Re: MDA of radionuclides in soil (Regulatory Issues)???

[jgbarnes@ix.netcom.com (JAMES BARNES)]

Good morning;

I read Bill's note with some interest.  But I must admit that I am a bit confused 
by this.  In my former life in commercial nuclear, I was explicitly told by an 
NRC inspector that the Tech Spec LLDs were NOT to be interpreted as a "maximum 
acceptable" anything, as that was tantamount to a deminimis release limit, and 
the NRC did not recognize such deminimis limits (this all, of course, revolving 
around the dark planet of "detectable peak" as the basis for declaring something 
as radioactive).  [This is circa 1984; Region 1].

Later (1993; Region IV) I was given a listing of the NRC soil limits for facility 
release ("Policy and Guidance Directive FC83-23:  "Termination of Byproduct, 
Source and Special Nuclear Material Licenses").  This document specifies no 
acceptable concentrations, saying that they will be determined on a case by case 
basis.  Then in another attached chart (I think from an EPA document), levels of 
5 - 15 pCi/g are listed for the main byproduct players.  If these are the limits, 
then one would think these would also be the LLD (but I've even been told that 
THAT is not even true.  Several inspectors have said that we had to detect to 
levels below the limit).

I have always had the consideration that the regulators were using LLD to set 
release limits.  Thus, I have always cringed when the count room folks tell me 
that they got some fractional pCi/g for Cs-137 after a 5 billion second count, as 
that is a detectable peak, and that makes the material radioactive.  Has the 
regulatory community revisited this rule and broken the vicious circle?  If so, 
would someone please point me to the relevant guidance?

Thanks,


Jim Barnes, CHP
RSO
Rocketdyne Divison; Rockwell Aerospace
--------------------------------------------------------

You wrote: 
>
>
>--Boundary-1613719-0-0
>
>The licensing documentation (Technical Specifications, Offsite Dose 
>Calculation Manual, etc.)for nuclear power plants specify detection 
>capabilities for environmental sample analysis. These are defined as the 
>maximum acceptable LLD's.  Although none are specified for soil, the LLD's for 
>"sediment", in units of pCi/kr (dry) are 150 for Cs-134 and 180 for Cs-137.  
>These are 10X the LLD's for water, in units of pCi/liter.  We thus generally 
>take the required LLD's for sediment as 10X those for water.  They would be: 
>H-3    20000 
> 
>Mn-54, Co-58, Co-60, Zr-95, Nb-95, Ba-140, and La-140   150 
> 
>Fe-59 and Zn-65      300 
> 
>I-131    10  
> 
>Contact me directly if you need additional information. 
> 
>Bill Lipton 
>
>
>
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>Received: 23 Feb 1996 10:16:27                    Sent: 23 Feb 1996 09:15:03
>From:"root@romulus.ehs.uiuc.edu" <root@romulus.ehs.uiuc.edu>
>To: Multiple,recipients,of,list,radsafe@romulus.ehs.uiuc.edu
>Subject: MDA of radionuclides in soil
>Reply-to: radsafe@romulus.ehs.uiuc.edu
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>
>Does anybody know of a reference which has values of realistically
>achievable Minimum Detectable Activities for various radionuclides (as many
>as relevant) in soil?
>
>Thanks,
>
>Kim Kearfott.
>
>
>**********************************************************************
>                  Kim Kearfott, Sc.D., C.H.P.
>
>Professor                           Director of Faculty Development
>Program Advisor,                 & Faculty/Women in Engineering Office
>  Radiological Health Engineering   College of Engineering
>Dept. of Nuclear Engineering
>    & Radiological Sciences
>University of Michigan              University of Michigan
>Ann Arbor, MI 48109-2104            Ann Arbor, MI 48109-2116
>
>                 telephone: (313) 763-9117
>                       fax: (313) 763-4540
>                    e-mail: kearfott@umich.edu
>**********************************************************************
>     TIME, DISTANCE, AND SHIELDING: Good for what ails you!
>**********************************************************************
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>
>--Boundary-1613719-0-0--
>