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Re: Emergency Doses Allowed
David,
You bring up an interesting question whether 10 CFR 835.1302 exposure
guidelines are TEDE or external whole body doses. My view has always
been that they are the latter --- i.e. WB external dose limits.
Although I could not find a Gospel basis to back my opinion, there are
two points to note in the regulation: 1) the table indicates in
parenthesis that the doses are "whole body" --- this is the traditional
"old" Part 20 language; and 2) footnote No. 1 to the table expands and
explains what "Doe limit" means. Had the regulation intended to include
CEDE in the emergency "dose limits," the footnote would most likely have
indicated this.
Rey Bocanegra
Sr Technical Advisor on Rad Protection
Dept of Energy
Once again ... these are my opinions only -- and these could easily
change if coerced, threatened, or offered a raise!
>From server@romulus.ehs.uiuc.edu Thu Jun 4 11:33:20 1998
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>Subject: Re: Emergency Doses Allowed
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>Rey:
>
> As long as Steve Hand has reopened this issue of dose guidelines for
>"emergency situations," you may recall that about a year ago, Joyce
Davis
>of the DOE Defense Board posted a message to RADSAFE wherein she
>essentially asked if the emergency dose guidelines included internal as
>well as external dose. I don't have a copy of her original post in
front
>of me, but as I recall, her rationale was something like this:
>
> (1) Prior to 1991, when the NRC adopted ICRP 26/30 methodology, the
>occupational dose limits were dose limits for EXTERNAL radiation only.
Any
>internal dose was considered separately; pre-1991 10 CFR 20 did not
track
>CEDE and TEDE. Under the pre-1991 10 CFR 20 dose accountability/limit
>regime, any doses sustained in any sort of emergency clearly were
numerical
>limits that pertained to EXTERNAL whole-body (WB) radiation only.
Thus,
>whatever the doses were that were recommended as "guidelines" or
specified
>as "limits" were whole-body doses incurred as a result of external
ionizing
>radiation exposure.
>
> (2) Post 1991 10 CFR 20, however, included any internal CEDE with any
>external effective dose equivalent (DE) under the total allowed dose
>limits, i.e., CEDE + effective DE external = TEDE. But it does not
appear
>that the NRC clearly indicated whether the doses permitted for planned
>special exposures were TEDE doses or just WB external doses as before
>(pre-1991 10 CFR 20).
>
> (3) As I recall, Joyce pointed out that IF the dose limit recommended
for
>an "accident" or some sort of "emergency" includes the internal dose,
i.e.,
>CEDE, then for long-lived radionuclides, e.g., Pu-239, it just takes
little
>more than atom amounts of such nuclides to impart a CEDE of 25 rem, 50
rem,
>etc., and that the accidental intake of such a few number of atoms
>basically can happen at some nuclear facilities that routinely handle
>long-lived alpha emitters at a frequency that many would consider to be
far
>higher than just a once in a blue moon "accident/emergency."
Therefore,
>paraphrasing her statements, if the 10 CFR 20 emergency dose guidelines
and
>similar 10 CFR 835.1302 guidelines are TEDE doses rather than just
external
>effective DE doses, then we as a Radiation Safety community need to
come up
>with a much higher, more realistic CEDE dose guideline for "emergency"
>situations, particularly in the case of long-lived alpha emitters.
>
> So perhaps having crudely paraphrased Joyce's original message of
about a
>year ago, what is your interpretation of the emergency exposure dose
limits
>specified in 10 CFR 835-1302? Are the dose limits ranging from 5 to
>greater than 25 rem for "emergency exposure situations" TEDE limits or
mere
>external WB limits? It seems to me that these dose limits are external
>limits/guidelines, but I can't seem to find anything in the text of 10
CFR
>835 that clearly says so.
>
> Perhaps many RADSAFERS replied to Joyce's original post of a year ago
to
>her private e-mail address, but I don't recall any RADSAFER ever
offering a
>response back to her over the RADSAFE net such that we all could read
it.
>
>Best regards David
>
>
>
>
>At 04:15 PM 6/3/1998 -0500, you wrote:
>>Steve, et. al.
>>
>>The U.S. Department of Energy currently has dose guidelines for
>>accidents and emergencies in the regulations (10 CFR 835.1302) The
dose
>>limits run from 5 rem for all emergencies to >25 rem for lifesaving of
>>large populations. 25 rem is the dose limit for "lifesaving or
>>protection of large populations." There are other caveates too
numerous
>>to mention here.
>>
>>58 FR 65483 makes it very clear that these values are only guidelines
>>and they have been removed from the proposed revision to 10 CFR 835
---
>>I'm not exactly sure why.
>>
>>
>>Rey Bocanegra
>>Sr Tech Advisor on Rad protection
>>DOE
>>
>>Don't usually add disclaimers to what I say, but .....
>>The facts I mentioned above are not mine ... just the facts.
>>
>>>From server@romulus.ehs.uiuc.edu Wed Jun 3 12:34:31 1998
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>>>Date: Wed, 3 Jun 1998 14:35:25 -0500 (CDT)
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>>>From: steve hand <hand@wam.umd.edu>
>>>To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
>>>Subject: Emergency Doses Allowed
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>>>Dear Radsafers:
>>>
>>> Please advise on the limits allowed in an emergency with
references
>>>to literature if possible. I have NCRP REPORT No. 91 and 116. In
116
>>>chapter 14 page 44 says
>>>"for life saving or equivalent purposes the equivalent dose may
>>approach
>>>or exceed 0.5 Sv to a large portion of the body in a short time.."
The
>>>highest limit I can find in 10 CFR 20 for allowed doses is .25 Sv or
5
>>>times the annual for a planned special exposure.
>>>
>>>1. In the case of an emergency that is life threatening to an
>>>individual, can someone get up to .5 Sv to try and save them, or up
to
>>>.25 Sv to try and save them ?
>>>
>>>2. Rather than use one person in question 1 above, should several
>>>people be used for a total of .5 or .25 Sv for life saving? I seem
to
>>>remember reading something about not spreading the dose out anymore
to
>>>several individuals.
>>>
>>> Thanks
>>>
>>>
>>>steve hand
>>>university of maryland
>>>radiation safety
>>>hand@wam.umd.edu
>>>
>>>
>>>
>>
>>
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>>
>
>DAVID W. LEE
>Los Alamos National Laboratory
>PO Box 1663, MS K483
>Los Alamos, NM 87545
>PH: (505) 667-8085
>FAX: (505) 667-9726
>lee_david_w@lanl.gov
>
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