[ RadSafe ] More questions about 10CFR 20

[Jerry Lahti]

Because the doses due to effluents beyond the restricted area boundary are
generally fractions of the natural background, compliance is demonstated by
dose calculations, not measurements.  

The methodology for these dose calculations is included in a licensee document
called the Offsite Dose Calculation Manual (ODCM) that contains relevant
parameters (usually USNRC Reg Guide 1.109) and site-specific meteorology and
aquatic dilution information.  The methodology in the ODCM and the measured
radiological releases are combined to obtain doses to demonstrate regulatory
compliance included in the licensees annual repoorts.  

There is also an environmental monitoring program in place to demonstrate that
doses do not exceed applicable regulatory criteria. 

--
Jerry Lahti
Naperville IL


---------- Original Message -----------
From: Sandra Matzkin <matzkin at invap.com.ar>
To: radsafe at radlab.nl
Sent: Tue, 03 Jun 2008 13:31:54 -0300
Subject: [ RadSafe ] More questions about 10CFR 20

> Radsafers,
> 
> I'm now fighting with Section 20.1302 (Compliance 
> with dose limits for individual members of the 
> public) of 10CFR 20. I have some questions 
> concerning the possible ways of demonstrating 
> compliance with the dose limits for individual 
> members of the public. Quoting again:
> 
> SNIP..."
> (b) A licensee shall show compliance with the 
> annual dose limit in § 20.1301 by--
> 
> (1) Demonstrating by measurement or calculation 
> that the total effective dose equivalent to the 
> individual likely to receive the highest dose 
> from the licensed operation does not exceed the annual dose limit; or
> 
> (2) Demonstrating that--
> 
> (i) The annual average concentrations of 
> radioactive material released in gaseous and 
> liquid effluents at the boundary of the 
> unrestricted area do not exceed the values 
> specified in table 2 of appendix B to part 20; and
> 
> (ii) If an individual were continuously present 
> in an unrestricted area, the dose from external 
> sources would not exceed 0.002 rem (0.02 mSv) in 
> an hour and 0.05 rem (0.5 mSv) in a year.
> "...SNIP
> 
> Option (2) seems pretty strightforward. However, 
> I wonder about option (1) since it looks more 
> like the approach set by the Argentinean 
> regulatory body. When applying for a license, the 
> applicant has to assess the allowable activity 
> for each individual radionuclide (Ki) to be 
> released (as if radionuclide "i" was the only one 
> to be released) and demonstrate that the 
> summation -over all radionuclides released- of 
> the ratios Si/Ki, where Si is each of the 
> individual activities to be released, is lower 
> than or equal to 1.  That is, SUM(Si/Ki) < 1.
> 
> This formula ensures that the total effective 
> dose equivalent to the critical group will be 
> within prescribed limits. The Ki's are calculated 
> through a long process which requires many data: 
> meteorological, hydrological, agricultural, 
> population distribution, even food consumption 
> habits of the people living in the region, as 
> well as dosimetric factors associated to each radionuclide.
> 
> And now the questions:
> a) which is the customary approach to demonstrate 
> compliance with dose limits to the public when 
> applying for the licensing of a nuclear (not power) facility in the USA?
> b) when (or if) option (1) is used, is the 
> procedure similar to what I've described above? 
> if so, which is the official -if there is one- 
> source for the dosimetric factors? I've searched 
> through the NRC site but didn't find anything related.
> 
> Sorry for the long post. Once again, I'll appreciate your inputs.
> 
> Sandra Matzkin
> Nuclear Engineering Department
> INVAP SE
> Bariloche
> ARGENTINA
> 
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------- End of Original Message -------