Re: values for exemption of sealed Radioactive sources

[kg1@cosmail1.ctd.ornl.gov (Kurt Geber)]

At 10:23 AM 7/2/96 -0500, Kathleen McIntyre wrote:
>Does ANYONE know how the exemption values for sealed sources were derived
>for DOE N 441.1, Attachment 1?  What is the technical basis for the values?!?
>
>We're trying to construct a table to list isoptopes not specified in the
>attachment...unfortunately, our numbers don't jive when comparing our
>calculated values to those of 441.1
>
>
>Thanks in advance,
>
>Kathleen McIntyre
>Brookhaven Nat'l Lab
>129B 
>Upton, NY 11973-5000
>
>516-344-5868
>
>
>mcintyre@bnl.gov
>

Kathleen,

The Implementation Guide, IMPLEMENTATION GUIDE For OCCUPATIONAL RADIATION
PROTECTION, SEALED RADIOACTIVE SOURCE ACCOUNTABILITY and CONTROL, US DOE,
G-N 5400.9/M1-Rev.1
NOVEMBER 1994, is on the Web at:
http://www.tis.eh.doe.gov/docs/ig/100224.txt.  It is based on "Source
Inventory Limits", George Kerr and Keith Eckerman, Health Physics Journal
Vol 59, No. 6 December 1990.  

Here is the applicable excerpt from the IG-
"Values in Appendix B for exemption of sealed radioactive sources from
inventory and integrity testing were selected to yield a committed effective
dose equivalent of 10 mrem (100 Sv) or less for a credible incident
involving a member of the general public. Even though the probability is
small, it was assumed that the sealed radioactive source was lost off-site
and located in the private residence of a member of the general public.  For
each radionuclide in Appendix B, the following two values were calculated:
(1) the activity of material that would result in a dose equivalent from
external radiation of 10 mrem in a year assuming an individual was
irradiated continuously at a distance of 1 meter from the source (Kerr, G.D.
and Eckerman, K.F., "Source Inventory Limits," Health Physics,Vol. 59, p.
931-934 (HP, 1990)); and (2) the activity of material that would result in a
committed effective dose equivalent of 10 mrem (100 micro-Sv) assuming that
1% of the material is inhaled by an individual during the incident.
Committed effective dose equivalent values from Table 2.1 in the
Environmental Protection Agency Federal Guidance Report No. 11, "Limiting
Values of Radionuclide Intake and Air Concentration and Dose Conversion
Factors for Inhalation, Submersion, and Ingestion" (EPA, 1988), were used in
determining the internal dose component.  The external and internal dose
values were compared and the more conservative value was chosen as the basis
for the exempt value.  If both of these values were greater than 300 Ci (11
MBq), then 300 micro-Ci was used as the exempt value.  Exempt values were
rounded to the nearest magnitude of 3 (i.e.,300, 30, 3, 0.3, 0.03, 0.003, or
0.0003 micro-Ci) to allow ready conversion to becquerels when SI units are
fully implemented at DOE facilities.  For example, if it took 2 micro-Ci of
a radionuclide to produce 10 mrem in a year from external radiation and 30
micro-Ci to yield a committed effective dose equivalent of 10 mrem from
inhalation, then the 2 micro-Ci value (rounded to 3 micro-Ci) would be the
exempt value.


        *********************************************************
        The opinions expressed are mine and do not necessarily 
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**********************************************
	Kurt R. Geber
	Lockheed Martin Energy Research Corp.
	Oak Ridge National Laboratory
	P.O. Box 2008
	Oak Ridge, TN  37831-6160

	Internet:	kg1@ornl.gov
	Phone:		423-574-0929
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