation emanating from concrete would be due to naturally-occuring K-40. Any detection of Cs-137 (or rather, Ba-137m's 662 keV photons), however, would be wholly attributable to radioactive fallout itself. The Cs should chemically substitute for the Ca inside the concrete and form some lasting bonds.

Therefore, do you plan to use gamma ray spectroscopy (via a high-purity germanium detector) to identify particular radiation lines and count the peaks? Certainly, I would expect that any simple gross measurement of the overall exposure/dose rate from concrete would prove too variable on account of the variable levels of naturally-occuring K-40 to be found in concretes.

Best wishes,

Grant

Grant I. Nixon, Ph.D., P.Phys.
Senior Radiation Physicist
Best Theratronics
413 March Road
Ottawa, Ontario, Canada
K2K 0E4
________________________________________
From: radsafe-bounces at radlab.nl [radsafe-bounces at radlab.nl] On Behalf Of Keith Welch [welch at jlab.org]
Sent: Friday, February 20, 2009 4:33 PM
To: radsafe at radlab.nl
Subject: [ RadSafe ] Fallout "preserved" in concrete

Hello Radsafers,

I'm looking for data regarding levels of radioactivity in concrete as a
result of weapons fallout.  I'm evaluating some concrete that was cast
in the early to mid 1960s, and trying to determine if there might be
elevated levels of Sr-90 or other nuclides in the concrete due to the
prevailing levels in the environment at the time.  I've searched the
on-line literature pretty thoroughly, and have not come up with
anything.  Existing documentation that I can find only speaks to natural
radioactivity in concrete (NCRP etc.).
Thanks for anything you can suggest.
Keith Welch
Jefferson Lab
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