[ RadSafe ] More questions about 10CFR 20
matzkin at invap.com.ar
Tue Jun 3 14:24:49 CDT 2008
Thanks for pointing out this document
(NUREG-1736), I think the discussion sections in
it will be particularly useful.
Maybe I should remark that the project to which
these questions apply is not a nuclear reactor,
but rather a facility where irradiated material
is to be processed. It is currently under design,
so measurements in these stage are out of the question.
At 15:41 06/03/2008, WILLIAM LIPTON wrote:
>NOTE: The best source of answers regarding
>interpreting 10 CFR 20, is found
>in: "Consolidated Guidance: 10 CFR Part 20 -
>Standards for Protection Against Radiation
>(NUREG-1736)". This is available from the NRC
>web site: <http://www.nrc.gov/>www.nrc.gov
>. >From the home page, click on the
>"Electronic Reading Room" tab, and then on
>"Collections of Documents By Type." From there, go to the NUREG publications.
>As I mentioned in my response to your previous
>post, the effective limits for nuclear power
>plants are significantly lower than those of 10
>CFR 20.1302. There are tiers of limits. Some
>apply to the maximum dose at the site
>boundary. Others apply to the maximum exposure to a real person.
>Nuclear power plant licensing requires a
>detailed, site specific assessment of the
>offsite doses due to reactor operation. This
>assessment is summarized in the plant's "Final
>Safety Analysis Report," and results in an
>"Offsite Dose Calculation Manual" (ODCM), which
>has site specific equations for determining
>offsite doses, based on effluent monitor
>readings, and for determining the alarm
>setpoints for these monitors. In general, PWRs
>use real time meteorological data, since they
>can control when gaseous effluents are
>released. The gaseous effluent volumes for
>BWRs, however, do not permit their storage,
>requiring continuous releases. Thus, BWRs
>generally apply a conservative annual average of
>meteorological parameter values. A nuclear
>power plant is required to perform an annual
>"land use census," to determine the critical
>pathways for populations exposure to gaseous and
>liquid effluents, and to revise the ODCM if
>there is a significant change to a critical pathway.
>I recommend looking at the following NRC
>Regulatory Guides: 1.21, 1.23, 1.109, 1.111.,
>1.112, 1.113. These are also available from the
>NRC web site: www. nrc.gov. From the home
>page, click on the "Electronic Reading Room"
>tab, and then on "Collections of Documents By
>Type." From there, go to the Regulatory Guides.
>It's not about dose, it's about trust.
>----- Original Message ----
>From: Sandra Matzkin <matzkin at invap.com.ar>
>To: radsafe at radlab.nl
>Sent: Tuesday, June 3, 2008 12:31:54 PM
>Subject: [ RadSafe ] More questions about 10CFR 20
>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.
>Nuclear Engineering Department
>You are currently subscribed to the RadSafe mailing list
>Before posting a message to RadSafe be sure to
>have read and understood the RadSafe rules.
>These can be found at:
>For information on how to subscribe or
>unsubscribe and other settings visit:
More information about the RadSafe