[ RadSafe ] More questions about 10CFR 20

Sandra Matzkin matzkin at invap.com.ar
Tue Jun 3 11:31:54 CDT 2008


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:

(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.

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

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