Re: Accidents and Dose Limits

["Rey The_Fed_Man" <rad_con@hotmail.com>]

Will,

Your legal people are correct  --- if you receive a dose greater than 
the legal limit, you have exceeded the limit and can expect to be cited.

However, your car analogy deals with a whole different area of the 
regulations ... design, siting criteria, and safety classification of 
components.  Let me put it in perspective with respect to DOE 
regulation.

When a contractor proposes to build a facility (a "car") we require that 
he meet certain criteria called Risk Evaluation Guidelines.  The REGs is 
essentially a risk table with consequences (dose) on the y-axis and 
annual probability (of the accident) on the x-axis.  For lower 
probability accidents, then we (DOE) accept higher consequences .. and 
so forth.  Now, the contractor must design his facility such that 
postulated accidents will not produce consequences (dose) to the public 
etc. that will be greater than the REG values.

At DOE sites, these REG values for the public typically range around 25 
rem/event for a probability of 10E-6/yr (extremely unlikely) type of 
accident.  For workers, the acceptable accident dose limit ranges from 
100 to 25 Rem per event for accidents in the 10E-6/yr range.

These are not "dose limits" in the sense that you and I normally think, 
but they are accident dose limits.  The NRC doesn't have exactly the 
same scheme of REGs, the concept of designing plants to <25 rem accident 
dose limits is in 10 CFR 100.10 siting criteria.

For NRC's spent fuel storage facilities, the NRC's accident dose limit 
for the public is 5 Rem at 100 meters for design purposes;  it is in 10 
CFR 72.106(b).

A really good discussion of the DOE accident dose limits, how they were 
derived, etc. can be found in a two volume set of reports dated June 23, 
1994.  (EH-12-94-01 "Method for Assessment of Worker Safety under 
Radiological Accident Conditions at Department of Energy Facilities" 
Vols. I and II)  Just how there criteria are applied in selection of 
safty class equipment can be found in DOE Order 5480.22 and DOE Order 
5480.23 and the new DOE Standard DOE-STD-3009-94.  These later standards 
are on the internet.

Hope this helps.

Rey Bocanegra
Sr. Technical Advisor on Rad Protection
DOE, Hanford Site
reynaldo_rey_bocanegra@rl.gov


>From server@romulus.ehs.uiuc.edu Fri Nov 21 16:24:18 1997
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>Date: Fri, 21 Nov 1997 18:26:12 -0600 (CST)
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>From: William McCabe <WMCCABE@tnrcc.state.tx.us>
>To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
>Subject: Accidents and Dose Limits
>X-Listprocessor-Version: 6.0c -- ListProcessor by Anastasios Kotsikonas
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>
>I am having a discussion with our legel staff regarding accidents and
>dose limits.  Our legal people are telling me that the regulatory dose
>limits (100 mrem/yr as well as the 25 mrem whole body, 75 mrem thyroid,
>and 25 mrem other organ to any member of the public) and effluent
>concentration limits (i.e. 10CFR20, App B) and other such limits, as
>applicable, apply.  Their opinion is based on how they are reading our
>state equivalent of 10CFR (essentially the same as 10 CFR).   (It seems 
to
>me that this is like saying it is agtainst the law to receive anything 
more
>than minor cuts and bruises ANY traffic accident.)
>
>It has always been my understanding that you cannot apply a regulatory
>dose limit or effluent concentration limit to a radiological  accident.  
All you
>can do is plan and prepare for any reasonable or credible accident
>situation and do everything you can to prevent the accident from
>occurring and take action to mitigate the consequences of the accident 
if
>it should occur.  (To continue my earlier analogy... install automobile
>safety devices, design vehicle to absorb and distribute impact energy
>away from passenger, require seat belt use, etc.  This will not prevent
>exceeding minor cut and bruide injuries, but will (should) help 
minimize
>more serious injuries and death).
>
>I'd appreciate any comments and especially references and other state
>and federal regulatory positions or guidance on this subject from the
>RADSAFE community to help clear up either my or my legal people's (or
>both our) misconceptions.
>
>Thanks in advance.
>
>Will McCabe
>wmccabe@tnrcc.state.tx.us
>


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