basis for I-125 contamination levels

["Moroney, Roger W" <WRMoroe@MKG.com>]

I was asked about why the contamination limit for I-125 was so low
during a decommissioning several years ago (while employed elsewhere). I
am a little hazy on the exact document titles but here goes.
Reg guide 1.86 references several documents one of which was, I believe,
an old ANSI standard. In the ANSI (??) standard, the surface
contamination limits were determined for various isotopes from several
factors including volatility, half life, radiation type and energy and
some creative hand waving. This resulted in an empirically determined
contamination limit. The nuclides were then divided into the two
categories. The derived I-125 limit happened to be very close to the
dividing line and, after rounding, ended up in the more restrictive
group.
I apologize for all the vagueness. I thought I still had copies of the
documents but I can not locate them. Perhaps someone could locate the
reference.
Roger Moroney
Radiation Specialist
Technical Director - External Dosimetry Program
Mallinckrodt Nuclear Medicine
wrmoroe@mkg.com
314.770.7457 voice & 7998 fax