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Re: external dose evaluation





There is a caveat to all this and that is that the particular licensee has

to make this methodology a part of the license obviously before any over

exposure and not back peddle after the fact trying to obscure an inability

to follow their procedures or the regulations. The approval to use these

weighting factors is not automatic either.



The particular 10CFR20 reference to this is found in the definitions under

weighting factor. Footnote 2 of the given table reads:



For the purpose of weighting the external whole body dose (for adding it to

the internal dose), a single weighting factor, w_T = 1.0, has been

specified. The use of other weighting factors for external exposure will be

approved on a case-by-case basis until such time as specific guidance is

issued.



This little note may or may have not made into any particular Agreement

States regulations. Just because you want it doesn't mean you are going to

get it. Convincing the regulatory bodies that this method applies in your

situation will probably involve some local studies on your part using

multi-badging to demonstrate that the assumptions used in the methodology

applies in your situation. The bottom line is that the licensee has to know

quite a bit about the radiation fields their folks will be working in to

convince regulators that the methodology applies.



Another thing to keep in mind is that using these weighting factors does

not absolve you of ALARA responsibilities and they should not be used to

"push the limits" so to speak.



DJWhitfill



Opinions expressed are mine and do not reflect official policies or

positions of the Kansas Department of Health and Environment.





                                                                                                                             

                    "Sandy Perle"                                                                                            

                    <sandyfl@EARTHLINK.NET>        To:     radsafe@list.vanderbilt.edu                                       

                    Sent by:                       cc:                                                                       

                    owner-radsafe@list.vand        Subject:     Re: external dose evaluation                                 

                    erbilt.edu                                                                                               

                                                                                                                             

                                                                                                                             

                    10/02/01 01:23 PM                                                                                        

                    Please respond to                                                                                        

                    "Sandy Perle"                                                                                            

                                                                                                                             

                                                                                                                             









Bill,



I currently am providing the ANSI N13.41-1997 effective dose weighting

calculation in one SE

state (not under NRC jurisdiction). This method does result in a higher

dose than most of the other

dose weighting methodologies.



The NRC has been considering the use of dose weighting, even sponsored the

EPRI Meeting

back in 1997. Unfortunately they have not moved on it. Hopefully now they

will allow use of the

various methodologies, as you outlined. I can currently provide the Webster

(99%), Niklasson (1

client) and the N13.41 (1 client).



Dose evaluations will obviously change for the better.

------------------------------------------------------------------------

Sandy Perle                   Tel:(714) 545-0100 / (800) 548-5100

Director, Technical           Extension 2306

ICN Worldwide Dosimetry Service    Fax:(714) 668-3149

ICN Pharmaceuticals, Inc.          E-Mail: sandyfl@earthlink.neI

ICN Plaza, 3300 Hyland Avenue      E-Mail: sperle@icnpharm.com

Costa Mesa, CA 92626



Personal Website: http://sandyfl.nukeworker.net

ICN Worldwide Dosimetry Website: http://www.dosimetry.com





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